Power Attic Ventilators Banned by New Georgia Energy Code
A couple of months ago, I wrote about why you don’t want power attic ventilators in your home. Whenever I’ve written about this topic, it just seems to set some people off. I get comments like, “You really should do more research before you post blogs like this,” and, “You don’t know what you are talking about!” My favorite, I think, was, “You need to go get some more degrees!” (Sorry. Ain’t gonna happen. I’ve got plenty of learning left to do, but I’m done getting ‘lettered,’ as another commenter in our blog put it.)
A couple of months ago, I wrote about why you don’t want power attic ventilators in your home. Whenever I’ve written about this topic, it just seems to set some people off. I get comments like, “You really should do more research before you post blogs like this,” and, “You don’t know what you are talking about!” My favorite, I think, was, “You need to go get some more degrees!” (Sorry. Ain’t gonna happen. I’ve got plenty of learning left to do, but I’m done getting ‘lettered,’ as another commenter in our blog put it.)
In my last article, I also quoted the esteemed Dr. Joe Lstiburek (who also doesn’t need any more degrees) and referenced research on the topic by the Florida Solar Energy Center. This isn’t just my idea, you know. It’s basic building science.
Today, let me just say that home builders in Georgia, as of 1 January 2011, cannot install power attic ventilators in the homes they build. Well, OK, that’s not quite correct. Builders can install them. They just can’t give them any electricity from the power company. Here’s what it says in the Georgia State Supplements and Amendments to the International Energy Conservation Code (2009 Edition):
403.10 Power attic ventilators. In new construction, power attic ventilators shall not be connected to the electric grid. Power attic ventilators connected to a solar panel are allowed.
You can download and read the document (pdf) yourself if you’d like. You’ll find the above passage on page 13, near the bottom. This is basic building science. It’s not something like, say, crawl space vents, that’s based on speculation without any research behind it. And that part about solar-powered attic ventilators being allowed was mainly a compromise, from what I understand. They can create the same kind of problems as their grid-tied brethren and should be banned, too.
So, if you’re a home builder in Georgia or looking to get a new home built in the state, be aware of this new provision in the Georgia energy code. In my opinion, this is a great advance for homebuyers here and is another way that Georgia is leading the United States in applying building science to home building. As I wrote recently, you’re free to disregard the laws of building science. When building science becomes state law, however, it’s a bit harder to get around it.
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I’m liking GA even more. It’s
I’m liking GA even more. It’s too bad some builders don’t bother educating themselves in matters of building science. If they did, we wouldn’t need laws like this to protect unknowing homebuyers.
David: Yep
David: Yep. Georgia’s leading the pack in putting building science into the energy code. Another biggie that I’ll remind people of when the cold weather comes around is that we no longer allow electric furnaces in new homes.
Thank God for FSEC. Georgia
Thank God for FSEC. Georgia has been years ahead of Florida since mandatory duct testing… Florida has had Energy Statutes on the books since 1994, unenforced. We laugh at Energy STATUTES down here! We have a Sentor introducing a bill “Freedom to waste energy in light bulbs”. A very big issue for a Senator trying to prevent economic collapse…
The code is great, but it’s
The code is great, but it’s all about the enforcement. Although the new code is a huge step up, the last one was actually pretty good as well, but there is just so little compliance and enforcement. I see way too many homes that just miss lots of code requirements – the builders don’t know (and sometimes don’t care) and the inspectors either don’t know or don’t have time to focus on enforcing the requirements. And then we have the issue of how all this applies to existing buildings – lots of gray areas there to figure out.
What I used to miss most as a
What I used to miss most as a transplant from the Atlanta metro area to the Lehigh Valley (PA) was real BBQ and the warm and friendly people of Georgia. Your recent posts about the GA requirment to have real third party duct testing and banning attic vent fans in new construction adds yet more to the list of “things I wish we had in PA” – enlightened code officals. This part of SE PA is very much on a lower rung of the energy efficiency ladder. The majority of local builders what nothing to do with energy efficiency. “I ben doin it like this for over 20 years…” is high on the list of reasons they give when you try to explain why energy efficiency can help sell homes in a down market.
Although PA included the 2009 IRC/IEEC in the state building code as of 1/1/2010, actual enforcement is spotty. Maybe that is because of lack of training. One code officer told me that his training was a single morning training session. Even so, a number builders, bouyed by the recent repeal of the residential sprinkler law, are lobbying to change the way the state building code is updated and to allow local opt out of whole sections of the state code.
It is “interesting” to be an energy auditor and energy efficieny consultant in PA.
I can only hope the recent entry of several national builders commited to the HERS labeling program introduced in Orlando will help move our local market toward more energy efficient homes.
Susan B.:
Susan B.: FSEC has done some good work over the years, and if you want to know the truth, Georgia has plenty of unenforced provisions in our codes. I’m sure some builders are installing power attic ventilators even now and the building inspectors aren’t catching it. See the comment by Carl (the Green Curmudgeon).
Carl the Curmudgeon: Yes, it’s true, but at least we have a good code that can go unenforced. Some builders will still do things that violate the code, but some will actually abide by it, and some inspectors will enforce it.
Anthony H.: The issues of enforcement and building inspector education are nationwide, I believe. We have a lot of new measures in the energy code this year, and there’s no way we’re going to get close to 100% enforcement. But this is a gradual process, and I think homes will improve overall.
It sounds like putting air on
It sounds like putting air on the top side of the tire… did the solar power vent industry lobby got a hold of the state code officials? I’ll bet all the solar power vent salespersons are “promoting” their product as safe since the code “allows” it now.
Armando: I
Armando: I’m sure there was probably some lobbying by the solar folks, and yes it’s unfortunate if they’re promoting solar-powered attic ventilators as safer because they’re not. Well, they are if they move less air, but their main advantage is that they’re cheaper to run. That doesn’t necessarily make them cost-effective, though, because they cost so much to install. I hope that in a future edition of our energy code we’ll be able to get rid of them, too.
Very interesting and makes a
Very interesting and makes a lot of sense. I have to agree that more powerful fans and installing them without consideration of the entire envelope can be a very bad idea (less efficient, fire hazard, etc). However, (don’t beat me up, I’m learning here:) if installed properly taking into consideration this educated point, couldn’t fans still be of benefit for those that can’t afford foam?
If the sucked air pulls from the path of least resistance as the research says, wouldn’t that mean that the home would not necessarily need to be air-tight but more resistant than soffit air for the fan to be of benefit? For instance: with weather stripping on a properly installed attic access with properly opened soffit vents and baffles?
Thanks again for posting, I love learning about new research and tech and this dialogue is absolutely wonderful!
Anthony – A few
Anthony – A few clarifications about the testing requirements in the GA Code: They do not need to be 3rd party. Anyone with approved training (A 1 day course) can do it – the builder, the HVAC contractor, etc. Also, there are ways around the testing: For the blower door you can substitute a rough inspection air leakage visual inspection (which can be of ranging quality), and for the duct testing, it isn’t required if all ducts are inside the building envelope (A good practice)
I would sure like to hear a
I would sure like to hear a lot more comments about this subject. Many of the people I deal with live in houses with no central air and have (at most) a small AC in the bedroom and more generally not even that.
They also tend to have lousy or little attic insulation, and are in climate zone 4 or higher.
I confess that for some single story structures in these circumstances I have recommended 1 or 2 small attic fans (one at either end) to pull in air from the current cooler side of the house during the summer (a main switch and thermostatic switch for the fans).
I will tell you that under those circumstances the house does indeed
get noticeably cooler at an insignificant cost. To the extent that the attic plane is leaky so much the better as it draws a small amount of air from the house itself and the open oven in the attic effect is reduced.
I have been in a number of old houses in the south and the very tall ceilings and open central hallway produce a great stack effect – ditto for whole house fans run in the evening/night during the summer time. I claim that old and older houses have to be handeled with more care than what perhaps coulda/shoulda have been done originally.
I would love to have someone like Joe Lstiburek blow holes in this approach.
@Erik, you might want to take
@Erik, you might want to take a look at Allison’s previous article on this topic (linked in first paragraph), as well a comment about PAV’s I wrote in another forum.
Erick: As
Erick: As David Butler already said, if you read my earlier article and his comments, it should answer your questions.
Curmudgeonly Carl: Thanks for reminding us that the inspections don’t have to be done by a third party. Regarding the visual inspection for air-sealing, though, it’s not as easy as you make it sound. It has to be done by a “third party ICC Certified Residential Energy Inspector/Plans Examiner” or equivalent. I don’t know how many of those are in Georgia, but I suspect there might be more HERS raters.
t hardy: Actually, in those old southern homes with high ceilings, the stack effect works in reverse in summer. Warm air won’t rise up into hot air, but cool air will fall out of the bottom of the house, pulling hot air in through the top. In the cold climate homes with no AC that you describe, it sounds like they’re using the PAVs as whole house fans almost. That’s fine if they’re not bringing in moldy air from the basement/crawl space.
David B.: Thanks for the reminder about your other comments on this subject.
It’s great that GA is getting
It’s great that GA is getting some pats on the back, as opposed to the usual stories about school cheating and the like. These progressive measures are in the code because building science experts were actively involved in crafting and educating officials for the code adoption. I hope GA and other states can serve as examples of what can be accomplished if you get involved in the process. As they say, making sausage is never pretty, but hopefully a progressivly better product comes out every time. In GA, Southface has been on the committee for over a decade and is now working, with others, to train the workforce to implement and enforce the 2009 IECC with amendments.
Sydney:
Sydney: Welcome to the EV blog! Glad to see a comment from you here. You’re absolutely right — having some good building science advocates involved in the energy code process is crucial and is the main reason Georgia is a leader in the country. Did you see the article I wrote about Mike Barcik last year when the new code first passed?
I would like to see the
I would like to see the manufacturers of the PV attic fans comment and respond to this. Nearly all of the insulation/radiant barrier contractors in North Texas- my competition- tout the greatness of these solar fans in making your house cooler in the summer. They do it to make a buck but most truly believe….
Steve: I’d
Steve: I’d love to hear what they have to say, too. If you know any, send ’em over here to have their say.
In Alabama and Florida we
In Alabama and Florida we have many companies that sell radiant barrier rolled on attic floors, solar attic fans, remote controlled supply register restrictors to reduce HVAC air in some rooms…. and the chamber of commerce, BBB, …do nothing. There needs to be national consumer protection on energy, and building inspections done correctly for new and retrofit improvement or consumers will waste their money and it will take longer to get what works done. There is SRCC for solar thermal because of the huge number of bogus products and bad installs of solar water heaters in the 1980s before the SRCC. Please learn from the past.
&
Attic venting Blog, 30 August, 2011
An associate suggested I respond to this discussion. I believe that the Georgia State Amendment to the Energy Conservation Code 2009 in regard to attic ventilation is a mistake and will be repealed on down the road. Relying on convection and solar powered vents will not serve the public good. Anyone that believes that heat gain and moisture retention in the attic is useful is mis-informed. My own attic is a case in point.
I built my house fourteen years ago. My house has a large attic with two gable end vents on either end. The first two summers I ignored the heat to the detriment of my shingles and items stored in attic. I installed static vents fifteen feet apart. While up on the roof, noticed the heat damage to my new shingles. The added static vents lowered the attic temperature and my cooling bills dropped nicely, I ignored it.
Ten years of consistent summer power bills incurred until I installed two power vents that I designed to stop ember entry for the West Coast market. I set them in my attic to test my design before sales to the public. My power bills have dropped an average of ten dollars per month. I am thinking of setting a third unit at the other gable end. These units run well into the evening removing unwanted heat, which a solar powered unit would not. My ceiling penetrations are sealed off from the attic, so I do not worry about extracting my conditioned air.
Centrally heated and cooled homes, with properly installed HVAC systems, should create a slight positive pressure in the conditioned space. So if the augment against a slight negative pressure in attic or crawlspace is that it will suck the conditioned air out, I would have to say, the positive pressure from within would have caused the very same problem anyway. It would seem that this problem with negative air pressure is more about poor construction techniques than heat and moisture removal.
The one saving grace to the new code for power attic vents is that it only applies only to new construction, as I read it. There will not be to many new homes built in the next ten years, so the damage will be limited and revisable. The best building science is one that works and does the least harm.
Sincerely,
Mike Martin
Licensed: Electrician, Plumber, and Real Estate Broker
Owner of: Vent the Crawl
Ventthecrawl.com
Craig: <
Craig: Caveat emptor (Let the buyer beware) should be everyone’s motto. The government, the Better Business Bureau, and the Chamber of Commerce aren’t going to protect you. There are plenty of perfectly legal products installed or used improperly. One of the reasons I write this blog is to warn people about the bad stuff people are trying to sell them.
Mike M.: Since you sell power attic ventilators, I’m not surprised you think this new part of the energy code is a mistake. Building science is not on your side, however. PAVs are bad for homes. (Since your main product seems to be fans to ventilate crawl spaces, I guess you probably don’t want to hear what I have to say about that.)
Well, I agree with you about
Well, I agree with you about the GA is America’s leading state in the field of building science in home builders. It is good to follow the law and nowadays there are some good solar attic fans in the market. It is keeps the house cool and they are good as well.
Whole House Attic<
Whole House Attic: Solar powered attic ventilators have many of the same problems that grid-tied PAVs do. In addition, they’re almost never cost-effective to install because the actual savings are so small. As I’ve said before, improving the building envelope is the way to go, not power attic ventilators, even if they’re solar.
The problem is solar power
The problem is solar power attic fans are basically worthless as far as real CFM ratings go. Does anybody actually believe that a 20 watt motor can move 800CFM of air blowing into a solid dome? They seem to be about the only people that are getting 40CFM per watt. A standard A/C powered fan using 400W to get 1200CFM is only 3CFM per watt. Somebody is exaggerating ratings…
If new construction I’d just seal at the roof-line, make the attic conditioned space. For retrofit on current homes I can see doing an A/C power roof fan if you get one with a PSC motor (uses 1/2 the power of shaded pole motors) AND you have plenty of intake ventilation. In breezy parts of the country the “whirlybirds” are just as effective as power fans and don’t require any power to operate.
Much ado about nothing. Why
Much ado about nothing. Why shouldnt a property owner be allowed to do whatever he/she wants on their own property if it does not harm others.
There is never a one size fits all for these types of debates. There are dozens of factors involved in calculating theoretical performance, many of them are not at all accurate. My studies and research on these subjects, including development of solar equipment since 1967 gives me a great deal of experience to fall back on. If you think a certain appliance will be a positive factor in your environment or provide a savings, invest in the product and try it. You have the option to remove it and sell it on ebay.
We have so many experts getting paid a lot of money to tell us what we need to do when in fact we are our own best friends when our lives or pocketbooks are are at stake.
I refer to the banking and investment industry. Listening to those idiots has cost us more than any collective errors in judgment in whether to install a power vent in our attic.
Samuel H.:
Samuel H.: Ah, I see. Because the finance industry is corrupt, no one should trust anyone talking about building science. That’s quite an extrapolation.
You also said:
Why shouldnt a property owner be allowed to do whatever he/she wants on their own property if it does not harm others.
Gosh. Where do I start? If you read this article and the one I linked to in the first sentence, you’ll see that power attic ventilators can harm people. More generally, we do give government the power to regulate so that people don’t do stupid things. Yes, we can discuss bad examples of how they apply this power, but keeping people safe in homes is well within government’s purview.
Finally, you said:
If you think a certain appliance will be a positive factor in your environment or provide a savings, invest in the product and try it.
The Georgia energy code doesn’t stop people from doing stupid things with their own houses. It stops builders from doing stupid things to houses they sell to unsuspecting homebuyers.
Id just like to chime in here
Id just like to chime in here by quoting someone I consider a far greater expert on the subject than myself, Paul H. Raymer,from his book “VENTILATION HANDBOOK- Ventilation to Improve Indoor Air Quality”,
“As with many technologies, layered in tradition, eventually these original purposes were forgotten, particularly in cooling climates where ice dams are not an issue. The thought was that attic venting could lower the attic temperature, which would reduce the cost of cooling and prolong shingle life even though there was no research to support those concepts. Adding an active cooling system or fan was assumed to amplify the effect, but field testing has shown that the temperature of roof sheathing of a [sic] unvented roof will rise by a few to no more than 10°F more than a well ventilated attic. Despite this, shingle manufacturers generally insist on the vented deck design and most codes require it” Chapter 16, pg 199
“In terms of the effect of the cost of cooling the air in the house, reducing the attic air temperature has only a small effect. Warm air flows upward. The hot air in the attic will not flow down into the house. In terms of conduction, if the floor of the attic is poorly insulated, the ceiling of the house will reach the same temperature as the attic, and that heat will be conducted and radiated into the house. You can feel it if you stand under a poorly insulated attic hatch. If the floor of the attic is well sealed and insulated, then the attic temperatures will be isolated from the house, and the large temperature swings up there are less important” Chpt 16, pg 201