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Green Building Bible, Fourth Edition
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    I'm about to have a 3rd blower-door test performed on my house. The first one was in 2004, prior to any renovations and came in at 12.5ACH@50Pa. The next one, in early 2006 (but before all the renovations were completed) came in at 6.4ACH@50Pa.

    Now I'm leading a local "EcoAction" project for our community and have teamed up with an energy auditor. He has eight sets of blower door test equipment and said he'd train me and the students working on the project how to perform the tests. So we're going to re-test my house next week. I'm guessing it will come in at about 4ACH@50Pa now (having had old leaky skylights replaced). We'll then enter the new data in hot2000 and see how it compares with my measured energy consumption over the last year or so (though I have weekly meter readings going back to August 2005).

    Part of the EcoAction project is to measure the baseline consumption of typical properties in the community and then re-assess after any improvements are done. Air leakage reduction is one of the best measures in terms of ROI that can be performed, but measurements have to be taken. So we're going to be offering free blower door tests to people who want to participate. Should be interesting!

    Paul in Montreal.
    Will you travel? :wink:
    Posted By: Nick ParsonsWill you travel?

    I could be persuaded, not sure the equipment will fit into carry-on luggage though!

    The good news is that there are various energy audit programs here that charge only $150 for an energy assessment (which includes blower door test). If you do a 2nd test post-renovation, you get $100 of the $150 back, plus whatever grant based on the level of improvement. The only problem is that very very few people have taken advantage of this program.

    I'm working with local community groups and the Urban Planning department at McGill University to try and create awareness in the community and bootstrap people into making energy efficiency improvements. Part of this project involves measurement, hence the blower door testing as reducing air leakage in old houses can have huge paybacks, both in terms of reduced energy usage but as well as improved interior comfort in winter due to raised RH levels (quite the opposite problem of the UK I think).

    Paul in Montreal.
    That sounds brilliant. I hope you manage to get more take-up.
    • CommentTimeApr 18th 2013
    Posted By: Paul in MontrealPart of the EcoAction project is to measure the baseline consumption of typical properties in the community and then re-assess after any improvements are done
    About time it was done properly, well done.
    Any chance of you hopping on a flight to Copenhagen Paul?

    Just got a quote for a blower door test here in Sweden, an eye watering £645!

    I'm really conflicted as whether to get it done at that price.

    I'm not going for certification so it's not absolutely necessary on that front but at the same time I'd like to have confirmation that I haven't left a gaping hole somewhere particularly in the bottom corners of the roof where there are multiple folds of membrane to deal with and a error could be made.

    I will have to take a look at the bank balance over the weekend and see if the expense can be justified.
    Posted By: Chris P BaconAny chance of you hopping on a flight to Copenhagen Paul?

    I'd love to - the cost you were quoted would pretty much pay for the flight, though I might have to pay baggage fees. Maybe I could become an itinerant blower-door tester! The system I'll be using is supposedly very fast to setup/tear down so I'm looking forward to trying it out on Wednesday, and am anxious to see if the result is anywhere near what I've predicted. If so, it will be pretty good for a 115 year old house!

    Paul in Montreal.
    • CommentAuthorTimSmall
    • CommentTimeApr 19th 2013
    Posted By: Chris P BaconI'd like to have confirmation that I haven't left a gaping hole somewhere particularly in the bottom corners of the roof where there are multiple folds of membrane to deal with and a error could be made

    If you haven't already, then I'd recommend taking a look at the DIY leak testing thread.

    Reasonable car rad fan - ebay £10.
    Old PC power supply, or battery charger to power it - £15.
    Disco smoke machine - £45.
    Hand help smoke machine - £30.
    Bit of plywood etc. to stick it in a door / window - £10.

    Total: £110

    If you want to get some actual hard figures out (instead of just test using it for leak detection) then add:

    Bit of tube to stick on the back of the fan £10.
    Hand-held anemometer £40.
    Plastic tube + food dye for manometer £5.

    extras: £55

    I can really recommend it - will be doing some more leak testing on my place on Monday - you don't have to fit in with someone else's schedule either.

    Thanks Tim I might just resort to the DIY method if I can't get a more competitive quote.

    After doing a bit of Googling I found another guy closer to me but he has just replied with a quote of approx. £690 + £60 an hour if it goes over 4 hours!
    • CommentTimeApr 19th 2013
    Take lots of pictures, even of the manual and part numbers, then we may be able to copy the kit.
    The UK building regs default value for air permeability testing is 10 m3/m2/hr - ie for a 100m2 house, you would be allowed 1000m3 of air to enter the house at 50Pa pressure. To make your own you need a manometer to measure the air flow, and 1000m3/hr is a lot of air - a bit much for a radiator car fan.
    • CommentTimeApr 21st 2013 edited
    Posted By: brazenscroll1000m3/hr is a lot of air
    1/3 kg a second or 0.28 m^3.s^-1. I would have though a large car fan would do that. 2 certainly would.
    • CommentAuthorTimSmall
    • CommentTimeApr 21st 2013 edited
    Posted By: brazenscrollUK building regs default [10 Ach - ] 1000m3/hr is a lot of air

    Yeah, but hopefully his house won't be anywhere near that pants! :bigsmile:

    He'll need a manometer to set the fan speed until it's roughly 50 pa differential between inside and out (or maybe obscure the fan to if you can't arrange to vary the speed - If you use the PC power supply option, then you can choose 5v, 7v, or 12v to power the fan - hopefully one of those will be close enough). He'll then need an anemometer to measure air flow (a piece of duct/pipe upstream of the fan is needed - the cross-sectional area of the duct will give an area, multiply by the air speed to obtain volume flow).

    Alternatively dispense with all the measurements, and just use the fans (plus smoke machines) to find leaks, then plug them.

    • CommentAuthortony
    • CommentTimeApr 21st 2013
    I think that you will be surprised at how much fan power is needed to get your house up to 50Pa
    • CommentAuthorTimSmall
    • CommentTimeApr 21st 2013 edited
    The amount of power needed to reach 50 Pascals all depends on how leaky the house is surely? RobL was getting up to 90 Pa with his car rad fan...


    The fans that I'm using will pump out a bit more than 5000 m³ per hour at 50 Pa when running at full power (it's not a car fan, but it is a similar shaped 400mm diameter axial fan). I did a quick Google for car radiator fan curves, and the first one I found does about 2800 m³ / hr at 50 Pa.

    After some searching and negotiating I finally found a guy to do my blower door test for a slightly more reasonable £390.

    The test was done this morning and I am delighted to be able to say that the house met Passive house certification criteria for airtightness with an average result of 0.40ACH @ 50 Pa, 0.36 on pressurisation and 0.44 on de-pressurisation.

    As you can see in the photo as the house was so tight we didn't need much of a fan opening.
    Still haven't had mine done - the tester was called away and then I was away for work ... hopefully will get it done in the next couple of weeks.

    I'll try and take lots of photos as supposedly he has a special method to make the testing much faster than normal. As far as I know, though, over here, only depressurization testing is done.

    Paul in Montreal.
    Posted By: Paul in Montreal over here, only depressurization testing is done.

    Someone more knowledgeable than I can say for sure, but my understanding is that the de-pressurisation test is the most important in than it best represents windy conditions which is most likely going to cause heat loss but the pressurisation test is also important as it shows up any deficiencies with the seals of outward opening windows and doors (we have both).

    As for the speed of testing that was all down to the software which controlled the fan and ramped up the pressure from 20 Pa to 90 Pa- Other than adjusting the parameter for the speed at which the fan steps up the building pressure there is no operator influence on the speed of completing the test.
    • CommentAuthortony
    • CommentTimeMay 3rd 2013
    Ther may have been an operator choice of aperture sizes for the man, my tester has to use his smallest aperture ring.
    Finally had my blower door test done today. We had two students helping, a Master's in Urban Planning and an undergrad in the same department. So all the testing was done manually, without computer control of the equipment - due to this, I won't have the results for a couple of days.

    In the meantime, here's a couple of photos setting up. As I'm still renovating my vestibule, we installed the blower unit in the inner door - but later we put it in the outer door to compare and, to my surprise, the readings were lower.

    Paul in Montreal
    Well the results weren't as good as I thought - seems I'm at about 6.15ACH@50Pa - though I do have a missing ceiling and front interior wall in my vestibule. I have access to the test equipment for another few weeks so I'll see if I can get those parts finished and re-test. There's a considerable amount of air that comes through the solid triple-brick wall between me and my neighbour - this was quite the surprise!

    Paul in Montreal.
    That's disappointing for you that you are not seeing a better result for the work you have done since the last test.

    Presumably the improvements are being by-passed by a larger air loss somewhere else? Possibly the loss through the party wall?

    At least in that case if your neighbour's house is heated similar to yours even if there is air movement between the two you won't have any heat loss because of it. The only concern would be if the wall is that porous you may have heat loss by it into the attic or crawl space.

    The only thing I can think of is to pressurise both houses simultaneously to hopefully eliminate that air loss from your test.

    But it sounds like thermal imaging is your best bet for identifying areas for future improvement.
    Posted By: Chris P BaconBut it sounds like thermal imaging is your best bet for identifying areas for future improvement.

    True. All said, though, I've reduced my energy costs by about 80% compared to the "old" house. I don't think there's much improvement to have.

    Posted By: Chris P BaconPresumably the improvements are being by-passed by a larger air loss somewhere else? Possibly the loss through the party wall?

    I think it's the fact that I have the ceiling and wall open in the vestibule that is making the leakage appear worse. I'll try and get that completed in the next few weeks whilst I have access to the blower door equipment. I know that replacing the skylights and front door just over 18 months ago reduced the subsequent winter's heating bill (normalizing for HDD differences) by about 5%

    As for the party wall issue, it's a solid triple brick wall and the neighbour's house is heated, so I'm not too concerned. I don't think there's any link into the attic as that wall becomes the outside wall of the neighbour's hosue (they have one more story than me). It was interesting to see that even solid brick walls are not airtight!

    Paul in Montreal.
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