If your jurisdiction is adopting the IECC, and if you expect projects to use the ERI path, chapter 406, for energy conservation compliance. Or possibly you are looking to modify the rules or goals to accelerate the energy-efficiency or carbon reduction goals of your community? Then there are a few ground rules you should establish ahead of time, so everybody is on the same page.

Raters need to know exactly what was adopted, how special cases are handled and policies surrounding ratings. Below is a list of things that should be thought of before embarking on an adoption…

1. IECC code year adopted?
2. Adopt HERS or ERI rating?
3. If HERS, what is the required score?
4. If ERI, are test results required to be submitted?
5. If ERI, what is done if test results do not comply?
6. If ERI, what is done with mandatory items that do not comply?
7. What is policy, how do you handle atmospherically detached ADUs?
8. What is policy, how do you handle remodels?
9. What is policy, how do you handle additions?
10. What is policy, how do you handle off-grid houses?
11. What is policy, if scores at final do not reach the goal?
12. What is policy, in multi-family, is whole-building infiltration testing allowed? Or must units be tested for compartmentation?
13. What is policy, withhold the TCO & CO until the confirmed rating certificate is issued?

HERS or ERI… To boil it down, the main difference here is that a HERS ratings don’t enforce the IECC. Whereas the ERI version has the Rater checking for mandatory IECC requirements and performing the required testing. AHJs that are relying on Raters as an extension of their own inspection staff, need to have an understanding of what Raters are looking for and what they are not. For instance, a Rater has to perform their own pipe insulation inspection, but they would have no reason to check the vapor retarder, snowmelt controls or pools and spas. Even if a Rater inspects and fails an IECC item, it doesn’t necessary mean that information will automatically be transmitted to the building department. It’s possible that the pipe insulation might fail the Rater’s inspection and pass the building department’s inspection, or visa-versa. HERS ratings scores are always more flattering than ERI scores. And HERS ratings come with a colorful certificate that gives a dollar amount of estimated savings. HERS ratings don’t have any pass/fail thresholds, so their flexibility can easily be used for existing and non-conforming homes. A HERS rating doesn’t require any construction inspections, although the score will benefit if the insulation is inspected, and it turns out to be better than default, which is “poor installation, grade III”. The HERS rating score (not ERI) will appear on the RESNET Registry, which is the database for the MLS (Multiple Listing Service). So if you go with ERI, it will not match the score listed on the MLS.

ADUs and other kinds of out buildings… Ratings don’t deal well with attached or unattached ADUs, guesthouses, party barns, etc. I recommend making a proactive statement in your adoption about how these kinds of things will be handled. Ignore ADUs entirely? Make ADUs stand on their own additional rating? Just an infiltration test for out buildings, no rating?

Remodels and additions… When a Rater inspects a project with existing assemblies and unstickered windows, they must assume the worst. The project will have a hard time making a good score with existing assemblies holding them back. Raters cannot rate just part of a house and ignore part. I recommend additions would be allowed to submit prescriptively, or are required to meet a less stringent score than new construction.

Compartmentalization…  I recommend making a proactive statement in your adoption about infiltration testing in multi-family buildings. Whole-building testing of multi-family buildings has been permitted in the past. Whole-building testing does not test the party wall, corridor wall and floor/ceiling assemblies. If individual unit testing is expected, then make that very clear up front. Typically party assemblies are not designed to create an airtight barrier between units. The unit-to-unit air leakage will make every unit perform poorly on the infiltration tests.

TCO before Confirmed rating…  It would be good to have a policy on whether or not projects can get a TCO before the Confirmed rating is issued. The pro is flexibility. For example, I have had projects lately that had major delays getting their solar installed. I am not able to final a job until the PV is on the roof and functioning. But a house can obviously be occupied safely without solar. Cons are that if people get to move in before I finish my inspection and testing, I often have access problems and new liabilities as a jobsite converts into someone’s home.

Plan for what happens when a project does not meet it’s score requirement… An ERI score is a moving target, it will fluctuate throughout a construction project. Details and specs become available, changes and substitutions are made, inspection and test results become available, etc. I always try to build in a small point buffer to offset any score creep, but invariably some projects will land above their target. Some jurisdictions will say that the project needs to do what is necessary to gain the missing points. Sometimes that works. I have been able to ask builders to upgrade a hot water recirculation pump at final to make up a couple of points. But pretty quickly we run out of options for making points that don’t involve taking the house apart in some way, significant occupation delays, etc. This puts a lot of pressure on the Rater as this starts to get into real money fast. And a Rater does not have the authority or protections of an agent of a governmental jurisdiction. Raters aren’t enforcement officers. There needs to be a way out of this situation. Some jurisdictions use a fee-in-lieu of points model. I suppose that is a reasonable way to go, probably with some limitations.

Thirteen facts about Raters and ratings every jurisdiction should know…

1. Ratings are great for comparing the performance of simple, common, no-frills houses; production homes. The further from “average” the house is, the less reliable the rating is. I would not recommend using ratings alone to cap the energy consumption of custom luxury homes. Even if the software manages to compensate for the volume and glazing ration differences, once you start putting what are essentially commercial mechanical systems in a house, all bets are off.
2. Rating software is much more sophisticated than something like REScheck, but not sophisticated enough to really handle a complex mechanical system with complex controls and operation. Especially dual-fuel houses.
3. Rating software is not like mechanical system design software or Manual J & S software, like Wrightsoft or Elite. Rating software does not how to make “zones” comfortable, so I find it underestimates cooling loads in heavily glazed rooms.
4. Rating software simultaneously checks the energy model for compliance with 36 different codes and programs including; 2006 IECC Prescriptive to 2021 IECC ERI, ENERGY STAR, LEED, 45L Tax Credit, etc.
5. Ratings affect the construction schedule. As a job starts to wind down, there is often much pressure on a Rater to final inspect, test-out and produce a confirmed rating. Ratings cannot be finaled until the house is completely finished; solar installed, door hardware and thresholds installed, ventilators running, appliances etc. It takes at least two business days to get a final certificate from RESNET after a Rater makes the final inspection, builders often neglect to build this time into their schedule.
6. Ratings are not black and white. Different software and different Raters may get slightly different results. The more complex the house, the more ratings will vary.
7. Ratings don’t include all of the energy used in a project. Be cognizant of what is included in a rating and what is not. If you are trying to create a “total energy budget” for a house, know that ratings look only for specific items. People tend to ignore the little asterisks next to the HERS index utility bill estimate that says “*relative to an average U. S. home”. A model Renewables Energy Offset Program would need to catch, not just snow melted driveways and outdoor pools, but also everything about the house that is above “average” in order to have a comprehensive accounting of projected energy usage. And that “average” house is looking at a national scope, I find that almost all of the single-family houses I rate in Colorado are above average in the amount of energy that gets used beyond the scope of a rating. For instance rating do not capture… Anything outside the thermal boundary of the living spaces of the house, like; heated garages, ADUs, out buildings, pools, pool houses, fountains, patio kitchens, patio heating, snowmelt, hot tubs, etc. Items inside the house that a rating will not capture; make-up air for a large kitchen hood or draft inducer for a fireplace, steam showers, humidifiers, oxygen concentrators, elevators, radon fans, multiple redundant appliances, redundant heating systems, whirlpool tubs, pools, supplemental ventilation or dehumidification for pools, etc. We know from study by a local engineering firm (Resource Engineering Group, Crested Butte) that these items, that differentiate an average house from a custom luxury house, are the very things that make these houses exponentially more energy consumptive. Ignoring the burden of the luxury items is really a form of discrimination against anyone trying to build an average house.
8. Ratings are very harsh on uninspected existing assemblies and unstickered windows. If a project covers insulation before I get to inspect it, I am required to assume the worst, and grade the insulation at the worst possible installation level; poor installation. This can add several points to the final score, even though the insulation may have been great. It would help Raters immensely if jurisdictions would stamp the drawings with something like, “Confirmed rating required for CO. Contact the Rater of Record at start of construction, before insulation is installed, after insulation is installed and at substantial completion.”
9. Ratings don’t necessarily push projects to electrification. Ratings are based on dollars, not carbon. Ratings don’t know how clean or dirty the local electrical grid is. Science tells us that we should discourage the use of fossils fuels in new construction and embrace electrical technologies. If you want to incentivize electrification, then something more than a standard rating is required.
10. Ratings are typically full of assumptions and the Projected level. Raters usually get Design Development drawings without PV design, appliance schedule, glazing specs, etc. The rating will gradually get more accurate as the project develops.
11. Home Energy Raters are all certified by RESNET (Residential Energy Services Network) at least until another certification group emerges. Once certified, they can perform HERS, ERI ratings and issue IECC compliance documents. With a little more training and testing, they can issue ENERGY STAR documents. With a little more training and testing, they can become a Green Rater and issue LEED documents.
12. Rater certification and maintenance is not easy. Raters have to take classes in Building Science and how to use the software. Then pass the tests. Then you have to intern on a number of probationary ratings, all before you start work. It takes a load of expensive equipment to actually perform ratings- usually have about $25,000 worth of equipment in my car. I have to pay dues to a company to provide QA (Quality Assurance) which means they review my work answer questions and process the record keeping. Every year I pay for that company to send a representative to one of my jobs to do a live rating review on the spot. Every three years I have to complete 18 hours of continuing education. Plus annual equipment calibration, insurance, vehicle and computer overhead.
13. Raters have no power of enforcement on their own, other than the fear of a non-compliant score. No power to compel document changes, no power to reject work, no power to withhold a CO. If energy conservation measures are to be enforced on a project, then a Rater needs to be supported by the AHJ.

Below is my model code adoption language. Please use it, customize it and evolve it…

HERS model adoption language

1. The AHJ will stamp the rating type, goal and any other special requirements on the cover sheet of the record documents kept on site.
2. New construction projects, gut remodels and atmospherically detached Accessory Dwelling Units shall achieve a HERS score of 50 (Climate zone 7).
3. Addition projects shall have a Home Assessment made of the existing structure and recommendations undertaken. New work to follow Prescriptive requirements. Final infiltration test not required.
4. Multi-family units shall undergo compartmentation testing, whole-building tests will not be accepted.
5. Off-grid houses shall follow the Prescriptive path.
6. CO shall not be issued until confirmed rating is issued. A TCO may be issued for house that have completed testing but the confirmed rating is delayed for extenuating circumstances.
7. If a site is deemed unsuitable for PV; projects may calculate how much solar is required and install that amount off-site. Or PV may be purchased at a community solar farm. Or the PV may be donated to another building in the community.
8. Projects with non-compliant HERS scores shall; calculate how much additional PV it would take to make the score complaint and donate $7.00 per watt to a local community solar cooperative.

2021 IECC ERI model adoption language

1. The AHJ will stamp the rating type, goal and any other special requirements on the cover sheet of the record documents kept on site.
2. New construction projects and gut remodels shall achieve a 2021 ERI score of 60 without PV and a 2021 ERI score of 53 with PV (Climate zone 7).
3. Atmospherically detached Accessory Dwelling Units shall achieve a 2021 ERI score of 53 (Zone 7).
4. Addition projects shall have a Home Assessment made of the existing structure and recommendations undertaken. New work to follow Prescriptive requirements. Final infiltration test not required.
5. All ERI requirements of 2021 IECC Table 406.2 shall be met. The AHJ shall be responsible for all inspections in enforcement of the IECC.
6. Infiltration, ventilator efficacy and Total Duct Leakage test result reports shall be submitted.
7. Ventilator flow test result reports shall be submitted. Non-compliant ventilation flows shall be rectified and re-tested. In the event of the test not being able to be executed for technical reasons, ventilation flows may rely on manufacturer’s data plate specifications.
8. Multi-family units shall undergo compartmentation infiltration testing, whole-building tests will not be accepted.
9. Off-grid houses shall follow the Prescriptive path.
10. CO shall not be issued until confirmed rating is issued. A TCO may be issued for house that have completed testing but the confirmed rating is delayed for extenuating circumstances.
11. If a site is deemed unsuitable for PV; projects may calculate how much solar is required and install that amount off-site. Or PV may be purchased at a community solar farm. Or the PV may be donated to another building in the community.
12. Projects with non-compliant ERI scores shall calculate how much additional PV it would take to make the score complaint and donate $7.00 per watt to a local community solar cooperative.

Please note that I work in the mountains, custom luxury home market- climate zones 6 and 7. This could all change quite a bit in another part of the country. I don’t know a thing about termites, exterior vapor retarders, radiant barrier, etc.…

Thank you,

Mark McLain

Architect

ICC/HERS Compliance Specialist

ICC Residential Energy Inspector/Plans Examiner

RESNET Certified Home Energy Rater

BPI Building Analyst Professional

BPI Multi-family Building Analyst Professional

Link to Colorado Energy Conservation Code Hub for; Aspen, Basalt, Carbondale, Eagle County, Pitkin County, Town of Snowmass Village and the Town of Mountain Village