States are Amending, then Adopting, the 2015 IECC

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States are Amending, then Adopting, the 2015 IECC

As usual, the code adoption process in the U.S. is a mixed-up mess

Posted on Oct 28 2016 by Martin Holladay

In the U.S., the system for writing, adopting, and enforcing building codes is peculiar. Lots of people are confused about building codes.

Anyone interested in understanding building codes in the U.S. needs to start by learning a few basic facts:

  • The U.S. doesn’t have a national building code. Building codes vary from state to state, and in some cases from city to city.
  • In some areas of the U.S., municipal officials tell builders that there are no building codes whatsoever for builders of single-family homes. Be careful, though: in many cases, codes apply — they simply aren't enforced.
  • The best-known code-writing organization in the U.S. is the International Code Council (ICC) of Falls Church, Virginia. The ICC is a non-profit organization; the group is not an arm of any government. The ICC writes “model codes” that have no force of law — unless, that is, a state, county, or municipality decides to adopt one of the model codes.
  • When a state or other jurisdiction adopts a model code, it rarely adopts the code as written. Instead, it usually adopts an “amended” (altered or edited) version of a model code.
  • Because of the facts listed above, builders who work in more than one jurisdiction must learn how to work under different versions of the building code.
  • Even when a code is adopted by a state or municipality, code provisions often remain unenforced.

The ICC codes that are most relevant to residential builders are the International Residential Code (IRCInternational Residential Code. The one- and two-family dwelling model building code copyrighted by the International Code Council. The IRC is meant to be a stand-alone code compatible with the three national building codes—the Building Officials and Code Administrators (BOCA) National code, the Southern Building Code Congress International (SBCCI) code and the International Conference of Building Officials (ICBO) code.) and the International Energy Conservation Code (IECC). These codes are written in three-year cycles, which means that every three years, a new version of the code is published. That’s why builders and code officials refer to the 2009 IRC, the 2012 IRC, or the 2015 IRC.

When states adopt a building code, they can adopt any version they want, and they are under no obligation to update the code when a new version of a model code is published. (There are a few exceptions to this rule: in some states, legislation has been passed to require automatic adoption of updated codes.) State-to-state variations are common; for example, Wisconsin is using the 2009 code while Iowa is using the 2012 code and Illinois is using the 2015 code — all at the same time.

In recent months, some states have begun to adopt versions of the latest edition of the IECC, namely the 2015 IECC. States that have done so include llinois, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New York, Rhode Island, Utah, and Vermont.

A HERS Index can be a path to compliance has published several articles on the 2015 IECC, including the following:

As these articles explain, one of the new compliance paths available to builders under the 2015 IECC involves getting a HERS Index for a new home. (The code refers to this rating as the Energy Rating Index, or ERI; but for all intents and purposes, an ERI is the same as a HERS Index. For more information on the HERS Index, see How Is a Home’s HERS Index Calculated?)

Builders who need to comply with the 2015 IECC get to choose between several compliance paths. One is the prescriptive path — a path that (basically) requires the builder to meet minimum R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. specifications for floor, wall, and roof insulation, as well as maximum U-factorMeasure of the heat conducted through a given product or material—the number of British thermal units (Btus) of heat that move through a square foot of the material in one hour for every 1 degree Fahrenheit difference in temperature across the material (Btu/ft2°F hr). U-factor is the inverse of R-value. specifications for windows.

Another is the Total UA Alternative path; for more information on this compliance path, see Are Energy Codes Working?

Still another path is the performance path (technically known as the "simulated performance alternative") — a path that requires the builder to use energy modeling software to show that the proposed house won’t have energy bills that are any higher than a house of the same size complying with the prescriptive path.

A brand new compliance path in the 2015 IECC is the ERI path. This voluntary path removes some prescriptive requirements for builders who get the home rated (in most cases, this means getting a HERS Index rating) and who meet the maximum target score listed in the code.

The 2015 IECC lists the HERS (or ERI) target scores for each climate zone, as follows:

  • 52 for Climate Zones 1 and 2
  • 51 for Climate Zone 3
  • 54 for Climate Zone 4
  • 55 for Climate Zone 5
  • 54 for Climate Zone 6
  • 53 for Climate Zones 7 and 8

Under the HERS (and ERI) scoring system, low numbers are good; high numbers are bad. To hit the required target, a builder needs a score equal to or lower than the target number.

According to the 2015 IECC, if the builder of a subdivision with many identical houses wants to use the ERI path, then every single house in the subdivision must be tested, inspected, and rated. In all cases, for production builders as well as small builders, ERI ratings must be performed by a third party — not by the builder. According to RESNET, a national association of home energy raters, “The third party serves as an energy consultant to the builder and can reassure the code official that an energy-efficient, code-compliant home is built.”

There’s one more wrinkle to the new code: A builder who chooses the ERI path for compliance under the 2015 code still has to meet the prescriptive requirements for the home’s thermal envelope (wall R-value, ceiling R-value, etc.) specified by the 2009 IECC. While these prescriptive requirements are somewhat less stringent than the prescriptive requirements in the 2015 IECC, they still represent a significant list of specifications that need to be met. When a house meets the ERI target listed in the 2015 IECC as well as the 2009 prescriptive envelope requirements, the house is deemed to be in compliance with the 2015 code.

If the 2009 prescriptive envelope requirements aren’t followed, then the house isn’t in compliance — even if it has an ERI score below the target.

Lights and appliances count

In most cases, building energy codes regulate the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials.. In some cases, building energy codes may regulate the efficiency of a home’s heating and cooling equipment. But codes generally don’t regulate appliances like washing machines or refrigerators. That will change, however, for builders who choose to follow the ERI path in the 2015 IECC. Anything that can affect a home’s HERS Index — including lighting, appliances, and drainwater heat recovery devices — now counts toward the code compliance goal.

The contribution of a roof-mounted PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. array is also counted when determining a home’s HERS Index. Whether a PV array can be used to meet an ERI target for compliance with the 2015 IECC, however, has become a contentious issue.

Before delving into the question of whether a PV system can be used to lower a home’s ERI, it’s worth looking at the way states are amending the 2015 IECC.

States are amending the 2015 code in favor of less stringent ERI targets

While model code developers dream of a nation — nay, a world — with code consistency, state legislators have different ideas. “Builders have been lobbying for ERI targets not to be too stringent,” said Steve Baden, executive director of the Residential Energy Services Network, or RESNET. (RESNET is a national association of home energy raters.) “There’s a debate about appropriate ERI scores. Different states are adopting different numbers.”

In other words, the code is being amended as it is being adopted. In all cases, these amendments have made the adopted code less stringent, not more stringent.

At the recent EEBA conference in Texas, Shawna Cuan, an energy efficiency program specialist for the Utah governor’s Office of Energy Development, told conference attendees that Utah adopted a “modified version” of the 2015 IECC residential code. For Climate Zone 6, the ERI target was changed from 54 to 68; for Zone 5, it was changed from 55 to 69.

At the same conference, Clayton Traylor, a staff member at an organization called Leading Builders of America, described how the 2015 IECC was amended in the Lone Star state. “As adopted in Texas, the target score is 65,” said Traylor. Needless to say, an ERI score of 65 is higher (less stringent) than the IECC target for any climate zone in the country.

In Illinois, unlike in Utah or Texas, the ERI targets weren’t amended when the 2015 IECC was adopted. But even in Illinois, legislators couldn’t resist lowering the bar for other provisions. According to Matt Gingrich, the executive director of Energy Diagnostics, an energy rating firm based in northwest Indiana, “The ERI targets were not amended in Illinois, but the airtightness target was raised from 3 ach50 to 5 ach50.”

Using PV to hit the ERI target

In states where the 2015 IECC has been adopted, some building officials are unhappy with the fact that builders can use roof-mounted PV systems to lower an ERI score. In Florida (where state legislators, idiosyncratically, tacked on the ERI path to the Florida version of the 2012 IECC that was recently adopted there) raters are allowed to consider the contribution of a PV system when calculating an ERI score. On the other hand, Texas has enacted a regulation stipulating that PV contributions can’t be counted when calculating an ERI.

According to Steve Baden, the 2015 code allows for PV credits. “Energy contributed by an on-site power system can be credited to an Energy Rating Index score according to the ANSIAmerican National Standards Institute. National nonprofit membership organization that coordinates development of national consensus standards. Accreditation by ANSI signifies that the procedures used meet the Institute’s essential requirements for openness, balance, consensus, and due process. / RESNET / International Code Council Standard 301,” Baden wrote to me in an email. “There are, however, a number of proposals to be considered at the 2018 IECC hearing to either prohibit or restrict such contributions. We will see what comes out of Kansas City.”

It's hard to know how many builders will use the ERI path

In states where the 2015 IECC has been adopted, it's not yet clear how many builders will adopt the ERI path. Most builders will undoubtedly choose the path that seems easiest. For builders who don't want to work with a third-party energy consultant, the prescriptive path will probably be easiest.

Builders who are willing to hire an energy consultant may find that the performance path is preferable to the ERI path — in part because the performance path is more flexible, inasmuch as it doesn't require builders to comply with the 2009 IECC prescriptive envelope requirements the way the ERI path does.

In a phone conversation about the ERI path, Robin Vieira, the director of buildings research at the Florida Solar Energy Center, explained why some states are amending the ERI target numbers before adopting the 2015 IECC. “When you look at the ERI target numbers that were put into the 2015 IECC, you see that they are more stringent than needed for a house built to the performance code,” Vieira said. “So the ERI path is not likely to ever be used.”

Whatever happens, demand for blower door tests is going to increase

Since the average builder doesn’t spend much time keeping up with the code development process, many builders are surprised when newly adopted codes require them to learn new skills.

For builders who are working in areas that are still governed by the 2009 codes, the biggest looming change — one that will hit them when their state adopts the 2012 or 2015 version of the IECC — is the new code focus on airtightness. Both the 2012 and 2015 versions of the IECC require homes to pass a blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas.. Unless states amend these codes, the air leakage target for Climate Zones 1 and 2 is 5 ach50, while the target in Zones 3 through 8 is 3 ach50.

At the EEBA conference in Texas, Liang Gwee, an associate product manager at Owens Corning, told attendees, “On September 1, Texas required new homes to achieve 3 ach50. That has caused some anxiety for builders.”

Any entrepreneurs looking for a business opportunity might consider the fact that adoption of the 2012 and 2015 codes will lead to big increases in the need for blower door testing.

Martin Holladay’s previous blog: “Ventilation Failures and Vocabulary Lessons.”

Click here to follow Martin Holladay on Twitter.

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  1. Randy Martin

Oct 30, 2016 1:02 PM ET

From the middle of the mess.
by Andy Kosick

I comment mostly out of frustration. Having been doing testing and performance improvements in existing homes for a few years now, this past year has thrust me into codes and new homes like never before, largely because of the new code (Michigan). I'm not the only blower door in the area but it feels like it.

The first problem is that everyone got the air tightness memo but not the the ventilation memo, this includes many inspectors. Since I see this as two sides of the same coin it has put me in a difficult position. Even though the code requires ventilation it doesn't specifically require it to be tested (I know I'm the only one around here doing that), it seems both building and mechanical inspectors are having difficulty understanding what continuous mechanical ventilation is. In example, I just tested a house at 1.8 ACH50 and it had a 4" flex from outside to the return air duct flowing under 10 CFM and besides that the homeowner was planning to heat the place with his pellet burner so the furnace wouldn't even be running anyway. In a case like this I just make sure to inform the builder/homeowner about the need for ventilation in tight houses.

Second is the strange grey area created by this testing. Although we testers are contracted by the builder it's clear the builder and inspectors often see us as some kind of pseudo inspector. The inspectors are happy for you to take on some of their responsibility and the builders want you to advocate for them. Another Rater just told me that the local code authority said he was on the books as a "special inspector" and was obligated to tell them about any other code violations he saw, which is definitely not a good policy. The other extension of this grey area is that we are largely being called in at the end of a project to test for a condition that can no longer be easily fixed, when it fails the blower door test everyone involved just looks at me, and of course they should have been looking at me a couple months ago, but construction schedules seem very difficult to change. Thank goodness hitting 4 ACH50 isn't actually the problem it's more about measuring how tight the house is and ensuring an appropriate ventilation system is in place, which leads us back to my first issue.

I'm not sure this code is really improving homes in my area yet but it has started an important conversation that will continue. I see my failings right now as a lack of out reach to inspectors and builders to address these things up front. A problem I hope to address soon. Despite the issues I am happy to be doing this, I guess I'm just wondering how others are dealing with the code required blower doors.

Oct 30, 2016 3:55 PM ET

In Canada
by Malcolm Taylor

There is a common misapprehension that because some rural or remote areas don't require building permits or provide inspections, that the codes don't apply. Codes here are enacted for the entire provinces and it is the responsibility of the owner doing or contracting the work to make sure they meet the codes.

Oct 30, 2016 8:45 PM ET

Five paths to compliance?
by Douglas Horgan

In addition to the three you've listed, one might say are two other listed means of compliance in the model code.
The first is the "Total UA Alternative" (R402.1.5), where one can trade off a better-than-code area of the building shell for an area that doesn't meet the prescriptive code minimum. ResCheck software is almost always used for this method. I see a number of renovation projects where shallow roof assemblies that can't hit the R-49 requirement are traded off with better windows.
The second is a "low energy building" with a peak design rate of energy usage less than 3.4 Btu/h * ft^2, section R402.1.
The second doesn't seem to play much of a role in real code use, but the first is used all the time. It's just a variation on the prescriptive requirements but we often find people who don't realize that a small area that can't quite hit the prescriptive requirement can be managed with a calculation rather than with closed cell spray foam.

Oct 31, 2016 7:22 AM ET

Response to Andy Kosick (Comment #1)
by Martin Holladay

Thanks for the report from the front lines. Over the past 30 years, the type of builders who latch onto the idea of airtight construction have tended to be the kind of builders who like to study these issues and learn about building science and "house-as-a-system" concepts.

Now a much larger group of builders -- those who merely try to barely comply with the building code -- are learning about airtightness. It's going to be an interesting (and bumpy) transition.

Oct 31, 2016 7:42 AM ET

Edited Nov 5, 2016 11:46 AM ET.

Response to Malcolm Taylor (Comment #2)
by Martin Holladay

As far as I know, you're right, in the U.S. as well as in Canada. But this situation is relatively new. During Obama's first term, legislation was passed that provided federal stimulus money to the various states, but the grants were contingent on the states adopting state-wide building codes. As far as I know, that happened in every state -- even in places like Maine that never had residential codes in rural areas.

Those of us who live in rural areas still don't have building permits or inspections -- it's an "honor system" approach. I tell builders (when they ask) that they are legally obligated to obey building codes, even when these codes aren't enforced. This issue almost never comes up -- unless there is litigation, in which case failure to comply with building codes suddenly matters.

Oct 31, 2016 7:51 AM ET

Edited Oct 31, 2016 7:56 AM ET.

Response to Douglas Horgan (Comment #3)
by Martin Holladay

Thank you for your correction. The number of code compliance paths varies from state to state, but in general, there are usually either 4 or 5 compliance paths, not three, as you correctly point out.

In one of my previous code articles (Are Energy Codes Working?), I included a full description of the Total UA Alternative path.

Oct 31, 2016 3:34 PM ET

by stephen sheehy

Municipalities with fewer than 4000 people are still permitted to have no building code. My town, Whitefield, is one. No code, no permits, no inspections, other than drains and vents.
If we adopted the state code, it would be the 2009 IBC and IEC. Not having a code is nuts, in my opinion, even though convenient for builders.

Oct 31, 2016 4:04 PM ET

Response to Stephen Sheehy
by Martin Holladay

You may be wrong. I think the code applies, but municipalities with fewer than 4,000 people aren't required to enforce it.

So it's like a stretch of highway with a posted speed limit of 50 mph, but no cops. The law applies, but it isn't enforced.

For more information, see this document.

"All building construction in Maine, with some exceptions, is governed by the Maine Uniform Building and Energy Code (“MUBEC”)...

"1. On December 1, 2010, this Code shall be applicable statewide.

2. No later than December 1, 2010, this Code must be enforced in a municipality with a population of 2,000 residents or more that had previously adopted any building code on or before August 1, 2008.

3. No later than July 1, 2012, this Code must be enforced in a municipality with a population of 2,000 residents or more that had not adopted any building code on or before August 1, 2008.

4. All provisions of the MUBEC are applicable in a municipality with a population of less than 2,000 residents, but municipal enforcement of the MUBEC is voluntary."

Oct 31, 2016 8:53 PM ET

Reply to Martin
by stephen sheehy

As far as I can determine, the "2000 residents" was changed to "4000 residents" and towns with fewer than 4000 have the option to "not adopt any code" as well as to simply not enforce the code. As a practical matter, it doesn't matter.

Oct 31, 2016 9:00 PM ET

by Malcolm Taylor

Apart from liability, are there any other direct consequences of not having codes? Insurance? Access to mortgages?

Nov 1, 2016 4:26 AM ET

Response to Stephen Sheehy (Comment #9)
by Martin Holladay

Town with fewer than 4,000 residents don't have to adopt a code, because "All building construction in Maine, with some exceptions, is governed by the Maine Uniform Building and Energy Code" and because "On December 1, 2010, this Code shall be applicable statewide" and because "All provisions of the MUBEC are applicable in a municipality with a population of less than 2,000 [now 4,000] residents."

Adopting a code on the local level is unnecessary, because Maine has a state-wide code.

Nov 1, 2016 4:28 AM ET

Response to Malcolm Taylor (Comment #10)
by Martin Holladay

I live in a rural area without any building permits or inspections. Like Stephen Sheehy, I live somewhere where most builders assume "we don't have any codes here." (We actually do, but municipal officials aren't aware of it.)

Those of us who live here have access to mortgages and insurance.

Nov 1, 2016 11:11 AM ET

reply to Martin comment11
by stephen sheehy

Martin- here's where I got the notion that there's no code in my town, rather than it's just not enforced:

"Municipalities with less than 4,000 residents are not required to enforce MUBEC, MUEC or MUBC unless they wish to do so and have the following Options:

1. Chose to adopt and enforce the MUBEC as listed above

2. Choose to adopt and enforce MUBC (the building code without energy code in it)

3. Choose to adopt and enforce MUEC (the energy code only)

4. Choose to have no code"

I'm not exactly clear what that means, but it sounds like a town can affirmatively decide not to have a code. Probably not relevant unless there is some litigation over a project where alleged failure to comply with code is possible evidence of lack of reasonable care on the part of a builder.

Of course as a practical matter, it means that some portion (maybe all?) of the houses being built don't comply with the 2009 IBC or IECC. The lack of any electrical inspections is particularly troubling.

Nov 1, 2016 11:35 AM ET

Response to Stephen Sheehy
by Martin Holladay

Thanks for the further information. I wonder how many towns have affirmatively indicated their decision to "have no code."

The situation is rather murky -- but your information is helpful.

Nov 2, 2016 6:17 PM ET

by kim shanahan

Martin, you said: "Builders who are willing to hire an energy consultant may find that the performance path is preferable to the ERI path — in part because the performance path is more flexible, inasmuch as it doesn't require builders to comply with the 2009 IECC prescriptive envelope requirements the way the ERI path does."

But earlier you said that following the ERI WAS a performance path (which it is). I think you meant to say that doing a whole house UA would alleviate the need to comply with the 2009 IECC prescriptive path. At least that is how I have understood the options.

Interestingly, code negotiations for the 2018 IECC, that recently took place in Kansas City, apparently raise the ERI numbers, meaning less stringency, but also peg the prescriptive baseline to the 2015 IECC rather than the 2009 IECC. That's a big shift in the baseline.

Nov 2, 2016 7:18 PM ET

Response to Kim Shanahan
by Martin Holladay

You are right that some people might call the new ERI compliance path a "performance" path. But it's not the only performance path available to builders under the 2015 IECC.

When I referred to the "performance path" in this article, I was talking about the "simulated performance alternative" that has been in the IECC for several years. It can be found in Section R405. The code states, "Compliance based on simulated energy performance requires that a proposed residence ... be shown to have an annual energy cost less than or equal to the annual energy cost of the standard reference design."

This "simulated performance alternative" can still be found in the 2015 IECC, in addition to the new ERI compliance path.

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