We recently had another office building constructed at my place of work here in the Virginia mountains; typical commercial construction; slab on grade, metal studs, metal sheathing, insulation board, etc. When the wind blows at a speed of about 15 MPH or higher the amount of air infiltration is so great that entry doors on the leeward side of the building won’t close without considerable extra effort. Offices on the windward side fo the building feel drafty and cold. I can only imagine what this sort of energy usage this air exchange rate results in.
My house also suffers from what seems to be excessive air infiltration. The owner/builder obviously cared about energy efficiency as he used 2×6 construction with insulation for exterior walls and invested in well-build and energy efficient windows. However, when it came time to seal the house up after sheathing and installing windows and doors, a poor job was done. A house wrap was used but poorly installed and seams weren’t sealed. Windows and door frames weren’t sealed well either.
I’ve also seen discussion (in FHB I think) where air infiltration is cited as a major source of energy loss in houses; even typically greater than that caused by poor insulation. at least with current standards of insulation.
So here’s my question. With the price of energy increasing rapidly and expected to stay high, and lots of talk about energy conservation, and oil independence, etc. why aren’t there higher standards (by code or otherwise) for building construction with respect to air sealing.
I’ve had local builders tell me that they found that they were building houses too tight, resulting in sick building syndrome. I understand that concern, but wouldn’t it be better to build an air tight house and then install a heat recovering ventilation system so exchanged air could be metered and filtered. I also think the added costs to seal tightly would be quickly recovered in decreased energy costs.
What am I missing?
Replies
What am I missing?
Nothing. You got it. Other than the ventilation system, which you will probably do considerably shopping before your find an HVAC guy who's more than HAC.
Tight happens, just not very often. 15 mph isn't much wind on this Va mountaintop and we don't have your situation. Using some fixed windows, rather than operable, will save enough to pay for a small air system. We do .5 ACH, filter the incoming air, and have indoor air quality often noticed by guests. Comfortably rely on a passive heating/cooling system.
It works.
PAHS Designer/Builder- Bury it!
Ditto what VaTom said.
Also, the key to understanding the value of a tight house is how the air exchange is taking place. On average houses it's going through random cracks that are the path of least resistance. Hardly a good method of deciding anything.
In a tight house it will take fewer air exchanges to have equally good air quality. By loosing fewer air exchanges through random cracks, more air can be taken out of the areas that need it--the kitchen and bathrooms. In some areas Habitat houses are amoung the tightest built as judged by blower door tests. What they have found is that a super-tight house can still allow enough air in through various unavoidable cracks to keep air quality quite good.
Good quality bath exhaust fans are used that have dual modes. One mode is the familiar on/off, while the second mode is a lower CFM, variable speed that is constantly running. For each individual house the constantly running fan is adjusted as the seasons change to ensure enough air exchanges for good quality air, but not enough to needlessly waste heat/AC.
Even more air can be replaced with an air exchanger that preheats the incoming air with the heat contained in the outgoing air. If the ultimate indoor air quality is your objective then this is the way to go.
Unfortunately, evidence provided by Habitat indicates that in identical houses equiped the same, except for one having an air exchanger and the other the dual mode bathroom fans, the air exchanger won't save enough in energy bills over 30 years to pay for the high upfront costs.
Beer was created so carpenters wouldn't rule the world.
"Unfortunately, evidence provided by Habitat indicates that in identical houses equiped the same, except for one having an air exchanger and the other the dual mode bathroom fans, the air exchanger won't save enough in energy bills over 30 years to pay for the high upfront costs."
Nobody should need a study to figure that out. The heat exchanger costs to buy and operate. None have 100% efficiency and are usually run non-stop. What you get for your money is better overall indoor air than simply exhausting bath air can do. They really have very little to do with each other. My faith in Habitat remains (skeptical).
BTW, I cobbled my own heat exchanger from Pop Science plans. Cost about $50 material and is upwards of 90% efficient, by my crude measurements. I use unequal fans to slightly pressurize the house, ensuring that all leaks go out. Works extremely well. PAHS Designer/Builder- Bury it!
My faith in Habitat remains (skeptical).
I also was skeptical of how Habitat builds houses until three years ago when I attended a rocky mountain regional workshop. While there were many areas discussed I only attended the building science and construction sessions and what an eye opener.
Individual Habitat chapters have a huge amount of discression of how they build so overall I wouldn't bet on the best construction as related to building science. However, the recommendations from the national rep were top notch.
In the more progressive chapters the houses are all blower door tested and efforts are made to make the structure as tight as possible. Spray foam is provided free of charge and labor is free so just about every crack and corner can be filled with no increase in overall expense. Also, ridgid foam is supplied free of charge from Owens Corning so a great deal of it is used.
... I've been instructed to cut this short and go christmas shopping. :-)
Beer was created so carpenters wouldn't rule the world.
<What they have found is that a super-tight house can still allow enough air in through various unavoidable cracks to keep air quality quite good.>As I understand it air quality shouldn't just happen it should be created. This is the way I think about it. A high performance house is like a high performance car. I wouldn't take my BMW out back and lift the hood myself nor would I let good performance to just happen. I would take it to the BMW certified dealer who has the proper diagnostic equipment.A good Web site (a little heavy) is http://www.buildingscience.com.jross -- FH Editorial
http://www.sipbuilding.wordpress.com
As I understand it air quality shouldn't just happen it should be created. This is the way I think about it. A high performance house is like a high performance car. I wouldn't take my BMW out back and lift the hood myself nor would I let good performance to just happen. I would take it to the BMW certified dealer who has the proper diagnostic equipment.
I'm not entirely sure what your message is. Is it that you think high performance buildings are out of the technical reach of most builders? I can't disagree more.
You are correct that air quality shouldn't be left to chance, but that doesn't mean it's rocket science. It's different from traditional housing, with it's own list of idiocycracies, but in many ways it's a simpler way to build.
For instance much less time is spent planning how to keep temperatures at a comfortable level. Really good insulation evens out temperature swings so much that even a poorly thought out system can work quite well.
Moisture mitigation is a prime concern, but a high performance shell allows simple effective venting of the bathrooms and kitchen to handle the majority of moisture problems.
Habitat encourages chapters to install passive radon venting for all all crawlspaces or slabs. The gravel is already there. A well sealed vapor barrier is already there. All it takes is a 3" pipe running up through an interior wall and exhausting out the roof. The air in the pipe is warmed and wants to rise creating a slight vacuum to vent off not only radon, but also all the natural and not so natural gases that rise out of most building sites. Simple solution for increased air quality.
I blame those who are making a living off of air exchangers and other high-tech routes to high performance building for creating a number of half truths and exagerations that suggest their (expensive) solution as the only real route to energy efficency or air quality.
Shame on those who proclaim some complicated and externally strange looking house design as the right way to take advantage of solar. Many of the high performance houses we've built use basic overhangs over windows sized to take advantage of the sun in winter and block it more in summer. Instead of an odd looking solar house, ours have been attractive, normal looking structures with slightly larger windows in some areas and smaller in others.
So much emphasis is placed on the ultimate design to hold heat during the day and release it at night, with fancy diagrams and plans thought up in someone's head more than what's really practical. Effectively increasing thermal mass can be as high tech as adding extra concrete to floors and walls.
We aren't talking about BMWs, but rather the humble Geo Metro. It's energy efficent because it does some basic things very well and doesn't have bells and whistles to weigh it down.
Good building.
Beer was created so carpenters wouldn't rule the world.
Ok the car analogy was a little off. Here’s the point. New houses are high performance houses and we can’t expect to keep them working properly if we use the same methods we did twenty years ago
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<Is it that you think high performance buildings are out of the technical reach of most builders?>
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Absolutely not. Just the opposite, but we do need to raise the awareness level. As we demand more from our structures, the mistakes that we make may cause bigger problems.
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<Moisture mitigation is a prime concern, but a high performance shell allows simple effective venting of the bathrooms and kitchen to handle the majority of moisture problems.>
<!----> <!---->That’s true but if the fans are just wired to a switch on the wall instead of a humidity sensor, or at the very least a timer that switches on at regular intervals, the building has a higher chance of getting sick. jross -- FH Editorial
http://www.sipbuilding.wordpress.com
Ohhhhh... My misunderstanding. Sorry to sound defensive. I've been working too dang much.
Happy holidays.
Beer was created so carpenters wouldn't rule the world.
I made a good faith effort to look at the building science website you listed and it's a perfect example of over designing for profit and under performing. They do have some good information, but much of what they argue against is simply poor building practices, not anything revolutionary.
"A high-performance, energy-efficient house depends on rational and efficient space planning."
I'd prefer to design a high performance shell and let the client decide on space planning that works for them within that space.
The cold climate prototype house they are so proud of has, "R-38 Attic, R-35 Cathedral Ceiling." Some of those design dollars should have been spent on R-60 attics and cathedral ceilings above R-40 with polyurethane foam. Insulation is cheap.
Beer was created so carpenters wouldn't rule the world.
in most cases, the ceiling is not the primary place to start reducing heat loss. R38 is pretty good. If it's a choice between different measures, I'd prefer a client to focus on glass reduction or glass performance improvement (maybe some nice thermal curtains for those passive solar windows).Pointing at one aspect of an overall design and saying it's not perfect doesn't say much about the overall design. Heck, why not R-120 ceilings? Those bastards!-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
""So here's my question. With the price of energy increasing rapidly and expected to stay high, and lots of talk about energy conservation, and oil independence, etc. why aren't there higher standards (by code or otherwise) for building construction with respect to air sealing.""
Because it costs a few bucks more and the people building the vast majority (say 99.9%)of housing in this country are all about the $ , and if it costs a few bucks more they will fight it tooth and nail.
It is called the power of money , played out by special interest groups for the $ involved.
As far back as the late 1960's most of the energy saving information and technology has been available, but utilized by only a few.
Figure out how the McMansion and tract builder can make a few more bucks doing it in tract sub-divisions and it will sweep America overnight.
They won't even pay to have things done correctly as is. Petal to the Metal and don't look back .
Of course now the client does have a say in all this,they won't pay for it, and mostly all they care about is the glitz and glitter anyway .
Might as well ask why you can't buy hand crafted furniture at Wallie World. Because the customer won't pay for it to be sold there.
Edited 12/7/2006 12:03 am ET by dovetail97128
So, would the establishment of air infiltration rate "standards" be of any help; something like EPA;s Energy Star program.
I'd hope that if a home buyer had a choice, they'd spend a few extra bucks to get a more efficient, healthier, less drafty house. A lot of people out there are making a lot of money selling indoor air cleaning systems. a lot of pollution, especially plant allergens would be coming in from outdoors.
I suspect so . Today's housing is much more energy efficient than it was 30 yrs ago. Of course on the down side to that today's houses are also much larger than those of 30 yrs. ago so as for total energy consumption per unit I wouldn't be surprised we are at a wash.
Building codes have progressed a lot in terms of addressing these issues and I believe that the closer we get to another real energy crisis the more the codes will address it.
We have a program for energy efficient houses here in Canada. It includes air infiltration rates, which must be tested with a blower door, in order for the house to be certified.
I just googled R-2000, and there is a web page.
I took the course 20 years ago to become R-2000 certified. I think there was one R-2000 house built in our small town, but have not heard of one for years.
I built my own house to r-2000 standards, including the blower door test. I also have an HRV (heat recovery ventillator), which is rarely turned on. The dehumidistat never turns it on. It is coupled to timers in the bathrooms, so is really used as an expensive bathroom fan.
My problem with the r-2000 program is that it is coupled with the new home warranty program. This makes it difficult for a small builder to compete. Warranties are mandatory here in B.C.
Anyway, if anyone is interested in the standards, I think they are on the website.
Goldenboy,
There was another program more like what the original poster was suggesting, a voluntary, subsidized program to rate houses both new and old by their energy consumption. The conservatives killed it just days before I was scheduled to have my house tested.
The program inculded an assessment of the house, a schedule of suggested improvements to reduce energy consumption and a re-assessment. I'm hoping our next government will reinstate the program.
Besides the immediate usefulness of knowing where you stand, a consistent rating system such as this could provide a financial incentive to people to make the extra effort to build houses that are more energy-efficient in that a good rating could be reflected in a better resale value.
R2000 is quite another thing. It is a list of goals which, if achieved, get you the R2000 stamp on your house. The air infiltration goals are usually achieved through special attention to sealing the air/vapour barrier and the the housewrap as well as a heap of other things like insulating headers and end joists, sealing wire and pipe penetrations through top plates, special techniques of sealing electrical boxes and endless freaking details.
R2000 has nothing to do with improving the stock of houses in general, only with certifying houses built under the program and with promoting business for the builders who participate. R2000 houses do usually get a better sale price per square foot than similar non R2000, I hear.
Ron
R2000 has nothing to do with improving the stock of houses in general, only with certifying houses built under the program and with promoting business for the builders who participate. R2000 houses do usually get a better sale price per square foot than similar non R2000, I hear.
Ron:
The R2000 and its predecessor, The Super Energy Efficient House (SEEH) program, were intended to help improve energy efficiency and indoor air quality of the stock of housing by means of leading by example. But....Canadian builders in general are apathetic, resist change, do not retrain, and blame the government for their own inadequacies!! So the R2000 program really did not succeed here as intended. But Japan licensed it from us in 1992, Joe Lstiburek (a Canadian who was involved in its infancy) took the concepts to the US and the "Build America" program, and the US Lung Association essentially requires an R2000 house as the basis for its "Health House" program (Note: In its beginning, the Minneapolis Chapter took the concepts from the Manitoba R2000 program)
The Canadian National Building Code (NBC) now reflects some of the innovations in R2000 houses from the early 1980's such as airtightness and whole house ventilation. The NBC does not have a process for measuring/certifying its intent and so our general housing stock is lacking in the energy efficiency envisioned by the first developers and promoters of SEEH and R2000.
I was a site advisor/inspector, researcher and "troubleshooter" for the New Brunswick R2000 program from 1983-1993. Two of my client builders in Moncton were named Canadian R2000 "Builder of the Year" in 1989 and 1993. It was really frustrating to see the NBC flounder with energy efficincy in housing. Indoor air quality, high humidity, mould and rot problems developed due to regular builders building tighter houses (by copying R2000 airsealing techniques but not taking the courses) and then refusing to pay $2000 for a whole house HRV system and only installing a couple of venting bath fans. These houses ("built like R2000") failed and, of course, the R2000 program was blamed. Hell, even Mike Holmes has disparaging remarks about R2000 houses!!! Does he know how good a certified R2000 house is??
Yes, a certified R2000 house commands a higher price to a knowledgeable buyer. But how many knowledgeable buyers are there? FEW!!! In 20 years of prepurchase house inspections, I have only inspected 2 R2000 homes. This low number is also influenced by the trend found by realtor research (that testifies positively for the R2000 program) that owners of certified R2000 homes don't tend to sell them. They are quite happy to stay where they are!!
Brian,
It might surprise you, but I agree with what you said about R2000 houses. They do lead by example though it might not be to the extent that the originators hoped. We have even been forced to use many of the same air sealing techniques in renos (which I think can be nuts, but that's another story).
Where we differ on R2000 houses is that I think houses built in the most common way, with wood frame/foam sheathing/ sheet metal wind brace are too flimsy to waste the time and energy tossing them up. I predict that these houses will not outlast their first mortgage. Building a house that lasts is the first and biggest step toward energy conservation in houses.
I think that a recognized program to test and rate houses by their energy consumption would go a long way toward encouraging low-energy houses. If there was a single number a buyer could look at and use to compare one house to another, the energy consumption of a house would be a more important factor in a decision to buy a house. But there's no way I can think of to factor in the longevity of a house in the absence of wisdom.
Ron
(My telephone bill is twice as high as my heating bill. Why? ICF)
Heard today from yet another who was interested in that PS heat exchanger article. He mentioned my using different sized fans to pressurize the house is what they do with M1A1 Abrams tanks for NBC (nuclear, biological, chemical) protection for the crew. Makes the leaks all go out. Incoming air filtered by an NBC filter.
Makes sense, but all I need is a pleated filter from the home center. Good down to 5 microns, IIRC. They're all priced the same, independent of size. I buy the largest and cut it in half: 2 for the price of 1.PAHS Designer/Builder- Bury it!
What am I missing?
An open house this afternoon for the "only houses in the state officially sanctioned by the American Lung Association".
"The homes are built using construction techniques that make them more airtight and come with ventilators and dehumidifiers built into the walls."
http://www.dailyprogress.com/servlet/Satellite?pagename=CDP/MGArticle/CDP_BasicArticle&c=MGArticle&cid=1149192098583&path=
Appears to be some misinformation presented in the article, but our small-market paper hires new journalists who, if competent, soon move up to a larger paper. While a data sheet would likely suffice, I'm going to see what they have.
Meet me for lunch?
PAHS Designer/Builder- Bury it!
"An open house this afternoon for the "only houses in the state officially sanctioned by the American Lung Association".
"The homes are built using construction techniques that make them more airtight and come with ventilators and dehumidifiers built into the walls."
http://www.dailyprogress.com/servlet/Satellite?pagename=CDP/MGArticle/CDP_BasicArticle&c=MGArticle&cid=1149192098583&path="
Interesting. Cost are 34% higher for that house! Seems high to me and very few will spend that kind of extra money. I think there are much cheaper methods to prevent mold growth and promote indoor air quality while saving on energy. I think its more like conscientious and knowledgeable construction coupled with buyer education. However, its very hard for even a knowledgeable buyer to distiguish a well-built, effiecent, healthy house from one no much that way. Many of the features that define such a house are "hidden" as construction progresses. Hency my call for standards, whether volunatary or otherwise.
Tom: Can't on the lunch, not now anyway. My last direct email response to you got bounced BTW.
Crap! I thought my ISP got their mail straightened out. Ongoing problem... I've been trying to find something resembling broadband and have a new feeler out. Can't get satellite internet without a lot of tree removal unless I can convince my TV guy to get certified for internet. He wants more large rocks, so it's a possibility. He put dishes in unapproved locations- for me only.
I digress...
The houses were pretty much as I expected. Infill area that wouldn't have been considered by anybody just a few years ago. Zero guest parking. What was that about: they aren't making land anymore? I'm still shocked at how little you get for $495k.
Horrible project that had one factor going for it, healthy air. Open house was good, well attended. Pounced on by the listing agent of course. We're the right age to have the money, if the wrong age to want to put up with stairs everytime you turn around. We dressed appropriately.
HVAC guy was there. And actually is V knowledgeable. We shared past commercial construction projects/clients and was very happy to talk. Once he realized I wasn't the normal totally uninformed prospect, we got down to some meat. Had to change his pitch substantially, eliminate the fluff.
Soy foam between the studs. .235 ACH with a gargantuan dehumidifier. I didn't ask about the heat exchanger. Got a lengthy brochure that I want to study. The cost you're questioning clearly doesn't have to happen, it's what you get if you don't want involvement, only want to open your checkbook for someone to make all decisions for you. That's the normal route here. Lots of doctor-lawyer-Indian Chief clients.
The last local who approached me from that web page on our place was all excited when I told her what she could have built- if she'd become involved. Disappeared when I mentioned that my numbers would not happen if she simply approached a standard home builder to figure it all out for her. I'm always happy to give out free advice but much time involvement means consultation fees. She disappeared. Maybe when her house sells I'll hear from her. Didn't bother to check her equity/ability-to-pay potential.
HVAC guy's main complaint is local builders who don't offer enough choices to clients regarding the better features of this project. He knows they lack the knowledge to actually do that, but still complains that they don't. Did have a great litany of horrors he's seen of rot and molds. And a couple of things to say about ac/dehumidification that I know are wrong...
There's little good reason for 34% higher costs. Everything I've seen about underground housing says it's at least 10% more costly. Not my experience. The client house similar to ours appraised 50% higher than cost (appraisal comparing it to standard housing). Can be done but somebody has to make the effort. GCs here don't have to. Nor does that HVAC company.
I may spend some time talking with the American Lung Association representative. Didn't get the chance yesterday. HVAC guy thought he had a live one (me). All in all, an interesting open house. PAHS Designer/Builder- Bury it!