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More Building Science
Smart people in the home-building industry have a saying about codes: A code-built house is the worst house allowed by law. The implication behind that statement is that if all you’re doing is meeting the code, you’re probably short-changing the people who will live in the house. The folks at the International Code Council (ICC) are doing their best to make sure that that barely-legal house is worth living in.
Code-minimum closes in on high-performance
If I told you that your new home had to meet the following requirements, would you call that a high-performance home?
- Be pretty darn airtight (3 ACH50 for all but the two warmest climates, zones 1 and 2, and 5 ACH50 for them) and be verified with a Blower Door test
- Have almost no total duct leakage (4 cfm25 per 100 square feet, the same as ENERGY STAR Version 3 for leakage outside the building envelope), as verified by a duct leakage test
- Include a mechanical ventilation system if the airtightness is less than 5 ACH50 (which catches all new homes except those that come in at exactly 5 ACH50 in climate zones 1 and 2)
- Increase attic insulation from R-30 to R-38 (climate zones 2 and 3) or R-38 to R49 (climate zones 4 and 5)
- Increase above-grade wall insulation from R-13 to R-20 (climate zones 3 and 4)
- Insulate above-grade walls to R-20 in the cavities plus R-5 continuous (e.g., 1″ XPS foamboard sheathing) or R-13 cavity plus R-10 continuous in the cold climates of zones 6, 7, and 8
- Install really good, double-pane, low-e windows.
I’d surely call a home built like that a high-performance home. Those specifications are part of the 2012 International Energy Conservation Code (IECC), which you can read more about in Martin Holladay’s 2012 IECC overview. The 2009 IECC was a big step up from 2006, too. When we adopted IECC 2009 here in Georgia, we instituted mandatory airtightness and duct leakage testing, so we’re a step ahead on that requirement.
What about Energy Star?
So, if the energy codes are getting so much better, what will happen with energy efficiency programs like Energy Star new homes? Since the mid-1990s, more than a million new homes have qualified for the Energy Star label. The reason the numbers are so high is that the program set its requirements to an attainable 15% better than the energy code. As the codes get more stringent, Energy Star gets more stringent, and home builders have begun to reassess their priorities.
Is it possible that for the many builders who have participated in Energy Star and had their homes labeled with the well-known brand, satisfying the energy code will become sufficient? Will only the extreme programs, like Passive House, survive?
I answer that question with an emphatic NO. It boils down to two words: adoption and enforcement. The IECC is a model code, meaning that it’s just a suggestion from the ICC. If no one adopts it, it’s meaningless. For those jurisdictions that do adopt it, the code is only as good as its enforcement.
Even if the requirements were exactly the same, I’d take an Energy Star Version 3 home over an IECC 2012 home. My reason? The Home Energy Raters who qualify Energy Star homes, on average, have more training, knowledge, and skill in the process of verifying compliance with energy efficiency requirements and in finding building science problems than those who do building inspections for code. Building inspectors generally do a lot more inspections in a day, and are responsible for looking at a lot more than just the energy efficiency details, so it’s not really a fair comparison. In addition to their greater knowledge and skill in building science, HERS raters also are subject to quality assurance rules that have someone looking over their shoulder and checking their work.
That’s where we are right now anyway. The ICC is pushing hard, and states are getting their acts together (well, some are). I hope that eventually the people who verify energy codes will have to meet similarly stringent training and quality assurance requirements as HERS raters. If and when we get to that point, my answer to this big question may change.
What do you think?
Allison Bailes of Decatur, Georgia, is a RESNET-accredited energy consultant, trainer, and the author of the Energy Vanguard blog.
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18 Comments
There is room for all...
10 or 12 years a go, 100 or so folks from the “green” building community around the country, we got together in Portland, OR, to talk about the development of a ‘National Standard’ for green building guidelines for the whole country; and at that meeting we hoped that in 20-30 years, that set of guidelines would become code and ‘green building’ disappear and become normal and good building practices. That ‘National Standard” became the LEED for Homes program, then the NAHB Guidelines was developed shortly behind, then ES started to upgrade their program to compete with those two programs, and finally ICC started to catch-up with everyone else to the point of pushing the codes to what we called green guidelines in the 2000’s. But as you said, Allison, it all depends on adoption, implementation and verification.
I still believe there is room for all green building programs to stay ahead of the codes, and to many folks, to help develop new techniques, methods and products for those who want to differentiate their building business from their competition.
Have to agree
I have to agree with you on this. I just inspected a home built in 2002 where all the flat attic areas were not insulated. Yet the builder & building inspector signed off that the home was complete. I would much rather have a 3rd party inspecting my home for energy related issue as that is what is going to drive my operating costs.
With Regards to Energy Star
Energy Star for years was the first step in High Performance Homes. Now with over 1 million certified its success as a government program (a rare event indeed) cannot be denied. However the goal to stay 15% better than code invokes the law of diminishing returns. As a rater for over 10 years I have seen the improvements in home construction. The details once glossed over are now the focus of attention. I think it may be time to put the program out to pasture. NAHB remember is the only ANSI standard at this time for green certifications. At the lower end of the scale is RESNET's HERS certification which builders are using as the next "Green" marketing step replacing Energy Star as the costs cannot be justified in the current economy. Finally there are too many programs in the market today causing confusion to both builder and home buyer. In my opinion less is more.
2012 IECC
As a long time code official, I'm optimistic that building code professionals and adopting jurisdictions will step up to the challenge of implementation and training to earn the confidence of the public. As a technical matter, the energy conservation reqs in the IECC are simple building science, not rocket science. Building inspectors already do far more complex technical inspections in other areas. As a practical matter, jurisdictions will have to step up to shoulder this responsibilty, since there will be many projects that will not be based on participation in a third party program. ICC and its members and partners are investing an unprecedented amount of resources in support of this code, and building code officials are accepting these new responsibilities quickly. The 2012 IECC aligns very closely with EStarv3, and having both alternatives available gives the customer flexibility.
Efficiency Programs Struggle to Stay Ahead of Energy Codes
Allison makes a very good point. Here in California, state energy policy is driving all new construction to net zero with all new homes suppose to be net zero by 2020 ( a short 8 years away). The CPUC and CEC are hoping to achieve this goal through Title-24, and the latest update to 2013 T-24 standards shows a 25% improvement over the strigent 2008 code. As a utility researcher who advises our new construciton program, it's becoming increasingly difficult to justify a utility sponsored new construction program with each up tick in the title-24 code. But maybe that's the point.... If a code built home is the "worst built home allowed by law" and the technical means exists to build net zero homes (and buildings), why shouldn't the code express this? Granted it might put me out of a job, although there's millions of poorly performing existing homes and buildings that need attetion, but I've always been struck by the fact that the building profession has always expected second (third, fourth, or worst) best. It's truely amazing how little innovation takes place in the building business. A major goal of our utility program, SolarSmart Homes, is to "transform the market," meaning that at some point we stop providing utility ratepayer incentives to programs like Energy Star because the market has changed. New construction also implies new, or best, so why shouldn't new homes and buildings be the best they can be? The harder, more urgent and more important task is how do we upgrade the performance of the existing building stock. It seems we'll need to leverage changes in the code to help us achieve that goal, too.
Where's the incentive
Without the carrot (or stick) of ARRA-type federal money it is unlikely we will see states adopt 2012 IECC like we did with the 2009 IECC. NM, a relatively progressive green state, is not even considering it. Meanwhile, Energy Star over reached with 3.0 (given current market conditions) and production builders are abandoning it in droves. For better or worse, RESNET and it's HERS rating is winning the game and the market is responding to it as it becomes the default national standard. The good news is that its IS a third party private process that takes busy code inspectors out of the process. The bad news is that it has no mandatory provision for healthy air exchanges as the homes get tighter and tighter. Should we not give in to the HERS juggernaut and help them develop air quality standards? Why not?
The moving target for conscientious Energy Professional
Sad to think that I have seven years into creating an auditing business that may essentially evaporate in it's current state, but so goes the efficiency business. I am already seeing builders unable to meet ENERGY STAR because they aren't willing to address the costs of the new requirements with their HVAC contractors who are unwilling to complete the paperwork without getting paid for it.
I have been preaching to my builders to have a meeting of the minds with their trades to discuss these matters with little success. My only protection to get paid for inspections is to be very up front with re-inspection fees and give the builders the tools to contract with the responsible trades to try and avoid them. Of course, identifying all the costs could very well be self defeating for me if it causes them to opt out of the program.
My other comment is that code homes in our area are not up to the energy code as most inspectors have refused to focus on anything having to do with correct alignment of insulation and correct air sealing of new homes.
Overall it has truly been a love/hate relationship with the whole efficiency industry. I am probably going to have to refocus on existing homes to survive (which isn't a bad thing) if this all plays out the direction it's heading.
Air Quality Standards
Kim - We don't need RESNET to develop an air quality standard - we have a recognized one already - it's called ASHRAE 62.2
Response to Amanda Evans
Amanda,
Not to quibble -- but ASHRAE 62.2 is a residential ventilation standard, not an air quality standard. There is a difference.
HERS Rating does not equal energy performance
A brief analogy. If I step on the scale it doesn’t mean I’m healthy. The scale might say I weigh 250lbs, not a very healthy weight for me. My sub-three-hour marathons only seem possible below 185lbs, (Although, 183lbs doesn’t mean I’m healthy either—weight is only a single indicator, best not used in isolation.) The scale is a useful tool. But it’s particularly useful not because weighing myself means I’m healthy. So why state this perhaps obvious fact?
A couple of the comments here seem to imply that a HERS rating establishes that a home has cleared a performance threshold. It does not. The worst performing home in the world can have a HERS rating, albeit a very high (poor) score. A HERS rating is a measurement tool, a scale, not certification that the house performs well. HERS is not a replacement for ESv3 (or LEED or an ANSI Green Building Standard—an there is a post in itself “ANSI” doesn’t mean “right”. ANSI doesn’t vet the content, but rather the process, a process which can yield a bad standard.) This may be a bit tangential to the original post, but it’s worth keeping in mind for the discussion.
Cheers,
Mike
Air Quality Standard
I know Martin - I was responding quickly to Kim's language and didn't word my response correctly. Thanks.
R-5 (1") Cont in Zone 5?
I thought the recommended minimum foam thickness in Zone 5 is 1.5"?
Great comments!
Thanks for all the great comments! (But please don't take this as a sign to stop.) Mike Rogers beat me to it here, but one that struck me in a couple of the comments above is that there's confusion about what a home energy rating actually is. It's just an evaluation tool, even if RESNET is out there pushing builders to market the HERS Index. See the article I wrote about this in our blog today: A Home Energy Rating Is Not an Award.
Code improved because of Energy Star
As an ICC member, an energy code trainer for the past ten years, and a former energy rater I have seen the energy code follow in the footsteps of the Energy Star new homes program. In most cases the Energy Star program has transformed the residential construction market (Denver, Las Vegas and Phoenix in the southwest where I work) so that standard code built homes on a HERS scale are scoring below an 80. It was this transformation that took place in the residential market that allowed the code to move so far so fast because code officials and industry were building efficient homes. As I work with building departments across the southwest I typically find the approach these building departments will take are a combination of department field inspectors and energy raters. With the Rater or BPI analyst performing the majority (99%) of these new code requirements such as mandatory air filtration testing and duct testing depending upon the location of the ducts. One of your other commenter's correctly said that ICC and U.S. DOE through the Building Energy Codes Program (BECP) are working feverishly to provide education and tools for building departments to enforce the energy code. There is still room for advancement beyond the 2012 IECC through Energy Star v3, the DOE Challenge Home, and the drive for net zero energy.
Pushing the Envelope to Absurdity
There is no argument that a home should be built to code with regard to structure and design but everything gets blurred and costly when one starts down the path of mandating certain energy criteria. The changes identified in this article require numerous 3rd party consultants / service providers each looking to make money off of mandated rules. If this processs was required for cell phones or computers we would still be using 1980's technology. Can you imagine Steve Jobs waiting for a "chip efficiency" rater to show up and determine that the iPhone's chip use was in line with code?
All of these rules totally impeade creative thinking with regad to home design and construction because each step of the way raters, inspectors and even suppliers don't know how to handle something different. We just built two kit homes from AmeriSus that eneded up with outstanding levels of energy performace with absolutley no certifiaction, no blower door test, no duct tect, etc. The company is so darn sure they produce the most affordable eco-home that the provided a guarantee on energy use and if the usage goes over an established level (about $50 / month at today's rates) they will pay the difference.
Duct Testing Correction
The article implies that the 2012 IECC duct testing requirement is the same as E-Star v.3. Actually, the 2012 IECC exceeds it??, though I don't agree with their method. E-Star requires
The rough-in test is somewhat ridiculous since it will not measure leakage around duct boots through drywall that is not installed at this stage. I think the E-Star test makes more sense. Interior leakage should not be held to the same standard as exterior leakage.
Riley/AmeriSus Unique in the Real World
Riley- Your experience with AmeriSus tells me more about the merits of building with a kit home than why we don't need inspections to build homes that are more efficient. A brief read on AmeriSus describes a company that has applied R&D to a process and product mix that is outside the range of most builders. "Pre-engineered" means that the costs associated with verifying the product mix and processes were invested up front and, in this case, spread out over every home they ship instead of just one or a few homes.
Production builders that I work with can achieve the same efficiencies because they are spreading the learning curve over many homes each year. But even their homes have systems that need to be checked and verification for quality installation on certain materials that are critical to performance. A few common examples are checking the air flow over the coils on a heat pump, advanced air sealing and insulation installation, and ventilation fans that pull anything close to their rated CFM. In the real world, everyone just assumes that these things work when they are installed but testing confirms that this in not the case.
Being involved with efficiency since 2005, I can tell you that the only reason our now well trained trade base even knows how to perform the processes that result in efficient homes is because of the tremendous investment by the programs by way of training and subsidized market transformation. Maybe the day is coming when programs and third parties might not be needed but someone needs to know what is important and how to check to be sure that things are done right.
I'm pretty sure I wouldn't go back to an auto mechanic who put new spark plugs and wires on my car and never checked to see if it ran right, even though he was pretty darn sure it did.
NAHB Research Center vs RESNET
At the recent NAHB Spring Board Meeting, the NAHB Research Center made a presentation to one of the subcommittees of the Construction Codes and Standards Committee on a cost benefit analysis of the 2009 IECC versus the 2006 IECC. Their conclusion was that it pays for itself within seven years and was therefore reasonable. Then they compared 2012 IECC versus 2009 and deemed the payback to be something like 20 years and therefore unacceptable. The point of the research was to provide ammo for those who may be trying to convince local and state code adopters that the 2012 IECC was a code too far.
The problem with the NAHBRC model, was its "grossness". In an attempt at simplicity, they based their conclusions on an average house, in an average climate zone, in an average moisture zone, with average construction costs, average occupant loads, average utility costs, and on a prescriptive basis only.
So when somone tries to use it as "proof" in any given locality, local administrators will be able to legitimately counter that the data does not represent local conditions, (unless they are truly "average"). And even then a builder could probably follow a creative performance path, get a HERS rating equivalent to the prescriptive path assumption, and bust the NAHBRC construction cost numbers.
I offered the suggestion (as the Executive Officer Liaison to the committee) that perhaps RESNET should be solicited as a research partner. Having recently completed their millionth HERS rating, they should have the potential to glean and provide an immense amount of data for every climate zone, every size home and with every imagineable utility cost. Competent raters can also calculate the presumed energy cost in dollars, BtUs, therms, etc.
RESNET cannot provide the cost of construction or energy efficiency upgrades, nor can they accurately predict occupant behavior, but they certainly could provide more accurancy and relevant data than the woefully inadequate conclusions reached by the NAHBRC.
RESNET has its place as the dominant national measurement tool. Hopefully they will recognize their potential role as a national data collection service and begin to help influence local and national policy directives.
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