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HERS Inspections and Title 24 Compliance

HERS Inspections and Title 24 Compliance

Posted on 12. May, 2010 by in Air Leakage, Heating and Cooling, Interviews

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A few months ago we published an interview with a GreenPoint Rater to de-mystify the GreenPoints system that was suddenly taking California building departments by storm. Like LEED and several of the current rebate programs, GreenPoints has tie-ins to Title 24′s energy compliance scoring, and so we’ve had to help our clients to interface with this new standard.

There’s another standard that’s been around for a long time – the Home Energy Rating System, or HERS. For the first time, we are having to tell our clients that they will have to do at least one HERS verification in order to meet the new 2008 standards of California’s Title 24 energy code. Suddenly, everyone had questions. What in the heck do HERS raters actually do, and what does it cost? Is this going to be a huge headache or a minor annoyance? What benefit is there to HERS testing apart from compliance? What does a person have to do to become certified as a HERS rater?

I’d make a distinction between green-building standards and energy performance standards.

  • Green building is focused on the bigger picture, on quality of life, and on the entire life cycle of the building and possibly the surrounding community. Examples include LEED and GreenPoints.
  • Mechanical/efficiency standards are focused on building operational performance and energy usage. In this context, the Home Energy Rating System, or HERS, falls into this second category.

What HERS raters do is make your home more energy-efficient by auditing its current performance levels and pinpointing areas of poorest performance. A few weeks ago, I looked at the CEPE roster shared by the California Association of Building Energy Consultants (CABEC). I was looking for people with dual or triple credentials in GreenPoints, HERS, and as a Certified Energy Plans Examiner (CEPE), since those are the three areas where we most often have to interface with our Title 24 work. One of the people listed on that site, Rob Lehman, is the subject of today’s interview. Rob is also listed on our Affiliates page.

In the text below, Rob’s answers are credited as RL, and editorial notes are shown as [bracketed italic].

What do HERS raters do exactly, and why is it important?

RL: HERS raters are special independent inspectors certified through a HERS provider, and ultimately by the California Energy Commission (CEC) to evaluate homes in California according to the Home Energy Rating System (HERS). These ratings include field verifications and diagnostic tests to determine existing efficiency levels for various energy-consuming components such as:

  • Heating and cooling systems
  • Supply and return air ducting
  • Building envelope air infiltration
  • Building envelope insulation quality

A HERS rater will also perform a comprehensive energy analysis of the home, including energy consumption for all daily living activities in the home. This evaluation includes the heating and cooling systems, and how the building components such as insulation, doors, windows, water heater, and lighting all affect the home’s energy efficiency. The information is entered into a computer program that calculates an energy rating for the home. All of the possibilities for improving energy efficiency are analyzed and prioritized according to which ones provide the most improvement relative to their cost.

home energy loss percentages HERS Inspections and Title 24 Compliance

This illustration shows where the bulk of energy loss occurs within a typical home: 40% through the roof, 36% through the floor, 14% through the walls, and the remaining 10% through window and door openings.

[HERS is nationwide, not just California. The California HERS program was implemented starting in 1999, and is used provide field verifications for energy efficiency programs. HERS Phase 2 or HERS II is the next stage in that implementation within the state of California. There is also a national HERS program sponsored by the Residential Energy Services Network (RESNET).]

How did you get into this work?

RL: I became interested long ago in do-it-yourself energy conservation and efficiency through Mother Earth News way back in the 60′s and 70′s, and dreamed of a day when smarter building methods would actually be used to conserve energy and help to save the environment.  When I realized the opportunities were out there to become a HERS rater, I joined right away. I have always dreamed of having an active and productive part for myself in energy and environmental conservation efforts.

Where can people find a HERS rater?

RL: People usually come to me through their builders. The public hasn’t caught on yet where to ask for Home Energy Rating Systems inspectors, but you can find HERS professionals listed on sites like CABEC, or through one of the three registered HERS provider organizations within the state of California:  CHEERS, CalCERTS, or CBPCA.

For our market space – residential low-rise Title 24 – what are the most common verifications solely for Title 24 compliance?

RL: The most common HERS verifications that I have performed for low-rise residential construction include tight duct tests and Quality of Insulation Installation, or QII. That’s my advice – start with the ducting and the building envelope.

blower door HERS Inspections and Title 24 Compliance

A blower door test measures the amount of air infiltration within a home.

Some other HERS verifications that are also good to do, and which earn compliance credit within Title 24, include:

  • Blower door test for air infiltration through walls, ceilings and floors
  • Refrigerant charge management and verification in split system air conditioners and heat pumps
  • Measurement and verifications in a/c cooling coil airflow
  • Measurement of air handler fan watt draw
  • Verification of high energy efficiency ratio (EER) for the air conditioning system, through component matching
  • Visual inspection of supply duct location, where ducts are located within conditioned space
  • Visual inspection to verify buried ducts or deeply buried ducts
  • Photovoltaic installation verification

To qualify for Title 24 compliance, all of these measures require a certified HERS Rater to conduct a field test or visual inspection, and register the results with a HERS provider.

[A HERS provider is not a person, it's an organization such as CHEERS, that is certified by the State of California. You can earn compliance credits through HERS verifications if you use the performance method of Title 24, which employs a software model to simulate the building's energy performance.]

As time goes forward, I believe that people will have to use HERS verifications more and more, as a bolstering measure for Title 24 energy compliance. They will need the extra credits from the HERS verifications to obtain the Title 24 performance scores necessary for green building certifications such as LEED, Build it Green (GreenPoints), and Energy Star.

Are you finding that it’s harder to get projects to comply under the 2008  Title 24 code? What sort of measures are you having to advise your clients to take?

RL: Numerous changes within the 2008 Title 24 energy code have raised the standards for higher energy efficiency in California homes to roughly 15% above that of the 2005 energy code.  And this is just to obtain a passing score of “0″. All this is being driven by AB 32, the Global Warming Solutions Act of 2006. The State of California will continue to tighten up requirements in future code cycles, which happens every 3 years.

I advise my clients to take advantage of the HERS verifications that will help them the most, within their climate zone. In San Francisco, there isn’t a tremendous demand for cooling such as there is in Fresno. So perhaps instead of recommending a refrigerant charge management test, I might recommend a blower door test for whole house air infiltration, to identify problems with a poorly performing building envelope.

ca climate zones HERS Inspections and Title 24 Compliance

California has 15 climate zones, each with different heating and cooling loads. For example, San Francisco is Zone 3, San Jose is Zone 4, both relatively moderate. Livermore, which isn't that far away, is Zone 12 - much hotter.

I have found that including even one HERS verification yields a very significant improvement in the Title 24 energy report score. If the client plans on obtaining a green building certification through a program like GreenPoint Rated or LEED, a Title 24 performance score of 15% better than “0″ is mandatory.  Considering that the 2008 Title 24 requirements are already 15% tighter than before, plus the additional 15% over baseline required for Build it Green or LEED, it is easy to see that employing a HERS rater may be essential for achieving all these goals.

Compliance aside, what are the most worthwhile verifications or services that a HERS rater can do? Why would someone hire a HERS rater aside from Title 24 compliance?

RL: Saving energy! That translates into lower utility company bills, month after month. Everything that a HERS rater can do is an avenue for improvements that will save money. Here in the Bay Area, I recommend starting by investigating the building envelope and duct systems.

duct blaster HERS Inspections and Title 24 Compliance

A duct blaster test in progress. This duct lying on the floor looks a bit like a python at the zoo.

I recommend starting with the ducting because the standard methods of installation for HVAC ducting throughout the years has not been favorable to tight, efficient ducts that have low air leakage. I’ve heard figures quoted in training workshops stating that 30% leakage in a typical ducting installation is routine, and the air infiltration even in some newer homes is still very poorly controlled. That is a tremendous waste of valuable heating or cooling BTUs! All that expensive conditioned air could be going into the attic or under the crawlspace, or out through holes and gaps in walls, floors, and ceilings and not into the home where you want it.

That’s crazy! Are ducts really that poorly installed every time?

RL: Duct leakage is an issue especially in tract homes that are built by contractors working under the gun to finish the job as quickly as possible. Another problematic practice has been that the so-called “standard” for duct sealing for many years has been to use duct tape for sealing the ducting to the sheet metal connectors. But, most duct systems are in the attic, which get as hot as 140 degrees in the summer time. Duct tape adhesive isn’t designed to withstand these temperature extremes, and it dries out.

Articulated duct joint sealed with water based mastic HERS Inspections and Title 24 Compliance

Ducts, plenums, air handlers, and connectors should be sealed with mastic on all joints and seams.

OK, so tract homes are one thing, what about custom residences? Do they have leaky ducts, too?

RL: Even in custom-built homes with higher standards of care, it still happens. The standards say not to depend on duct tape, that instead duct mastic should be used. [Mastic is a high-strength flexible adhesive that can tolerate temperature fluctuations.]

duct sealing flex HERS Inspections and Title 24 Compliance

Don't use duct tape to seal your ducts - use mastic. There are plenty of web sites to show you how, although if you've never done it before, consult a professional.

What is Title 20 and why do HERS raters care about it?

RL: Title 20 is a piece of California legislation that empowers the California Energy Center to approve the software and protocol necessary for HERS II Raters to conduct energy audits, in order to tie those audit results more closely into various new incentives. There have been energy-auditing businesses and HERS provider organizations offering their services for years now, but until now they have not been regulated by the State. One reason to do so now is the increasingly complex interrelationships among the various energy-related incentives, rebates, and tax credits with Title 24′s energy compliance scoring system.

Title 20 is new legislation, very recently passed in California, which is now in the implementation stage. My HERS Provider, CHEERS (which stands for California Home Energy Efficiency Rating System) is within one month of being available to train and certify HERS II Raters to audit and report energy scores for various incentives, rebates, and tax credits.

Are there other pieces of legislation in the works that we should know about?

RL: Local government financing of homeowner energy improvements through AB 811 may require a HERS II Rater to perform various tests to show how much energy efficiency improvement has actually been achieved. The Federal Home Star Program may require similar verifications.

Rumors of mandatory energy score reports for real estate transactions when selling a home in California are probably not going to pass as law anytime soon, because there has been a lot of opposition from the real estate lobby.

What do general contractors and HVAC contractors have to do differently now under the new Title 24 requirements?

RL: If there are required HERS verifications for any portion of the scope of work involved for a permit, General Contractors and/or HVAC Contractors will have to hire a HERS rater who will register the HERS verification measures online in order for the contractor to obtain a building permit. This requirement will take effect October 1, 2010.  The documentation for the HERS verification (included on the CF-1R Title 24 report) must accompany the application for the building permit, and be submitted to the building department for that jurisdiction.

[These HERS verifications consist of whatever tests were called out originally on the Title 24 report also known as the CF-1R, which was submitted earlier to the planning department for site permit.]

In terms of the CF-1R and CF-6R connection, who’s responsible for what? Where is this all-encompassing HERS data repository, anyway? Who owns and maintains it? How can an architect look up the status of his or her project to see if the project was properly registered? If the HERS rater doesn’t follow through on the reporting, what does the architect have to do to follow up?

[Each registered HERS provider maintains its own separate online registry. Again, these providers are organizations, not people. There are three HERS providers in California: CHEERS, CalCERTS, and CBPCA. Ask your HERS rater which provider he or she is certified through to discover where your project will be registered, and check that provider's web site.]

RL: There are actually three compliance-related forms for Title 24 now: The CF-1R, the CF-4R, and the CF-6R.

  • The CF-1R (the Title 24 compliance report) indicates which HERS measures have been specified for credit in the Title 24 energy calculation. Both the architect and the project coordinator are responsible for knowing what is on the CF-1R in terms of how the building and systems are modeled, including specific performance data for products such as furnaces and windows, and any HERS verifications that are specified. The architect should communicate this information to the other parties for follow-up as the project schedule requires.
  • During the course of construction, the owner of the project, or his or her contractor, is responsible for ensuring a successful verification by a HERS rater for each measure listed on the CF-1R.
  • To prepare for each HERS verification, the contractor (general, electrical, solar, or mechanical) furnishes the HERS rater with a CF-6R, describing the portions of their work or installation that need to be verified. This could include ducting, an HVAC system or component, solar photovoltaic arrays, or insulation in the walls, floors, or attic.
  • The HERS rater is responsible for performing the verification and registering the results (pass or fail) with his or her HERS provider’s online registry within four days of performing the test or inspection. These results are also known as the CF-4R report.
  • The building inspector (building, electrical, mechanical) is responsible for collecting documentation certifying that the HERS verification is complete, approved, and properly registered before signing a final inspection.

What’s the best way to ensure that the tests happen at the right time during construction?

[The general contractor or construction manager should do the following:

  1. Make sure that they have accurate information about the HERS verifications that are required for the project, and
  2. Include both the HERS verifications and any pre-testing at the appropriate time in the construction schedule.

For example, the ductwork can be pre-tested prior to completion of construction, but it will be an extra task for the contractor to do so. Since most contractors do not own the duct testing equipment themselves, they may need to have another HVAC professional (the HERS rater can't do it) do some pre-testing prior to the "official" test, at a time when the ducts are accessible for additional repair if needed. However, if the contractor waits for the official HERS test and the ducts don't pass, they may have to pull off sheetrock in order to address and repair any deficiencies.]

Let’s go through each of the tests individually and describe what’s involved.

What happens during a duct blaster test?

RL: Also known as a verified air leakage test, a duct blaster test is designed to test and document the air-tightness of forced-air duct systems. It takes about 1 to 2 hours to do.

duct testing HERS Inspections and Title 24 Compliance

Why is it that the only photos I could find of duct testing all show men?

In this test, the HERS rater attaches a calibrated air flow measurement system directly to the duct system in a house, typically at a central return, or at the air handler cabinet. With the remaining registers and grilles temporarily taped off, duct air tightness is measured by either pressurizing or depressurizing the duct system and precisely measuring the fan flow and duct pressure. The findings result in a percentage of leakage for that system.

For new homes, a leakage of 6% or less is the threshold to pass. An existing home needs to achieve a leakage rate of 15% or less. In some older homes, however, the ducting system may be largely inaccessible for repair. For these cases, a 60% improvement after failing the initial test may be allowable.

air duct leakage tester machine HERS Inspections and Title 24 Compliance

This is an example of a duct tester machine that might be used for commercial buildings. This one is a PANDA 311 Series from TSI.com. It doesn't look all that scary.

To prepare for this test: inspect your ducts ahead of time. Do you see old duct tape? Any mastic used?

For architects or private homeowners doing remodels, where this test may be specified to achieve Title 24 compliance but where no work is actually being performed on the HVAC system as part of the remodel, how do we know it’ll pass and what can we do if it doesn’t?

RL: Have an HVAC contractor come out and inspect it, pre-test it himself. Then the HERS rater can come out and officially test it.

Are there situations where a house will NEVER pass a duct blaster test?

RL: Well, if you’re using the prescriptive method of Title 24 compliance, duct testing is a mandatory measure for additions with over 40 new feet of ducting. However, if the home has asbestos in the system, it’s exempt.

But let’s take another example. Let’s say that this test has been called out, and it’s an existing home, an older home, with an alteration that has triggered a Title 24 compliance report. Let’s say that we need to use the performance method for Title 24, because we’re adding too much glass. We needed the credit from the duct test to get a passing score on the Title 24 report back at submittal time. Now we’re in construction, and it’s time for the actual test. What if it doesn’t pass, even with a 60% improvement on the second try?

My answer would be that you can’t get even a 60% improvement, that means the ductwork is very poor and the homes heating and cooling will be extremely inefficient. The homeowner should consider whether he really wants to keep throwing good money after bad.

What happens during a blower door test?

RL: A home’s air-tightness is measured with a diagnostic tool called a Blower Door. The Blower Door consists of a fan that is temporarily sealed into an exterior doorway coupled with calibrated pressure measurement equipment. The fan blows air out of the house to de-pressurize the home. This negative pressure differential pulls air from outdoors in through any holes, gaps, improperly sealed penetrations in the building envelope, or locations where weatherstripping is loose or missing – to name a few.

Blower Door tests are typically performed at a pressure difference of 50 Pa (0.2 inches of water column) and the findings are measured in Cubic Feet per Minute (CFM). The CF-1R form (the Title 24 report) has the minimum and maximum allowable rates indicated, and the test must show a rate that falls between those figures.

To prepare for this test: Seal off all openings and drains. Close all the windows, put stoppers or plugs in the sinks and tubs, seal off range hoods and chimneys, and plug up any other hole you can find.

So how can you pinpoint where air is coming in? Is there any equivalent to the thermal image test for heat loss?

RL: Not really. But you should look for obvious signs first, like loose weatherstripping. Caulking can help. Thermal imaging won’t help except in some cases where windows may be leaking around the seals or frames. Today’s windows are manufactured with tighter control and they’re better performing with regard to air infiltration. However, window installation may be an issue. Look for cold spots around window openings if using thermal imaging.

cold air infiltration at window sill 540 HERS Inspections and Title 24 Compliance

Thermal imaging can be an aid in determining where air leakage is causing cold spots. However, you can't always tell what is causing a spot without further investigation. It could be air, moisture, or thermal heat loss.

For thermal imaging to work, you need to do it on a cold day so there’s a visible thermal difference between the interior and exterior temperature. Also, any cold spots you do see may or may not be due to air infiltration.

Why does the air infiltration rate have to fall between two numbers? Isn’t lower always better? Don’t we want to create an airtight home?

RL: A home can actually be too airtight as well as too loose. Some newer homes are so airtight that they can have problems with moisture buildup, which can in turn lead to mold.

I thought mold was mostly a problem in very humid climates, not in California.

RL: If the home is tightly sealed and it also has high-humidity devices such as spas, aquariums, greenhouses, or even if the occupants do a lot of cooking, it can develop serious mold problems, even out here.

What is an Verified Insulation Quality test?

RL: A Quality of Insulation Installation (QII) verification is a visual inspection by a HERS rater to verify optimal quality in insulation installation. The HERS rater verifies the following:

  • The insulation is of the proper R-value and type specified in the architectural plans and on the CF-1R Title 24 report
  • The insulation coverage does not have any voids or gaps, nor any compression where the insulation is restricted from achieving its full thickness
  • All pipes, wires, etc. that are in cavities where the insulation occurs are covered with non-compressed insulation in front and in back
  • All electrical boxes are carefully cut out in the insulation in order to provide a tight fit with no gaps or holes

In other words, the QII inspection is looking for the installation to be pretty much letter-perfect, so that the home performs up to what the insulation manufacturer is specifying for their product. The reality is that most insulation is installed by subcontractors who are seeking to finish the job as quickly as possible.

HERS rater insulation HERS Inspections and Title 24 Compliance

A HERS rater can verify that insulation was properly installed by checking that the right insulation product was used, and that the insulation was applied evenly, without gaps or compression.

This verification is more cumbersome and involved that most other HERS verifications, because the HERS rater might have to make several inspections as different parts of the building are framed. For example, under-floor insulation has to be viewed before the subfloor goes on top, wall insulation should be viewed prior to installing the drywall, and corner cavity insulation has to be viewed from the exterior.

Can you do this test using thermal imaging if the walls are already closed up?

[For the purposes of Title 24 compliance, the QII verification itself has to be visual, with the walls opened up. However, if you are investigating a home's energy performance, thermal imaging can pinpoint problems that would otherwise be invisible.]

vaulted ceiling all HERS Inspections and Title 24 Compliance

Thermal imaging shows missing insulation in this ceiling where it meets the wall - something that you can't see with the naked eye. In this case, what we're seeing is the building's cooling performance on a hot day, and the missing insulation shows up as a "hot" spot.

Where are the most common spots to find insulation gaps?

RL: In addition to the spots described previously – areas around electrical boxes, pipes, wires, and small building cavities – consider these areas as well:

  • Behind the tub or shower
  • Fireplaces and chimneys
  • Skylight window wells
  • Exterior edge between building floors
  • Interior/exterior wall connections

This last one is important and hard to get to. In places where there’s a connection between an interior and an exterior wall, there will be a three-stud channel that’s typically filled with dead air, and no insulation. A 1.5″ wood stud has an R-value of only 2 or 3, while the mandatory minimum is R13. Insulation is typically installed from the inside, but for these channels, you have to get to them from the outside.

How do you remedy uninsulated spots inside a wall channel?

RL: To remedy the omission of insulation in a wall channel, you have to address it as the carpenters are framing the house. For example, they could cut and install rigid foam insulation. During a QII inspection we’d have to come out and see this part as it occurred.

What is a refrigerant charge test?

RL: The refrigerant charge test is a HERS verification for split-system air conditioning systems, and ensures that the air conditioner has an adequate supply of refrigerant to work with. The amount of refrigerant in the system can dissipate over time through leaks, and if it gets too low, the system’s overall efficiency suffers, possibly even shortening the life of the system. If the refrigerant level is adequate, the system is considered to be fully charged.

There are three ways to verify refrigerant levels.

  • A non-intrusive test that analyzes the superheat and the temperature drop across the cooling coils, and compares that information to referenced values. With this information, the refrigerant charge can be calculated. It’s cumbersome to do because of the math, but worthwhile if you depend on your A/C system for comfort.
  • A more intrusive method, less frequently used, is to attach a simple pressure gauge to the A/C system to get a direct reading of the refrigerant level within the system. However, this method also requires the HERS rater to obtain a certification from the EPA, because if the refrigerant leaks out, it can damage the environment.
  • Within the next few years, manufacturers will begin installing a CID (Charge Indicator Device) with newer models. At this point, a simple reading of that gauge will be all that is necessary to verify the refrigerant charge. However, manufacturers have not provided these devices in most models as of yet.

Refrigerant charge verification is a mandatory prescriptive Title 24 energy calculation compliance in climate zones 2 and 8-15, but when running the performance method of compliance, it can be a selected HERS verification in all climate zones.

To prepare for this test: If you’re doing this test to meet Title 24 compliance requirements, you need to have a HERS rater do it. But, a pre-test can be performed by any HVAC contractor. If you’re not sure the home will pass, you can have an HVAC expert check the system first, and fix anything that needs attention, so that you’ll know the results of the “official” test beforehand. Because of their status as independent inspectors, however, HERS raters are not allowed to fix or change anything themselves. All they can do is run the tests and report the results.

I can see where a refrigerant charge test would be worthwhile for an older A/C system, but what about a brand-new one?

RL: Even with a brand-new A/C system refrigerant charge can be a problem particularly with split systems. In a split system, you have a compressor outside and a suction and pressure line running to an air handler inside. This line can be rather long, and if there isn’t enough refrigerant in the system, it can take enough to fill this tubing that there isn’t enough in the system overall.

OK, say you’re a developer, you want your latest project to be GreenPoint Rated, and to get more points you want to boost the Title 24 performance score on all the homes. To this end, you have opted to include HERS verifications such as the refrigerant charge test in order to gain additional Title 24 compliance credits. How would you go about pre-testing if you had a whole group of tract homes and you need for them all to pass the refrigerant charge test?

RL: In a tract home situation, an HVAC contractor can use sampling during pre-testing. The HERS rater will sample test also, in groups of 7. Bigger builders should realize that HERS raters are an asset that they can use to test and verify different components of construction.

What is a fan watt draw test?

RL: A fan watt draw test is done on air conditioning systems. It’s a simple measure of the energy consumed by the cooling coil fan, and referencing this to acceptable maximum values as shown on the Title 24 report.

What is a verified air flow test?

RL: This test measures the rate of air flow through the ducts. There are several ways to measure, but I am most familiar with the use of an air-flow capture hood, measuring the airflow with all registers open and the filter installed, and comparing the flow rates to be equal to or surpass the duct design criteria of 450cfm/12000 btu (1 ton).

What is an EER verification?

RL: An EER verification matches air-conditioner components for high functional efficiency as a group. This verification applies to split systems, where the air handler, the outdoor compressor, and the cooling coil can all be from different manufacturers. The verification looks up the make and model number for each of these components in a CHEERS online software application that contains data on how efficiently each of these components actually works with the others.

Is the EER verification a pass/fail test? What do you do if it “fails”?

RL: It’s pass or fail. What we do is match up the components for high EER compatibility. Either the proposed system makes it or it doesn’t. For example, suppose you have a system design that calls for a Carrier compressor, a Train air handler, and a third-party cooling coil. We do an EER lookup and it turns out that the off-market cooling coil was lousy pick.

At this point, you can remedy it in one of these ways:

  • Call the contractor and tell him that the components don’t match, and give him some other options that do match.
  • Re-calculate Title 24 report and pick another HERS measure based on what the project will best support.

How far off can they be in terms of efficiency if they’re not well-matched?

RL: I’m going to go out on a limb and give you a rough estimate, and say that mismatched components in a split system could degrade overall system efficiency by as much as 10-15%.

Is the EER verification something that you’d have to think about way ahead of time, during project design?

RL: Yes, this is something that should be considered early on. The architect or the mechanical systems designer should contact a HERS rater prior to specifying these components. It can stop you from making a bad purchase. Then, when you add this as a verification for Title 24 compliance credit, you can be confident that your system components can perform together as well as expected.

What is the maximum cooling capacity test?

[Usually recommended for commercial buildings. We're going to punt on describing it here, because it's rather complicated.]

What is the supply duct surface area reduction test?

RL: This is a verification measuring the efficiency of the duct design, again mostly done on large commercial buildings with very extensive HVAC systems. The HERS rater physically measures the duct system as installed and checks this measurement against the calculated allowable area of duct surface from the Title 24 report, and verifies that the existing duct systems meets this allowable criteria.

What are the visual field inspections that apply to duct systems?

RL: There are several inspections related to where the ducts are located and how well they’re insulated. All of these inspections are credits towards achieving a higher Title 24 performance score. The two buried-duct inspections only apply to ducts that are located in the attic.

  • Buried ducts: The HERS rater verifies that the attic supply ducts are buried under the required R-value insulation, and that the ducts make contact with the ceiling sheet rock. Signs must be visible that say “caution, buried ducts” [so that anyone doing subsequent work on the home doesn't inadvertently damage them]
  • Deeply buried ducts: In addition to the buried duct requirements as described above, the HERS rater verifies that the attic supply ducts have an additional R-25 insulation over them if fiberglass insulation is used, or R-31 for cellulose insulation.
  • Ducts in conditioned space: This test applies only to projects where the ducts are located in conditioned space, rather than in the attic or a crawlspace. The HERS rater does a visual inspection to verify that 100% of all supply ducts are within the conditioned space envelope.

[Radiant barriers, which can earn compliance credits in Title 24, are verified by a building inspector, not a HERS rater.]

Under what conditions would any of these tests NOT be advisable?

RL: The climate zone for each project needs to be considered to get the best bang for the buck. In other words, tests that focus on air conditioning may not be advisable in climate zones where there is little demand for cooling.

[They don't buy you as much on the Title 24 score, either. For example adding a radiant barrier in San Francisco does nothing to improve a home's Title 24 performance score, but adding one in Livermore or Los Angeles certainly does. ]

What happens if a project fails a HERS verification?

RL: The HERS rater has to submit the results to the HERS registry as a failure.  The necessary repairs should be done by the contractor, and then the HERS rater is called back to perform the test again.

When does each of these tests occur in the project cycle?

RL: Various stages. The important issue is usually to observe a complete and finished component for verification, prior to its being hidden by subsequent construction. One example is the verification of quality of insulation installation (the QII test), which may require several trips. Duct verifications are best done after all or most of the construction activity is completed, and there is no possibility of workers subjecting delicate items such as ducting to damage.

How much do these HERS tests cost?

RL: Well it depends in part on the size of the building and how cumbersome the test is to perform. A duct blaster test might start at $250-$300, because it can be done in one trip and it only takes a couple of hours. Some duct blaster tests are more challenging than others. A QII insulation test, which requires several inspections over a few weeks’ time, could be more.

How can the architect, owner, and builder ensure that the project will pass on the first try?

RL: Perform your own pre-inspections and employ expert help prior to the test date to prepare the components for testing. For example, good HVAC contractors will often test their own work anyway, although many don’t care enough about quality to do this. But, they should.

Compare it to smogging your car. Emissions is a state test, and it’s pass or fail. You can go to a mechanic ahead of time for pre-smog testing to find out if you’ll pass, and get any needed repairs done prior to having the official smog check.

What do architects need to know about working with local building departments?

RL: Their compliance review starts with the CF-1R form, which is the Title 24 compliance report. But most people don’t know how to read a CF-1R report. Even architects, building officials, and plan checkers don’t always know every aspect of compliance.

Building departments can’t interfere with HERS verifications, which is a State-level program. However, with the increasing levels of reporting and inspection, it will be harder to do last-minute equipment substitutions.

[One thing to note is that Title 24 reporting relies on specific stated performance criteria for products ranging from windows to water heaters, and any substituted product needs to have an equivalent or better efficiency rating. This means that the person responsible for selecting equipment and products must be fully aware of any assumptions that were used when preparing the Title 24 report for the project.]

Any famous last words?

RL: Here’s one thing you should know: All three of the official HERS providers are mandated to do follow-up inspections to check up on their own HERS raters. So, the homeowner could get a call or a letter notifying them that this is happening. Usually they’re OK with it, it gives them reassurance that the system is really working as intended.

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pix HERS Inspections and Title 24 Compliance About the author
 Rebecca Firestone has been working in the Bay Area since 1998 as a technical writer, business content developer, architectural filing lady, marketing director, and sorcerer’s apprentice.


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6 Responses to “HERS Inspections and Title 24 Compliance”

  1. Peter Clare

    01. Jul, 2010

    I am a homeowner who has been working on the energy footprint of my home for a couple of years now. This was a very helpful overview of HERS. Thx, P

  2. Ted

    20. Sep, 2011

    Thank you very much for this article. It is a great overview of HERS.

  3. Chip Escoffier

    29. Jul, 2012

    How can I get certified to do HERS inspections, I am a semi retired construction inspector with 30 years experience.

  4. Mark English, AIA

    30. Jul, 2012

    Hi Chip, you will want to get in touch with resent at:
    http://www.resnet.us/rater/What_and_How_of_a_Rater.pdf

    Good Luck!

  5. […] clients -and it’s good news for a change. The Quality of Insulation Installation credit is a HERS test that can help design projects to achieve Title 24 energy compliance, and we’ve had a couple […]

  6. Charles Crabb

    22. May, 2014

    Thank you for this article. San Diego people need to read this so they would know it’s for their benefit. It is a great overview of HERS Rater Title 24.
    Charles Crabb´s last blog post ..HERS Rating News on HVAC Stings and Large Fines

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