“People don’t understand the impact of ‘beyond compliance’ and what it requires,” said Mark English, as we were discussing Title 24 energy compliance for various types of custom home designs and remodels. “They don’t understand the difficulty of getting even very small additions to comply – and if they have to meet local green building ordinances that require exceeding Title 24 by 15% or more, it’s even more challenging.”

The problem with additions is that you have less to work with if the project doesn’t comply. Small additions are the hardest, and alterations are even worse, because you’re not adding any conditioned area. If it doesn’t qualify for prescriptive (simple but rigid), you have no choice but to do a whole house energy model. And with the energy model method, you have to justify the values used for the rest of the house that’s not being touched, and which may be built to a long-obsolete energy standard. Those existing R-0 walls can cost you.

Local Green Building Requirements Can Differ

Local green building ordinances can vary in very unpredictable ways. Some areas are adopting BuildItGreen’s GreenPoint Rated system, which at a minimum requires 15% over compliance for new construction. That alone means an energy model, since you can’t “exceed” compliance using the prescriptive form. With the simpler prescriptive form it’s very black and white: either you meet every requirement, or you don’t comply – there’s no extra credit in one area to make up for shortfalls in another.

And it’s not just the GreenPoint checklist that the jurisdictions want, either. If a local Building department is using the GreenPoint Rated system, they often want to see the full follow-through, with a third-party rater who checks up on the project all the way through construction. Others are adopting CALGreen optional tiers, which have pretty much the same measures as BuildItGreen, but it’s structured differently – and that can also have an impact. A locality can even adopt a green building ordinance all on its own that doesn’t reference these systems, although that’s less likely than choosing one standard and then piggybacking further requirements on top of it.

For example, Portola Valley has added a sliding scale GreenPoint score where the larger the house, the more GreenPoints it needs. One of our recent Title 24 projects, a new 6,000 square foot house with 40% glazing to floor area, and metal framed windows (less efficient) required 172 GreenPoints, and in order to make that, we needed to get that house to exceed Title 24 by 35%!

At least with that project, we had the whole house design to work with. We got that project early in the design phase, so we could work with the architect to specify better windows, test out the impact of various system efficiencies, and discuss the additional credits of HERS testing with the assurance that it would likely pass all those tests. With additions, you have to perform the same miracles without altering the majority of the building. And you never know what a local green building ordinance may require.

Even Interior Remodels Now Require Title 24 – in Burlingame

Here’s an example that just came up, and is the subject of this case study. One of our recent Title 24 projects, a remodel of a private home in Burlingame, CA, was mainly an interior remodel. Who knew that Burlingame has an expenditure threshold where any construction project costing over $50K now triggers a Title 24 compliance requirement that has to beat the standard by 15%? And a GreenPoint Checklist with a minimum of 50 points? It’s not like they’re even changing the building envelope.

Well, Mark ran this project and it was -174% behind. “It simply couldn’t be done,” he told me. “It was a nice Mid-Century Modern home with lots of glass everywhere, and vintage insulation. Even if we replaced every window and the heating system, we wouldn’t even make the baseline, let alone 15% over.”

The home's existing condition, before the interior remodel which had no impact on the exterior envelope whatsoever, failed Title 24 by an impossible margin. Note that California's energy code assumes a minimum 13 SEER cooling system, whether any cooling is installed or not.

Mark spoke to a Burlingame city Green Building official, who bluntly told him, “You can apply for a hardship exemption, but you’re not likely to get it.” The owner, a medical professional whom we’ll call Dr X, was already committed to making this project happen. This would have crushed the project completely – and for no justifiable reason.

Then, Mark had a brainstorm. He talked the owner into replacing the heating system with top-of-the-line efficient equipment, and then he created two separate reports: a “before” and an “after”. The “after” report was only (only!) -120% under, a 50% improvement! The home didn’t have any cooling system installed, so no help there. Title 24 assumes you have one even if you don’t, and penalizes accordingly.

The owner agreed to upgrade his heating system and got a 50% improvement.

A Happy Outcome

The owner then submitted the two reports to the City, along with a hardship application form – and to everyone’s astonishment, he got his permit. He wrote us a lovely handwritten note:

“Dear Mark,

Many thanks for all your work and suggestions. I turned in your Title 24 analysis and the hardship for with your wording plus additional palaver and got the permit Monday. It would have been a bleak Thanksgiving if I was still in a suspended state. I really appreciate everything you did.

Best,

Dr. X.”

Lessons Learned

What are the lessons to be learned from this exercise, aside from the fact that new regulations can have unanticipated consequences? Here is what we concluded:

1. Don’t assume that additions are easier than whole-house remodels. You have a lot less to work with and fewer opportunities to improve performance.
2. It’s very hard to get an addition to comply on its own.

Be told.

Impact of Poorly Designed Regulations Can Be Catastrophic

Mark English, ever the advocate for both architects and homeowners, put it this way. “You can’t inhibit people from upgrading their homes – it only kills the economy and prevents construction from happening at all. You can’t hold people hostage and force them to rebuild their entire house for some ridiculous bureaucratic rule that no one’s thought through. At the very least, Burlingame should raise that construction threshold to something like $200K, because any interior remodel, even a kitchen and master suite, can easily cost $125K and more – without any changes to the envelope.”

This goes back to one of our earlier articles on QII credits for spray foam – another “gotcha” that almost cost one of our Title 24 projects its compliance in the field – too late in the game to make it up easily through design or construction changes. The way regulatory processes work, the people writing these codes can’t anticipate their impact in the field, unless we bring it to their attention. I sure hope they see this article!

Remember last week, when we were talking about glass houses? Well, here’s another Title 24 case study on a 4,500 SF house, also from Swatt|Miers Architects. This house had almost 60% glazing to floor area, much of it custom built on site: 564 square feet of single paned butt glazed corner windows, 540 square feet of frameless glazing, a steel framed window, a 30 foot tall translucent window in a stair tower, 300 square feet of skylights, and a custom built wood screen interspersed with glass panels. That’s almost 2,700 square feet of glass.

And, to make the challenge that much more… piquant… it was in California climate zone 2 (Sonoma – HOT)… AND, they needed to beat California’s Title 24 energy standard by 15% because of local ordinances. It was the combination of all that single glazed area with the climate zone that concerned us the most. But, we had a reputation to maintain, and our motto to designers was, “We’ll never tell you that you have to shrink your windows.”

(Above image courtesy Swatt|Miers Architects.)

Well, we did end up telling them that they would have to find a way to make the butt glazing work with double panes (which we described in our article on window performance). So I suppose now we have broken our cardinal rule of never impacting the visible design.

Complex Shapes

Although the design was entirely based on rectangular planes, the volumes didn’t always line up one stacked directly over the other. This meant that there were some extra floor and roof areas to account for, and there were some subtle variations in building height, too. Most of the time, this can be generalized, but in this case we wanted to be as exact with every surface area as we could, so that we could claim the maximum thermal mass credit. I knew the planners might be reviewing the report against the drawings with a fine-toothed comb, and we needed to be prepared to respond to any comments with a solid grasp of facts.

Wood framed overhanging floor areas were modeled separately from the slab flooring on the main level.

Start at the Beginning, Grasshopper

As we mentioned in the previous case study, we try to start at a basic level with whatever systems information we have from the designer, and then work up from there. The main heating system was radiant, with A/C. On the plus side, the design called for slab flooring, with gypcrete on the upper level – this thermal mass gave us a ray of hope. Even so, the first trial was dismal. 73% below the standard. Heating was missing by 75% and cooling was missing by a whopping -136%. Only pride kept me from throwing in the towel – pride and curiosity.

“Patience, Grasshopper,” I said to myself. “Just do what you usually do, and don’t say anything until you have some good news to report.” So, here’s what we did, and what worked the best.

Cool Roof/Radiant Barrier. Although this seems like a minor place to start, we’d have to try a cool roof at some point, and it might actually help in Sonoma. The cool roof did make a difference (down to -67%), although the cooling improvements were offset by a small detriment on the heating side. What we really needed was a selectively cool roof, that changes color based on outside temperature – maybe someday soon there will be such a thing. The radiant barrier helped less, and they would have had to change the roof construction to include it. The gains from the barrier didn’t justify including it – unless we absolutely had to.

Wall insulation. Next, we upped the wall insulation from the requisite R13 to R21. That pushed us from -67% to -55%. Pretty good, but still way behind. The designer had thoughtfully provided us with the wall assemblies, so we knew that the cavities were 2 x 6 – large enough to fit R21.

The designer provided us with complete details, which helped us to ascertain how much insulation we could specify in the energy model. Image courtesy Swatt|Miers Architects.

Ducts. There would be both heating and cooling ducts in this project. Although the main heating system was radiant, there would be a forced air backup. We couldn’t model both systems, but we had to keep the heating ducts in the energy model, which cost us. We did verify with the designer that the ducts would be located within conditioned space, which gave a credit. And, we added the HERS test for duct leakage, which brought us from -55% to -40%. (Actually, we tried eliminating the heating ducts and it didn’t help as much as it had on other projects.)

Blower Door Test. With heating and cooling ducts within conditioned space and the duct test taking us to -40%, we added another HERS test – the blower door test, which measures the airtightness of the entire home. Doing these HERS tests on a sizeable house such as this was bound to be challenging, so we stressed to the designer that they, and their builder, should read our article on HERS tests so that they knew what was involved. The builder in particular would need to know that the project was required to pass these tests. The blower door took us from -40% to -37%, not that much. Well, we’d keep it in for now, since it was looking like we’d need every last inch of compliance.

A/C Verifications. Next, we tried adding the HERS tests that apply to air conditioning systems: test for refrigerant charge, airflow, fan watt draw. These took us from -37% to -32%. I had hoped for more. We tried upping the A/C SEER from the standard 13 up to 18 SEER, which, together with the HERS tests, brought us to -29.5%. One thing to note is that often, the HERS tests have more of an impact on compliance than simply upping the SEER. But, all of this was simply postponing the day of reckoning, which was to attack the windows.

Window Performance

As with the other Swatt|Miers case study, we divided up all the window areas by type: Butt glazed corners, frameless wall insets, the stair tower, the custom steel window, various sliding pocket doors, operable casements, the 40 foot long wood screen window on the upper gallery, and the skylights. The design called for various overhangs, including a large canopy extending over the main house and a separate guest house. Most of the window framing was metal, which is not as good an insulator as wood.

Initially, I used the performance specs from Efficient Windows as a starting point for estimating all the custom areas, assuming that all windows with the exception of the corner butt glazing would be double paned, low e glass. There was a lot of back and forth with the designer to establish the composition and construction of the various custom windows. We couldn’t go any better than the standard on most of these (we were lucky to get the standard). The casements and the sliding pocket doors were Fleetwood window products, with numbers that we could look up.

I asked around and searched for information on whether any sort of single glazed window could ever be “high performing”. Alas, there was no magic glass. The experts all informed me that the main factor in window performance is 1) multiple panes with insulating layers of air or gas fill 2) airtightness of the frame itself and 3) insulating properties of the framing material. There was no such thing as a thermally  broken, metal framed window with single glazing, because why? There wouldn’t be any demand for it.

But we were still at -29%. Something had to give. So, I broke our rule and made all those butt glazed corner windows double glazed. That took us to -11%. And then, I modeled the Fleetwood windows using the best numbers they had available for each type. That took us to -6%. At the same time, I put out the word to see if anyone had successfully built a corner glazed window with double paned glass, because I knew that the designer really wanted to keep that transparent appearance, and putting a spacer bar on the corners would be a major disappointment, to say the least.

And it still wasn’t enough. Even adding the dreaded QII test (a HERS test where every bit of insulation is inspected as it’s installed during construction) wasn’t enough, although the QII did bring us from -11% to -0.8%. So close – and yet not close enough, considering that we had another 15% to go.

Interior Mass Surfaces

At this point I dragged Mark English over and made him review the entire drawing set plus all the details. As an experienced architect who’s been designing and building homes for 25 years, I figured he’d see a few things that I had missed, and he would make sure we didn’t take too many liberties with the wall and roof cavities.

Based on consultations with Mark and numerous exchanges with the designer to verify the exact location of every wall and floor finish, we added the thermal mass of a dramatic 2-story stone veneer wall, over 1475 SF of thermal mass. Additionally we included all the tile flooring in the bathrooms, countertops, and the gypcrete from the second floor’s suspended slab floor. Even though this floor was largely covered by wood or carpet, it still yielded some credit. That took us from -0.8% to +12%.

Upon our request, the designer provided us with the location of vertical thermal mass surfaces - stone veneer walls - which we could then include in the energy model. Image courtesy Swatt|Miers Architects.

And it still wasn’t quite enough. I felt like a magician reaching into a hat for another rabbit and coming up with a hamster instead.

What the Designer Said

I figured it was time to fill in the designer with our progress to date, and test the waters about making the butt glazed windows double paned. It might be a good time to insist on an uber-efficient water heater. We’d actually started with a reasonably efficient one, a .80 energy factor, but without further information, I was hesitant to commit to anything extreme. Eventually we would have to include the actual models they were using, and there would likely be more than one with a house that size anyway. I don’t think they had worked out the mechanical systems to that detail, so now was a great time to test and suggest a few things.

But before we reached into our top hat for that last rabbit (the water heater itself), we tried a few more things just to see what would happen.

Solar water heating credit. The design hadn’t specified solar equipment of any kind. Well so what? Maybe it would let them keep that single glazing, although I doubted that.  Even though there’s no credit for the use of renewable energy for electricity or heat, there is Title 24 credit for solar hot water. It’s based on the percentage of hot water that the home is expected to get from solar, and sure enough, set this percentage high enough and the compliance score improved.  So, by pushing this number to an unrealistically high 50% we were able to inch our compliance from +12% over to 17% over, although I doubted that this would actually work.

And why not? Well, the problem with it is that you still need some kind of indirect storage tank to ensure hot water in the evening, unless you only plan to shower at high noon. In addition, this home would have extra water heating demand because of the radiant heating. But hey… we reached our goal, in theory at least.

Higher Solar Heat Gain on Some Windows

On the last case study, I had, purely out of curiosity, tested a series of window performance combinations just to see what would happen. Although a low U value window was always the best choice, because it provided thermal insulation for both hot and cold temperatures, what could we do if the best U value we could find was average – if that? Since we had so many custom windows that would be built in the field, we couldn’t make aggressive assumptions about them.

So, I inched up just the solar heat gain on the Fleetwood windows, while keeping the U value the same. This would allow at least some glazing areas to keep up their insulating value, while allowing a little more solar heat. Although originally the design had lagged more on cooling, it was now the heating side that had all the shortfall. We were actually ahead on cooling. This latest change brought us from 17% over to 18% over, so it didn’t make a huge difference. Heating was better, cooling lost a bit.

Skylights

The skylights were another big unknown. There were a lot of them, and the designer indicated they didn’t want wood framed because they were concerned about leaks and such. Then they selected a manufacturer who actually had pretty good numbers, which brought us from +18% to +21% over.

Highest Efficiency Boiler

It was time to pull out our very last rabbit, which was to boost the water heater performance as far as it would go. By specifying a boiler with a 95% efficiency, and keeping a solar hot water credit at 25% (still probably too aggressive), we got the house to exceed Title 24 by 32%. At this point, we dialed back the Fleetwood windows to the actual numbers (Westwood and Norwood product lines, dual glazed low E, thermally broken, but no argon – air fill), and removed the solar hot water credit altogether. We kept the HERS testing for credits: the three A/C tests and the duct test.

The final score? It came out as exceeding Title 24 by 25%. This would give them a little margin if by some chance it didn’t pass every HERS test. Some of those tests were worth GreenPoints, too. So, chances are this house will earn a respectable GreenPoint Rated score as well once construction is complete.

A few final notes follow, on what the designer did to help us, and a note on modeling multiple zones.

Detailed Wall and Floor Assemblies

This was one of the few projects where the designer provided us with detailed wall and floor assemblies, 3 drawing sheets of it. This was great, because we could see exactly where the gypcrete was, which portions of the floor were covered (and with what) and which walls had interior stone veneers.

Although we don't always have to model every layer in the floor, in some cases it helps to know exactly what's in there. Image courtesy Swatt|Miers Architects.

Modeling Multiple Heating and Cooling Zones

This was something that we would have resorted to only at gunpoint, because it’s very time-consuming. Essentially, you model each zone as a separate volume – including floors, walls, and ceilings – as if it were its own little house. Title 24 gives credit for this, but I’ve only ever done it once on a private home, and we had no way of knowing how much it would help unless we tried it.

Actually the real question is whether an all-glass pavilion can still comply with the new version of California’s Title 24 energy code. Although Title 24 has been around since the 1970s, it is only now that designers are feeling the pinch. Given the increasing strictness of the energy code, what can an architect do if he (or she) wants to create designs with dramatic glass curtain walls?

The “glass house” shown on the cover image is, of course, Philip Johnson’s famous Modernist masterpiece, also called the Glass House. Even that house could, with the right high-performing window system, comply with Title 24 requirements – I tested it out. But, let’s talk about some more current designs for our case study.

When we got our first Title 24 project from Swatt|Miers Architects, I didn’t really know if we’d be able to finesse it. We had never had a project quite like it before. But then I remember seeing an award-winning Net Zero home in Truro, Massachusetts (by Zero Energy Design) which had acres of glass everywhere. If they could make it work in a cold place like Massachusetts, surely we could do the same in California!

This Net Zero home in Truro, Massachusetts, was designed by Zero Energy Design. And yet, this house still manages to be efficient even with all this glass. Photos: Eric Roth.

Our first Title 24 project from Swatt|Miers Architects was a 6,000 SF all-glass pavilion with a generous roof,  a custom window wall on one side, and heated slab floors. On the plus side, the roof included large shading overhangs, and we had ample time and flexibility to select high-efficiency heating and water heating systems. There were no large skylights or ductwork to worry about, either. The house was located in a moderate climate zone, so they weren’t even going to install any cooling systems at all.

Another big plus was they didn’t have any “beyond compliance” goals such as GreenPoints. So, we didn’t have to beat the standard by 15% or more. As you’ll see in a minute, that would have been possible, but very expensive.

On the challenge side, there was almost 5,000 square feet of glazing – 75% of the conditioned floor area. In addition, the design called for metal framed windows, which are inherently less efficient than windows framed in wood or vinyl. Even thermally broken metal windows can’t always match the performance of wood.

This house had 75% glazing to floor area and yet, it still managed to comply with California's Title 24 energy requirements. Design Courtesy Swatt|Miers Architects.

Strategy: Start Low, Increment Up

We usually start by running each project with baseline assumptions, usually the same ones used for the prescriptive Title 24 method. The Title 24 prescriptive method sets forth minimum requirements for things like heating and cooling performance, insulation levels, maximum allowable glazing areas, and window performance – but it’s all or nothing. Either you meet every requirement, or you have to use the performance modeling method to satisfy Title 24. The software model has some built-in generic inputs for things like water heaters that also assumes a very basic level of compliance.

Using the software modeling method of Title 24 energy compliance, a house can fall below the standard in one area as long as it makes up for that shortfall in another area.

In this case, the first trial missed by -76%, with shortfalls on heating and water heating. Surprisingly, cooling was not a problem – at least, not in the model. Still -76% seems like a big, scary number – one which we attacked incrementally.

Preliminary Trials with Insulation and Water Heating

Increasing insulation levels from R13 to R21 brought it to -67%. There wasn’t that much wall to work with, the walls being mostly glass, which is measured by window performance rather than insulation. The roof already had plenty of insulation, and adding more past a certain point had a negligible impact.

Just as a test, adding an overhang over the South window wall (which didn’t have one) actually made it worse! That’s one thing about trade-offs. Sometimes a measure that helps with cooling will create more load on the heating side, and heating was what we needed to fix. But this design didn’t specify an overhang there, and even when there are overhangs, modeling them is optional.

Next, we tried upping the water heater performance. Originally we’d specified a generic setting, because the mech hadn’t been worked out yet. For a house this size, over 6,000 SF, you probably wouldn’t have a single heater anyway, and you definitely wouldn’t be running all the hot water AND the radiant through one heater. So we had started with a 75 gallon storage tank with a .75 energy factor – legacy numbers.

A tankless heater with a storage tank, with 2 separate systems, and a higher energy factor, got us down to only -49% below Title 24 requirements.

Main Trials: Windows

But all this was simply prep, because the windows were going to be the biggest challenge. The window performance factors that are important for Title 24 are the U value, which measures thermal performance (keeps winter heat in), and the Solar Heat Gain Coefficient (keeps summer sun’s heat out). We had all been thinking that with all that glass, cooling would be the concern, and we’d have to get the lowest SHGC we could find. Not so. It was the U factor on all those windows that would make or break our compliance.

In fact, having a higher SHGC might help because we could afford to lose some cooling margin if the solar heat gain would actually help on the heating side. Passive solar designs in far North latitudes try to leverage the sun’s heat, especially in the wintertime when there’s so much less of it. We don’t normally think that way in California, but occasionally a higher SHGC can actually help, especially on the East wall. The reasoning is that solar energy on the east, when the sun is just rising, can help the house to recover from cooler nighttime temperatures.

Typical test results from Fleetwood Windows, available online, show just how many options there can be even within one product line.

The Title 24 prescriptive minimum for window performance is .40 U/.35 SHGC, lower being better for both these numbers. That’s pretty tough, considering that most ordinary metal framed windows run around .50 or .60 U factor, even for double glazed, “Low E” glass. We had started with the generic “metal double glazed low e” input which is around .65/.40. This project specified Fleetwood windows, which has several product lines with a wide array of options for glazing, thermal breaks, gas fills, and even glass types. All of their test results are easy to find, too.

We also modeled each window opening separately (over 77 of them), so that we could use different performance numbers for each window type: there were Casements, Awnings, Fixed, Sliding, and a couple of custom settings. That way if a better performance could be had from the fixed windows but not from the operable ones, we could include it. Sometimes clients have also asked us to use different settings for different cardinal directions, for example, using a more expensive but spectrally selective glass on a western or southern wall where it might matter the most.

For the Swatt|Miers design, Green Compliance Plus modeled over 70 different glazing areas in order to account for small performance variations among window types.

U Factor or SHGC – Which Is More Important?

Although we were more concerned with the U factor, it was possible that testing different combinations of U and SHGC factors might yield some interesting information. So, we spent a lot of time trying very low U/low SHGC combinations. We also tried some average U with very high SHGC windows, as well as trials where we kept one number the same and varying the other one up and down to see what would happen.

A low U factor was the best choice, regardless of SHGC – but, this might not be achievable, even if they used the more expensive, thermally broken frames. Of course, triple glazing with argon gas fill would help a lot, too – I’m not sure what the quote was for 4,500 square feet of windows with triple glazing/argon/thermal breaks, but it would have killed the project budget. We had to find some way to make it work with double glazing.

A U value of .35 or under would be better overall. A U value of .25 would be awesome. If the U value was low enough, like .30, it didn’t matter as much what the SHGC was. In fact, with a U value of .25 some of the runs came out almost 40% over compliance! Some interesting window results: With a higher U value, a moderate solar heat gain acted to compensate somewhat for heating loss. It was almost as if there existed a second, smaller “peak” of outliers which, if I had a lot more time, I’d try to graph in more detail.

Of course, it’s all very well to say that we need a window with a U value under .30. The U value was the one thing that most limited us, because with the window products and framing materials selected, it simply wasn’t possible or cost-effective to get down that low. And, specifying an artificially high SHGC just to “make the numbers” didn’t make sense. But then again, neither did specifying triple glazed, argon filled windows in a mild California climate zone.

Custom Window Wall

The custom window wall on the South wall was another challenge. Fortunately, this area was wood framed – not aluminum like the rest of the windows. The wood framing would help with thermal performance, and the plans already called for double glazing with Low E glass. However, since there were no formal NFRC test results for it, what numbers could we safely assume for performance? As it turns out, we checked with the local Planning department for the project’s location, and they indicated that using the Title 24 prescriptive standard, .40 U/.35 SHGC, would be acceptable. This standard already assumes a wood framed, double glazed, low E glass window – so it made sense to use it for the custom window areas.

We might not be so lucky in another jurisdiction, though. The plan checkers have some leeway to use their own judgment and, if we’d been in another area, we could have been asked a lot more questions about materials, glass types, etc. – and possibly we might have had to use less forgiving numbers.

Additional Measures

In the actual project, we tried a few more things. One was a super-efficient water heater. Most water heaters are in the .65-.80 range for energy efficiency, but there are some out there that go almost to .95, so by creatively assuming that they would use the best systems available, we could at least present that as an option for compliance.

We called out each area of interior exposed thermal mass – exposed stone, tile, and concrete – because usually this helps with Title 24 calculations.

And, as a last resort, we could have called for some HERS verifications for extra compliance credit. Our article on HERS testing describes each of these tests in detail: duct blaster, blower door, QII, and various tests on the A/C system. Of course, not all these tests were available on this project. With radiant heating and no A/C, there were no ducts to test. And, the various A/C tests – refrigerant charge, fan watt draw, airflow, and verified EER – couldn’t be used, either.

Would Cooling Be an Issue in the Real World?

Initially we were surprised that cooling was not a problem, and we were all wondering how realistic that would be once the house was actually built and inhabited. Title 24 intentionally ignores some real-world conditions such as landforms and shade trees, but it does apply location-specific climate data on top of the broader “climate zone” designation. The designer expressed concern that with a high SHGC window, the house would be too warm during the summer, especially along the South side. And really, to us it didn’t make sense to use an artificially obtained number when the most straightforward thing to do would be to use California standard Low-E, low SHGC glazing.

Would Philip Johnson’s Glass House Meet Title 24 Energy Requirements?

Just for fun, I did a quick test of Philip Johnson’s Glass House, using floor plans and dimensions that I was able to find on Google… no guarantees on accuracy, but it seemed like it was worth a try. The trials included three California climate zones: Woodside (Zone 3), Tahoe (Zone 16) and Livermore (Zone 2) and a few compass orientations for 0, 45, and 90. For starters, I assumed double glazing and Low E glass, with the same numbers as a wood frame would be. And, for heating I assumed radiant heated slab flooring… which I think is the actual method.

Title 24 ignores shade trees, which in the case of Philip Johnson's Glass House are a major environmental feature.

The compass orientation didn’t matter that much – it mattered a little – but, the location had a bigger effect, mainly in the balance between the shortfalls between heating and cooling. No surprise, Livermore had the biggest cooling problem initially.

Setting the glazing to something more like the actual (metal framing, clear glazing) was disastrous for Title 24 compliance. However, when I changed the windows to the “best available” performance numbers – something around .20 U/.20 SHGC – the house complied in all three zones without any further changes.

I've never been inside the actual Glass House. I wonder how comfortable it really is in the winter? There are almost no wintertime images of it.

The Catch – Custom Built Windows Can’t Use NFRC Test Results

In reality, it may not be possible to even obtain pre-manufactured windows of the size that are used in Johnson’s Glass House. And, in order for performance numbers to be valid and acceptable for Title 24, the window units have to be NFRC rated. We’ve discussed this in a previous article, so I can’t assume that the Glass House design as it is now would ever be able to fully comply with Title 24. And, of course, the Title 24 modeling software only has climate data for California, not Connecticut where the house is actually located. Nonetheless, it could comply a lot more easily than some other projects we’ve worked on.

Another Glass House: Olson Kundig’s Glass Farmhouse

As I was looking around for any accounts of the actual comfort of Johnson’s Glass House, I found another, much more recent take on the all-glass house from Olson Kundig Architects, located in Oregon. Alas, no reports on actual energy use or comfort here, either – but Kundig did employ solar design features and high-performing glass and took some care to adapt the house to the local climate. You can see some nice images and a description at The Contemporist.

One of our Title 24 clients, Okamoto Saijo Architecture, recently completed a  $50M retrofit that included creating a 900-kW PV system that is currently one of the largest affordable-housing solar installations in the world. We interviewed one of the principal architects, Eric Saijo, about how the Crescent Park project went from his perspective. He was actually quite happy with the outcome, and after 4+ years of budgeting, negotiating with utilities, the project is completed.

Crescent Park, an affordable-housing solar retrofit by Okamoto Saijo Architecture.

How were you selected?

In the last 12 years we’ve done lots of affordable housing rehabilitation projects. In this day and age people get put into certain categories. We’ve developed a reputation.

Eric Saijo and Paul Okamoto of Okamoto Saijo Architecture, at one of their own project sites

It’s less glamorous, but that’s OK. This client had been working with another architect and the project got put on the back burner for half a year. In 2005, they came to us. We spent 2 years in design and documentation to figure out the project scope.

How was scope determined?

Identifying the budget is always a challenge. They had a wish list of many items, including PV for 100% of electrical needs. We did feasibility studies to analyze whether they had the budget for all the things they wanted to do: update kitchens, flooring, waterproofing. The solar portion was only one aspect.

You did a lot of analysis in addition to design.

We worked hand in hand with our contractor (Brandon Slater of West Coast Contractors) from Day 1 on pricing and budget.

What would you do differently next time?

A better question might be what have we learned? Let’s talk about this instead. We learned more about handling the specific challenges of pulling off a PV installation in a 40-year-old multi-building complex.

Okamoto Saijo Architecture has done "green" private residences as well as sustainable public housing.

We started off with plans for 100% of onsite electrical needs generated by PVs. Our solar engineer did a layout showing where we could put panels on all roofs, taking tilt and orientation into account for each building. We also had an idea of the number of kWh that we needed to generate. Then we could look at all the other constraints.

What were the other constraints?

Not enough roof area on the existing buildings, and existing building systems that were not designed for the structural loads of the panels and the installation process.

Are solar panels really that heavy?

No, but retrofitting existing buildings triggers all sorts of re-analyses, and one of these is to re-analyze for seismic load. Any building that’s 40 years old won’t pass today’s seismic code requirements. And any increase in load over 5% triggers this seismic analysis… it’s a huge limiting factor.

Most PVs get installed in a design-build fashion.

When installing panels, there should be no live load on the roof where the panels are… adding even a minuscule amount of weight can be a problem sometimes.

What was the problem with retrofitting to use existing equipment?

How to make the most of the existing electrical service equipment in a retrofit! The simplest thing to do for an individual building is to install a large PV system and replace all the service equipment and tie in the PV to the entrance panel breaker.

Connecting those beautiful photovoltaics to the public utility's metering and grid system can be a "non-trivial exercise".

The electrical code is written in such a way that PVs are considered a “load” meaning that you might have to up-size the service equipment. The secondary field lines from PG&E, with extra runs to each building, for 24 buildings on 6 acres… this becomes a huge cost.

However, the electrical code does allow for line-side tap between the meter and the main shutoff switch. The equipment is now 40 years old which the code still allows, but it is physically difficult to implement line-side taps. We had to persuade PG&E and the head building official to conceptually approve it.

The larger buildings had enough space in their service equipment to clamp onto existing conductors when we needed to do that. We had to modify the charge condition meter main shut off and route it through a new gutter. We could do new tap here. and then clamp to conductor.

UL certification was another issue. The existing equipment, being 40 years old, wasn’t UL fabricated. Small enough to service meter and switch board were separate pieces of equipment. When the contractor, the electrical building inspector, the electrician, and the solar engineer got together – it was a tense moment!

When architects and building inspectors meet…

The next challenge was getting our systems approved by PG&E. You have to get approval from your local utility in order to submit for solar tax rebates. A 900 kW system like this one must undergo review at PG&E’s engineering department. They analyze their own infrastructure, including their transformers and underground conduits. In this case, PG&E’s equipment was also 40 years old, and perhaps built to prior standards. It took them quite awhile to analyze our proposal.

At first, they rejected it and wanted us to pay to upgrade all the transformers serving the complex. This was due to a loophole in the agreement for rebate systems for PVs, which allow the utilities to charge the client for these upgrades.

But if the power is generated onsite, why do you need those transformers?

In the middle of the day in a residential complex, power will be flowing out towards the grid. Changes to the photovoltaic systems had to be calibrated on the utilties’ side as well as ours. They had to change their meters so they could spin backwards.

Is that a smart meter?

No. A smart meter is one which is read remotely. [Communication is essentially what makes a smart meter more intelligent than a dumb meter]

Does PG&E do enough to support people like you?

There are people in various departments who did. The engineers really got behind us and worked with us to MAKE it work. Then there are other departments. All of them get delayed for a number of months without clear explanation. It could just be under-staffing.

Here’s an example of the type of problem we had to solve together with PG&E engineering… in one area of our project, there were 5 buildings served by one transformer. At first the told us that we had to pay for a new transformer, as well as pay for new primary and secondary feed lines – this would cost $200K.

Naturally our client wasn’t happy. PG&E countered that they were concerned that the kW would bump up the voltage above what they’re legally required to keep it under. Then they said, “But.. if you set the trip point on the inverters down, then we’ll approve.”

Inverters are normally set to 132V and they wanted us to set them at 127V. The PG&E grid is 120-122V but it just happens to be high in this particular location. As we installed systems in those 5 buildings, the inverters started to trip off. We’re still negotiating with PG&E over what to do.

What would you do different?

I wouldn’t accept a trip point! It was a sign that PG&E has real concerns about its own systems, that they were worried about the potential for voltage to increase too high . Our solar engineer had never run into that before. It was a real learning experience!

Even a genius can have a learning experience.

At this stage, our client didn’t know yet how much financing they could get. The budget was still in flux, and they really weren’t willing to accept sudden new costs. Especially in large renovations, you have to hold a large contingency fund; with our project, those funds are now available for post-construction.

What do the residents think about it?

Affordable housing is a very complex thing in our society. These are extremely low-income people. I didn’t have much contact with them but my sense is that they are appreciative of the renovations that included window replacement and other building improvements which improved their comfort and quality of life.

Another affordable housing project from Okamoto Saijo Architecture, PositiveMATCH is an adaptive re-use of a historic building in San Francisco, serving women with HIV and their children.

The buildings were made more airtight, with better insulation, new windows. And… cleaning the duct work after 40 years most likely improved the air quality.

Drainage for the entire site was improved. It’s very close to the Bay, with a high water table, so flooding is a concern. The storm drains were constantly backed up prior to the renovation, and ground floor units had water infiltration. All of these measures made the units more comfortable.

Another private residential design from Okamoto Saijo Architecture, a passive-solar farmhouse in Napa, CA

We also worked with the client to improve the visual appearance of the buildings. New paint schemes, and individual colors for each building. Before that, all 26 buildings on 24 acres had been colored the same. How monotonous!

Of course the resident’s don’t pay their own electric bill. That’s usually the thrilling part for homeowners is seeing their utility bill reduced. In this case, our client financed the PVs because they also pay the utilities.

Financing was through bonds. Our client was not the original developer. The project was originally built by a market-rate developer together with HUD. Our client bought it later, around 20 years ago.

When I first ran the numbers on the new Title 24 project from Klopf Architecture, the numbers were so high – 50% over compliance – that I immediately assumed that I had made a mistake somewhere in the calculations. After an internal review, however, we realized that it really was one of the most efficient projects we had ever taken through the energy compliance process. How did they do it?
Turns out that John Klopf, whom I’ve known through the AIA-SF Small Business Committee, is a huge fan of Eichler homes, and so were the clients who commissioned this new home in Cupertino, CA. They found Klopf through the Eichler Network, which is an online community “dedicated to supporting the lifestyle of the nearly 11,000 homeowners in Northern and Southern California who own an ‘Eichler’ home.”

Eichler homes, which were mass-produced tract homes designed by top-flight Modern architects, are highly prized today among fans of Midcentury Modern and California Modern architecture for their distinctively contemporary features – spartan simplicity, clean lines, open floor plans, post-and-beam construction, concrete slab floors with integral radiant heating, and integrated outdoor and indoor spaces.

Architect John Klopf, AIA

“Eichler homes are fun to renovate,” says Klopf. Eichler was unusually egalitarian for his time – non-discriminatory housing policies weren’t the norm at that time – and he made quality California Mid-Century Modern designs accessible to people of relatively modest means. “The homes employ limited technology, but are still relatively comfortable. Today, Eichler homes offer tons of potential as green projects, because their energy performance can be easily improved by affordable measures such as improved insulation and replacing the original clear glass with high-performing windows in the floor-to-ceiling glass walls.”

The owners are a high-energy couple with two young children who needed more space, more flexibility, and to remain in the highly-ranked Cupertino school district. Their desire to continue the Eichler aesthetic in their new home led them to John Klopf, who is widely known for his respectful work with Eichler homes.

However, the new home would be situated in an area of midsized 1960s ranch homes, on a small cul-de-sac where at least half the residents are retirees. They didn’t want it to stick out. So, the front aims for a “typical” suburban ranch feel with only a bit of modernizing. The client selected a cement fiberboard siding in horizontal planks, Artisan from Hardie, that is energy efficient and termite-resistant but which nonetheless blends well into the neighborhood. Then, as the view moves towards the rear, the Modern portions shine forth with a wall of glass at the rear. All that glass makes the home’s efficiency all the more amazing.

How did you design this home to be so efficient?

John Klopf responded, “We started off with a proper solar orientation. The home is designed to stay as cool as possible without A/C, because the client did not want A/C. Then we made the west wall mostly solid, without windows, with the exception of one portion of the western wall that featured spectrally selective, ultra high performing glass.”

“On the north wall, we used floor to ceiling windows to let in lots of light. This helped with stack-effect cooling as well. We kept the south facade relatively closed, with punched windows. This was not only for energy performance, but also to keep the front of the house in keeping with the ranch-style homes that surrounded it.”

Other basic energy design measures included 2×6 studs instead of the standard 2×4, in order to fit more insulation into the walls. “A lot of it is just using good quality construction, which should be what we’re doing anyway,” said Klopf.

Solar features include a giant sloping roof to the south, always intended for a big solar array, using solar hot water for radiant heating, and solar thermal. “We haven’t gotten to the interiors yet, so interior air quality is still ‘up in the air’. There’s no carpeting, which will do a lot to improve indoor air quality, and heat recovery ventilation systems will also help with air quality.”

Geoff Campen, another designer at Klopf Architecture, added, “Our contractor Phil is very into sustainability. He really helped us out a lot.” This was Phil Carey at Starburst Construction, a Certified Green Builder who’s well-known in the Cupertino area.

“Also, the client is VERY interested in sustainability, very adventurous. He likes to try out things that could work, even if they don’t have much precedent. He’s willing to take risks and make sacrifices. He’s open to the possibility of it not working quite as expected,” observed Geoff. “He asked us to look into SIPs and ICFs, was interested in solar PVs and water heating. We even considered gray water at one point. What we did was we walked through the GreenPoint Rating system with him, with the idea of doing everything possible.”

How does the client feel about the design?

“The house will be more than triple the size of the previous structure,” the client says, “yet it will use far less energy and it will not be a looming monster home out of character with the area. The beautiful modern design and advanced technology are well integrated into the neighborhood. We’re very happy with the plans.”

The client confirms that “the neighbors are very pleased with the look”.  “In fact,” he says, “it seems the only comment the planning department received was an email that said “I approve!”.  That was sent by a neighbor who is a big supporter of PV, hybrid cars and social change.  But the more conservative neighbors seem impressed as well, and may for the first time believe a greener lifestyle could be a reasonable and practical choice.”

How did the contractor influence the design?

Did he advise you on things like window placement? “It wasn’t so much about design as working out the mechanical equipment. Phil is actually a Certified Green Builder, with a lot of experience. He advised us on what was possible or not possible. Some of the GreenPoints are for use of certain materials, some of which are harder to obtain in California,” said Geoff.

“We started working with the subs like Solar City early on, and they provided the schematics for their systems.” These consultants included the solar, mechanical, and the landscape architect – and you guys [Green Compliance Plus] for the Title 24. There was no need for a lighting consultant, because the Eichler style calls for simpler lighting.”

Our discussion veered into what green building meant. I mentioned Green Compliance Plus’ recent Jeff King interview, and Geoff agreed. “Green Building is about living simpler, really, and less being more. But the flashier side can serve more as a mechanism for social change.“

John Klopf was more emphatic. “Sustainability is not a part of architecture. Architecture is a part of sustainability.” So what does this mean?

Even the experts don’t always agree on what “sustainability” itself really means. Klopf actually has several definitions of sustainability on pages 9 and 10 (PDF 17 and 18) of his report on sustainability for the University of California Merced Campus, available on his web site under “Research”.

Most “green” practices today are focused on mitigating degradation by incremental measures: slowing pollution, reducing toxins, increasing reuse. More ambitious approaches to sustainability actually seek to enhance the Earth’s carrying capacity by eliminating the concept of “waste” altogether.

But then there’s the practical side of what actually gets built, how it gets built, and with which materials.

When researching new materials like Structural Insulated Panels (SIPs) or Insulated Concrete Forms (ICFs), Geoff stressed the importance of selecting vendors with some financial stability. And, the best people to provide practical, useful information about these things are not the vendors – it’s the contractors.

“For one thing, not all SIPs are seismically approved for California. For another, it changes some of your construction methods for the trades. How the subs cut into the material to lay their systems is different with SIPs. When you install them, you have to cut every piece by hand.”

ICFs – Insulated concrete forms – are cast in place concrete, but the forms are left on. They have rigid insulation inside and out. The builder can attach sheetrock to the inside insulation, and apply a special waterproofing treatment to the outside. Do ICFs cost more than conventional building materials? “Well sometimes. But you might save on labor because these products are modular, pre-manufactured, and quicker to install.”

When’s the project going to be completed?

“Assuming the permitting goes smoothly, it should be done by the end of 2010″.

How are Planning and Building officials responding to the project?

“They’ve been very helpful, because they see that we’re serious,” said Geoff. “They’ve supported the project by making it easier to get variances on roof heights (for the solar), and they’ve moved everything very quickly.”

How does Cupertino feel about GreenPoints?

“In Cupertino, a GreenPoint checklist may be required, but you can hit the 60-point minimum without even trying. We’re at about 270 points right now,” Geoff responded. Klopf mentioned that Cupertino will pay for a GreenPoint rater to come out, as long as the home scores at least 75 GreenPoints. Since all submittals now need to include a GreenPoint checklist (not the same as an actual GreenPoint rating, which takes place after the house is built), theoretically the owner would know in advance how their GreenPoint rating was likely to pan out.

Are the clients doing home automation?

The clients didn’t want a fully integrated home automation system, but they are doing interesting things such integrating spectrally selective “smart glass” into the extensive glass walls along the rear of the home. Geoff adds, “They focused more on the relationships between spaces. One of them is an artist with a home studio, and she wanted to be able to watch the kids as they played or did homework in other parts of the home.” The other client requested more isolated spaces for a media room and a quiet but sunny home office. Klopf’s design team was able to meet all of their goals.

Interior of home

“This process has been as good for us as for the client,” Geoff continued. “At my last firm, we designed $10-$15M homes, but those clients were just not as committed. They’d say, ‘Oh, can it be green? We want solar’ without really understanding what that means. And, when they realize that sustainability means they can’t have those exotic finishes that have to be shipped from across the world, they abandon the green. It’s just not that important to them.”

By contrast, in this project, the clients’ commitment to green was the vital enabling factor in this project. “He’s a marketing consultant for high-tech companies. He’s also very into ham radio, has huge antennas at his home. He has a good grasp of engineering, knows a lot about building… this client was willing make sacrifices that in turn helped us get more into the project. We’ve never been able to engross ourselves in a project to this extent. With this experience, and the added credibility, we’ll be better prepared to push it in other projects.”

The client agreed, adding, “I think with this design we’ve managed to prove that a highly efficient, very green home can fit into an average suburban neighborhood quite well, requiring no uncomfortable sacrifices or anything that might seem like an eccentric lifestyle to the average neighbor.

“As the authors of Break Through argue, long-term environmental goals are more easily achieved when you can appeal to practical and immediate concerns like people’s wallets and their country’s energy independence, not by asking them to give up their lifestyle and get all crunchy just for the sake of the polar bears.”

“We’re very lucky that the client shared our passion for green design,” Geoff said emphatically. “The client’s commitment was the key. And, he’s savvy. We don’t have to teach him, we just have to meet and work things out.”

A principal in a local architectural firm approached us for T24 on a new house in Sonoma County that he was designing for himself and his partner. They needed Title 24 documents for their permit submittal, but beyond that, he wanted to qualify for solar rebate credits through California’s New Solar Homes Partnership Program (NSHP). He also wanted the house to be as “green” as possible, just because.

What do we need to do to get a rebate through California’s New Solar Homes Program?

Part of qualifying for California New Solar Homes Partnership Program (NSHP) is that the home’s Title 24 must exceed the baseline by 15%. As it turns out, the New Solar Homes Program has two tiers. Tier 1 is 15%, and requires Energy Star appliances. Tier 2 is 35%, requires Energy Star appliances, and you must demonstrate a 40% reduction in cooling load, presumably recovered from solar energy.

Well, the two buildings together were 15%, not 35. The main house was passing with flying colors, but the guest house was just squeaking by. So the question was, whether and how to modify the design aggressively enough to qualify for the higher Solar Homes tier. Since NSHP is tied to Title 24, there was some confusion over which features counted in which program.

Lessons Learned

Photovoltaics don’t count towards Title 24, but solar hot water does. However, using Solar Water Heating yields only small gains in the Title 24 results, not enough to make a difference in the Solar Homes incentive. Even without regulatory gains, though, adding solar hot water is relatively inexpensive, while PVs for electricity are not.

We also noted that the Solar Homes incentive has diminishing returns in the upper tier, because photovoltaics are expensive to buy and install, and can take many years to yield meaningful savings. Photovoltaics do count towards the solar credit, at $2.50 per watt, or 1500 watts for $3750. An additional incentive of $3.50 per watt or another $5,250 is available if you go for Tier 2. So, a Tier 2 home with 1500 watts of PV paneling would get a $9,000 rebate. But… it would cost $18K for the panels, plus installation.

Do we need a HERS rater?

When specific items are installed (Ducting, Solar P-V, certain EER-rated equipment etc.), these must be verified by a HERS rater who is a certified inspector with CalCerts, CHEERS, etc. When you have solar water heating or photovoltaics, it must be verified by an inspector who is specifically approved for the California New Solar Homes Program (aka “Title 24 HERS rated”).

What appliances count towards this credit under Energy Star?
Windows, heaters, lighting, fridge, freezer, dishwashers, washers, and dryers can earn Energy Star. Water heaters can be rated as High Efficiency under the Energy Star system, but they don’t “count” here towards the NSHP credit.

Where do Energy Star appliances get factored in for Title 24 compliance?

Umm, nowhere. Don’t confuse Title 24 calculations with the NSHP incentive. However, EnergyStar appliances count for plenty of other things – LEED for Homes, GreenPoints (which is strongly encouraged in some jurisdictions). And, of course, they contribute towards lower energy bills.

How much do you want to spend to improve the design?

Generally, adding more thermal mass, using fewer square feet of glass, using ultra low E glass, and adding a thermal envelope will all contribute towards improved energy performance, and all of these items are factored into the Title 24 calculations. But get it in before August 1, when the 2008 Title 24 requirements go into effect that are 15% more efficient than the old Title 24. With this added restriction, the main house would still comply, but not a 15% anymore, and the guest would not pass.