ReplyKenny, I think you will get little argument here about using square footage methods for load sizing! That was my whole point.Originally Posted by kenny mac
I'll be waiting for your tread, and maybe a copy of the load calc.
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I wanna see pix
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Kenny, I think you will get little argument here about using square footage methods for load sizing! That was my whole point.
I'll be waiting for your tread, and maybe a copy of the load calc.
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a well insualted home indeed, but you and paul would be good at convincing women 4 inches is 6ROFLMAO
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Whoa....the only thing I wanted was for you to go about your selling approach slightly different. I believe in your product. I just didn't want to see you turn customers away because of the quick reactions.
I do not doubt the product and I want everyone to go as green as their pockets allow. I was even questioning if there were people around my house or if this had commercial potential....working for a large RE management company and all......that trully wants to be the leader in the green push for rental income. If you were at the last green meeting we had you would understand.....Companies are willing to take losses right now to be thought of as green because people are buying into that concept full blown.....not that it's over blown.
A different perspective then you might have thought how I was looking at it......think commercially if you could use 1 1/2 ton systems instead of 3/4 ton systems.....on buildings with 100,200,300 units. Not un-realistic at all.
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Sounds like you are guessing here ken, or did you take a stab at measuring this?
With a sealed attic you at least have a shot at this order of magnitude
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I saw that, maybe .08-.1 would be closer?
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It looks to me like you guys are guessing !!!
How do you guys get your ach, achn, sal, mlr ???? You guess ???
Do you have or practice Blower Door Testing ???
The method of ACH you guys use is a pie in the sky.... by volume (ie) the bigger the home... the smaller the hole.....
We have to use SAL (Surface Area Leakage) ACH 50 with a Blower Door to get precise measurements of leakage (Energy Star Home).
Yes, I understand we all guess at the ACH when doing a Load, but until you have some experience in SAL (Blower Door) Your Manual J Calcs are not legal.
Could we all agree (i am guilty as well I don't test every home) you must do a Blower Door Test after construction for our Manual J's to be legal ??
My home tested at 750 cfm50- (neg. pascals) two rings, with a SAL 25600 sqft = .0292
Sorry this was a THT (tape home test) in other words all the designed leakage was taped off...
And yes we mandate and practice ASHREA 62.2 in all of our homes.....
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Ken, you make outlandish claims so you need to back up what you say.You have an exaggerated house due to the attic and a lack of windows.
You are basically taking the blower door test, dividing by 20 and using the volume of your attic.
A standard value for R2000 homes is 0.07 ACH, and these homes are up against cold climates. Desner cold winds, bigger temperature differentials than Georgia There have only been thousands of blower door tests on these homes going back almost 30 years now.
Due to the Northern Climate it is easier to get the R2000 homes that tight due to the rules on vapour barrier placement, but in a southern climate, the only shot you have at being that tight is a sealed attic.
Any heating system calculated to CSA F280 or any version of ACCAs manual j for these houses will be conservative. A lot of these homes incorporate passive solar and you never get a service call until after the sun has set as the sun can pretty much heat a lot of these homes. The infiltration allowance and below grade losses allowed for in the calculations are a little conservative plus internal gains help out as well.
Yes it is pretty hard to blower door test a home before it is built, but every R2000 home is blower door tested after it is built as part of its certification process. I only asked if you measured it as your statement sounded like a guess.
I have been using a tracer gas approach on a concrete home with a sealed attic and I am coming up with ACH of the magnitude that you are talking about. Except if the rate is that low, then my ears should pop when the clothes dryer runs and they are not, yet I have it recorded every minute how a concentration drops and it is on the windy side outside.
Your claim to fame then is your wall system, you spray a little bit of foam into the wall cavity to get the air tightness then you use less expensive cellulose. You should be more econnomical than icynene
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Who are you ???
Several of the guys I have worked with have done some tracer gas testing, Tooley, Lsteburik, Winter.
Don't quite understand why, other than pressures and permeability of vapors Would it be relevant to a closed cell foam encapsulated home and the foam being 1 perm.
What ? Concrete has a perm rate of a gozillion?
I think the R-2000 home has to do with Canada don't it ???
Is tracer gas the method of testing the r2000 homes ???
Can it help locate the voids, how costly and is there a standard of testing ?
Sounds interesting !!!!
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I am just a canuck relocated to the tropics with some observations and opinions.
A blower door will allow you to estimate your leak area, tell you you have leaks, help you find the leaks but beyond that, my gut feeling is that we are talking about a basic fudge factor to come up with a conservative infiltration rate to use.
About the only time I would really worry about how permable a building section is, is when you have an indoor swimming pool in the north.
R2000, CMHC, what they were doing in Sweden all predates Building Science.
The R2000 homes were the cutting edge of northern housing technology back in the early 80s. There was the next 'diminishing returns' step beyond that called "Advanced Home", I worked on about the last prototype house in that series, then a change of government and a loss of funding.
A couple things about vapour barriers.
1) When applied in the wrong loaction they are a disaster
2) Allthough they are designed to stop vapour diffusion, they also stop air and all the mositure travelling with the air. You put in the barrier and get an air tight house.
I get high dewpoints where I am right now, it will average in the high 70s for 6 months of the year and you can get days in a row where it averages over 80.
Again, in my opinion, the amount of moisture that wicks through a wall is insignificant if it is allowed to evaporate to the dry room air. The moisture has a path out, sort of like Dr. Joe saying once a wall gets wet , you have to give it a way of drying out. So the open cell does this, but I do not think the closed cell will.
So concrete is permable, and I find its permablility to be insignificant.
My intereset in tracer gas is to work out exactly how much air does move through a structure. I noticed you quoting 62.2. If you read through 62.2 you will also note that it assumes you are getting 2 CFM of infiltration for every 100 square feet, which I know is not occuring in the concrete home and if your house is as tight as you feel it is, you are getting no where near that amount of infiltration either.
So then it is probable that levels of CO2 that the CIH types worry about are not detrimental enough to cause brain damage as you sound fairly articulate.
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a link on R2000
http://r2000.chba.ca/
it explains my smart ass comment about "what Canadians knew 30 years ago"
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Tracer gas approach, well I am going to compare my approach to
ASTM D6245, D1356,D3249,E741
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("I feel like Larry the Cable Guy")... are you accusing me of having brain damage???
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no, you sound smart, you said you followed 62.2 but you have less fresh air then 62.2 assumes,so it proves that CO2 does not cause brain damage
Last edited by Carnak; 07-14-2008 at 12:15 PM.
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Just go outside and look for the missile sticking through the roof after the hurricane and you will find the source of your leak
At least you will still have a ceiling.
Your neighbour with a vented attic will lose his ceiling before the roof fails with a major storm as water will blow up into the soffit vents, saturate your insulation and bring down your ceilings. That is a fact jack and not a 'what if'
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A sealed attic with about R20 sprayed on the underside of the deck, with any gable walls insulated will outperform R49.
R49 is just going to filter the hot humid air as it passes through to the conditioned space below.
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