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Data and monitoring: Is there any point in a blower door test?

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  1.  
    • CommentAuthorpmagowan
    • CommentTimeMar 18th 2011
     
    Is there a point in doing a test before my renovation? I am thinking I could spend the money elsewhere. It would be nice to have a before and after but I don't think a blower door could get my house up to pressure at all. Should I just assume the worst possible starting point? I will get one as soon as the air-tight part is completed so that I can patch where needed to achieve MVHR syandards. Are there any monitoring methods that people would recommend to, cheaply, estimate the effect of renovation? Should I just count up my energy usage over the last few years and compare?

    The context is a large detached house with no insulation and solid walls. Plans are 200mm eps EWI and similar above rafter. Website (only draft version): http://web.me.com/pmagowan/Site
    • CommentAuthorwookey
    • CommentTimeMar 18th 2011
     
    Exactly. It 'would be nice', but whether it's worth spending 200-quid (at least) on, is up to you. I decided not to bother.

    Various home-made bodge schemes (e.g. with car radiator fan and a manometer) could be conjured up which would provide some kind of relative measure of change if you were so inclined.

    Careful energy-usgage records for before and after are clearly useful, but of course lump together all simultaneous changes (heating system, airtightness, insulation, behavioural change).
  3.  
    Apart from certification, a blower test's main use is to tell you where the leaks are so you can fix them. You already know there are areas that need improvement, and these probably dwarf the losses from the places you don't know about. As such, it's unlikely you'll learn very much from a blower test at this stage. It will help you quantify what level of improvement you have made, so contribute to a "feel-good" factor. Overall, I wouldn't bother.

    The only possible point is whether there is a risk of a significant air leakage that you don't know about but that will be very hard to rectify after you have started on the renovation. I can't immediately think of any obvious examples.

    I'd focus on a test after you've done the bulk of the airtightness improvements that you already know about. That will be much more useful.
    • CommentAuthorpmagowan
    • CommentTimeMar 18th 2011
     
    Thanks guys. Thats what I thought. My house is so leaky i've been thinking about installing a wind turbine in the bedroom! I will save my money for the second stage. No matter what I do it will be an improvement

    Paddy
    • CommentAuthorbuckyp
    • CommentTimeMar 18th 2011
     
    Doing an air tightness test and including thermal imaging at the same time will really show you where you have issues and help you to put together a plan to target these areas. You could spend a lot of money and not achieve your potential, by spending money on identifying the areas that lose heat and allow draughts you could potentially spend a little less by putting your money where it is actually needed and achieve maximum benefit!

    www.sustainablelifestyles.co.uk

    Paul.
    • CommentAuthorpmagowan
    • CommentTimeMar 18th 2011
     
    Thanks Paul.
    I am covering the house in an air tight seal and 200 mm of EPS on walls and roof. I am sealing all windows and moving then into the EPS zone. I am removing any unused chimneys. I will be putting in the EWI/Lecca wing foundation.
    I can't think of any areas that I could focus more on. The house should be reasonably uniformly insulated. I would love to have the thermal imaging etc but tricky to get in NI and I am sure it will probably tell me what I already know.

    If you see my website ( http://web.me.com/pmagowan/Site ) you can see I am being careful re thermal bridging in essentially removing all but completely unavoidable ones. Do you think a TI test would be useful when so much is going to be altered?
    • CommentAuthorseascape
    • CommentTimeMar 18th 2011
     
    My house is stone built, with crittell windows, badly fitting doors and an uninsulated wooden floor with big void underneath and gaps between ceiling and roof space and a gale runs through it, so I understand turbine scenario! If I owned it I would only do test after I'd fixed these, to fine tune.

    Incidentally I've stopped using my storage heater except during Christmas freeze by cling filming some of the windows and putting length of foil insulation (!) that I found had under vinyl strip on kitchen floor and hanging thick wool blankets over worst of the doors - makes a huge difference. Turned Rayburn down to 1 and stopped using dishwasher cos I have hot water anyway. Aiming to turn Rayburn off end March i/o end April. Money saved going towards new build insulation/pv.
    • CommentAuthorpmagowan
    • CommentTimeMar 18th 2011
     
    Sounds good Seascape, I too have discovered the benefits of cling film. In fact one of my plans for the renovation is to develop a cling fiml double glazing unit to add to my windows making them triple glazed! I will try and report back any improvements this makes. I turned the Aga off altogether as there seemed little point in it. I got myself a Tom Good style wooly jumper instead. One of the problems is that unless this renovation comes soon it will make sense to install small scale hydro in the stairwell due to the water running down the walls when it rains!
    In my opinion doing a thermal analysis of my house prior to work would be of similar effect to doing the same in a new-build! There may be many things that I am missing though!

    Paddy
    • CommentAuthorbuckyp
    • CommentTimeMar 18th 2011
     
    I think sealing all the gaps and draughts first before EWI would be beneficial because EWI on its own will not really make the house airtight, TI would show you where the leaks are from the outset. I'm maybe a bit biased because I do thermal imaging but I have found so many issues with buildings even after a certain amount of refurbishment (not to the extent that you are going to) that I would recommend a survey before so that these issues can be addressed during the refurb rather than trying to sort them out after.

    Paul.
    • CommentAuthorTimber
    • CommentTimeMar 18th 2011
     
    It would be a 'nice' thing to have done, just to highlight any unknown issues, although it sounds like your plan will sort any unknown issues by default.

    You can get a test for as little as £200, so not a huge expense, and believe me they should be able to get it up to pressure.
    • CommentAuthorseascape
    • CommentTimeMar 18th 2011
     
    pmagowan - changed my mind after looking at your website - amazing house - big project. It maybe good to do tests before (even if house does defeat the technology) and after and post on website, and remind yourself down the line why you started.

    Recommend sheepskin for superior warmth unless you are vegetarian. Have no helpful suggestions for water pouring down walls - at least you've got good ventilation...
    • CommentAuthorpmagowan
    • CommentTimeMar 19th 2011
     
    Thanks guys,
    Tha plan is a parge coat of adhesive prior to EWI, paul, so that should seek most gaps. The air tight membrane on the roof will be continuous, as my eave detail removes any breaks, and will join to the parge coat. Then it is windows and doors which I can seal individually.
    Timber, I was thinking it might be like trying to blow up a burst balloon. Also slightly worried the windows would pop out under pressure!
    Thanks Seascape, it is a crazy house but I like to keep busy. Maybe I should speak to a tester and see if they do discount for before and after.
    I like science and would like to be able to do nice experiments to see the effect of my work. The problem is so much is changing and I have no controls. Probably, at the end of the day, I will just be able to report back subjectively that it is much nicer to live in!
    Thanks
    Paddy
  13.  
    Posted By: pmagowanAlso slightly worried the windows would pop out under pressure!
    The 50Pa normally used in a blower door test is equivalent to a 20km/h wind across your house (something like that) - it's a really small pressure and your windows will not pop out (or in if it's a depressurization test - which is better for spotting leaks).

    Paul in Montreal.
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 20th 2011
     
    In case it is any use to you, here is me experience of having two tests done one my house (to see how consistent they were):

    http://www.earth.org.uk/testing-a-house-for-air-leaks.html

    And no, the windows don't pop out (or in), and even small children playing the house were not bothered!

    Rgds

    Damon
    • CommentAuthorTriassic
    • CommentTimeMay 11th 2011
     
    This may be of interest to some - A practical guide to building airtight dwellings - sorry about the long link

    http://docs.google.com/viewer?a=v&q=cache:99FwEWGMpO4J:www.nhbcfoundation.org/LinkClick.aspx%3Ffileticket%3DId3W%252BcSdRak%253D%26tabid%3D339%26mid%3D774%26language%3Den-GB+bre+airtightness&hl=en&gl=uk&pid=bl&srcid=ADGEESi0bWfjn1_ob-Wp2V9-kdhoPzPnW5pVy-8hAYc2y1QRaJ3QZJ39_b8JKs7ChDfKdCFtY362YZUloD7pHyFUAIRjixYcizHR6h2Dcpk6YOGkWPOmAE4KOWdIPr15uzYNdeMqeBiq&sig=AHIEtbQg6VeGDjOHBeajtJifkZ5mNEIOXw

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