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Blower door test/ drafts

Tom_6 Member Posts: 2
Hello Wallies,
I've been enjoying all of the excellant disscussions here on the wall for the past year and a half. I'm a HO with a 1976 cape built with r19 in the walls and r30 in the attic, Its electric heat with a wood stove, and we burn wood for heat. There are wicked drafts in the house which seem to be coming from the "8 vented through the floor to the outside stove island in the kitchen and from the bathroom vent which has a heating element in it to blow heat if wanted. I want to convert the house to radiant floor heat and before doing that I want to fix the leaks. I'm thinking of a blower door test to see where all the leaks are and am wondering if winter is better than summer to do the test? Also will a wood stove create signafant drafts indoors? And will a blower door test be helpfull in doing an accurate heat loss caculation? Thanks for your help.


  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    Blower door tests

    I do quite a few of these and I will tell you this.

    If you are using the wood burning unit for your heat, I would not recommend a blower door test.

    We can either depressurize or pressurize the home to find the actual leakage.

    The fire would have to be completely out and the ashes cleaned from the wood burner.

    Depressurizing the home would pull anything that's in the wood stove back into the house, and pressurizing it could push the contents up the chimney including the fire!

    I would wait for milder weather and then by all means have the blower door test done.

    Hope this helps.

    Mark H

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  • Dale
    Dale Member Posts: 1,317
    Blower door

    Best way to find air leaks. And, as the other post said not to be done with a lit fire. If you do seal up the place ask yourself where will the air needed for the wood burner come from? I think the best way is to bring in needed air from a designed source.
  • Greg_4
    Greg_4 Member Posts: 32
    blower door tests

    We do more in the late fall/winter/early spring than other times of year, I don't know if this is by design or coincidence. Actually, the I.R. camera is more available to our department when summer is over. We do them all year around, but typically we couple the blower door tests with an I.R. camera scan. This scanning is best done in cool/cold weather. The camera helps us "see" points of heat loss and/or cold infiltration. The blower door obviously aids by exaggerating air infiltration conditions. The customer then receives a video from the I.R. camera scan so they can play back at convenience noting where to emphasize weather stripping, caulking, sealing, etc. As you well know, blower door tests are important in other ways. We've found some homeowners have had new tighter windows and/or doors installed and may have 'over tightened' their homes leading to possible back drafting or spillage of flue gases. Greg
  • Bill_3
    Bill_3 Member Posts: 34

    What does I.R.mean.
  • Hugh Mason
    Hugh Mason Member Posts: 24

    I.R.= infrared radiation= the type of radiant energy radiated by objects too cool to emit visible light or even shorter wavelengths like ultraviolet or X-rays. You and every piece of matter in a house emit infrared. Hotter objects emit more of it so an I.R. camera can "see" warmer parts of the outside of a house where heat is "leaking" out or cooler areas in the interior of a house. This type of camera needs a temperature difference to show anything so winter is an ideal time to use them.
  • Tom_6
    Tom_6 Member Posts: 2

    Thanks for your replys. What would i expect to pay for blower door tests and IR video? Anyone you can reccomend in West. Mass? I would use a dedicated air sourse for the stove, would really like to elimanate the cold cold air coming in through the stove island and bathroom. Will these tests do anything to give accurate information for heat loss caculations? Thanks again all.
  • Duncan_2
    Duncan_2 Member Posts: 174
    Stove island and bathroom

    ...Sounds like backdraft dampers on exhaust fans were either never installed, or not closing properly. Notorious leakers. Insulating those ducts could help, too. Maybe not eliminate the problem, but help.

    During my weatherization days, another problem area that kept showing up was cabinet soffits. That blank area above your kitchen cabinets and maybe bathroom cabinets? They were hardly ever insulated by average contractors in the days before energy-consciousness.

    Blower door is a top-notch tool for locating leaks. The ACH (air changes per hour) number can be used to do an more accurate heat loss. In my opinion, that's the biggest guess in doing a heat loss.
  • Dale
    Dale Member Posts: 1,317
    Known Air change

    is the method now - 2002 code -allowed in the National Fuel gas code to size combustion air openings. They knew that super tight houses may not have worked under the old "confined space 1/20 formula. With a wood burner the amount of combustion air is so high that they should have their own dedicated air supply.
  • Wayco Wayne
    Wayco Wayne Member Posts: 615
    Where does one buy

    a blower for these tests. Perhaps I should add it to my repitiore(sp?) of services. WW

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  • Greg_4
    Greg_4 Member Posts: 32

    Didn't mean to speak like a military guy with those acronyms they use. I'm a volunteer on the local fire dept. and we just purchased an I.R. camera this summer for rescue and initial attack team to search for hot spots. I've used the term I.R. so often it's like a normal part of speech any more!

    I won't even say what we charge for the blower door tests- as a utility, our headquarters feel we should provide this as a 'service' and charge very little. We're not competing with anyone, as ours is the only blower door or I.R. camera used for energy survey purposes within 100 miles. The marketing gurus are supposed to promote them, but really don't. But I do every chance and finally got permission to set up and perform them. I've offered to do them for competitors any time they want one for a nominal fee, but so far no takers.

    I like the I.R. simply because sometimes, what one would think is an energy problem in a home turns out to be the lessor of other evils. Some customers have had their contractor preview the tapes for guidance when doing energy upgrade work.

    Remember the Solar days? OK, I was just a highschool and college kid then, but the first thing a competent contractor was supposed to say is "don't go changing your energy source if you're not going to invest in weather-izing your home first!" This still holds true today, but now we know we can over do it and cause CO and other indoor air quality problems. That's where a blower door shines- another diagnostic tool. Greg
  • Greg_4
    Greg_4 Member Posts: 32
    One source is... Vary from +/- $1,800 to twice that. A manometer is needed to calc. air changes, duct losses, etc. I was told ours cost $2,300 but don't know what source or how old it is. There are other sources, but the usual HVAC sources such as Johnstone, JHLeavy, etc. do not carry them.
    The frame expands to fit most any residential personnel door, has a series of ports which can be opened depending upon how much air volume needs to be removed - eg. a 'tight' house doesn't need much air or time to evaluate air changes, older homes need a large opening for the fan to remove larger volumes. We were at a home/garden show with it set up and a contractor who builds ICF (insulating concrete form) dwellings walked by bragging "that thing would suck the windows out of one of my houses..." Too bad, talk about unleashing the homeowner with possible health, CO and other indoor air quality issues. Obviously builds in rural areas with no inspection. I'm sure he builds a quality product, but is unaware of problems he may be presenting the occupants with. We talked to him to no avail about IAQ. Greg
  • Dale
    Dale Member Posts: 1,317
    Blower Doors

    Pretty pricy blowers but they do work great and with the new NFPA 54 combustion air change they may become a more needed tool. The most popular model here is from Energy Conservatory in Minneapolis MN. I think. Phone 612-827-1117 Mechanicals are about $2000 with the software extra.
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