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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorjwd
    • CommentTimeJun 20th 2016
     
    I have recently heard rumours that there are emerging health issues with passive houses in Germany. I m having difficulty finding any details on this and was wondering if anyone could shed any light.
    My understanding was that a well designed mhvr system would result in better air quality but I may be wrong. Are some construction materials (treated timber, foam insulation) implicated or are these cases emerging from all construction types? Any thoughts?

    Cheers.
  1.  
    jwd,
    I have always been skecptial re the health implications of "air-tight" houses, especially the reliance on changing roofspace mounted 'orribly dirty air filters.
    I will live in a slightly cooler naturally ventilated home until I die.
    Simples
    • CommentAuthorgravelld
    • CommentTimeJun 20th 2016
     
    "Rumours" are not good enough to base a discussion or debate on.
    • CommentAuthorCWatters
    • CommentTimeJun 20th 2016
     
    Some discussion and controversial comments here..
    https://sourceable.net/passive-houses-cause-health-problems/

    For example..

    The investigator, Dr. Hugo Hens, a professor in the Building Physics unit of the Department of Civil Engineering at the University of Leuven in Belgium, drew some conclusions in his paper, Passive Houses: What May Happen When Energy Efficiency Becomes the Only Paradigm

    “Though solely promoted as energy savers, their impact on energy consumed is too minimal [for] the possible risk they create in terms of degrading supply air quality,” he remarked.
    • CommentAuthorgravelld
    • CommentTimeJun 20th 2016
     
    Evidence based on a click-bait straw man hypothesis is also not good enough.
    •  
      CommentAuthorfostertom
    • CommentTimeJun 20th 2016
     
    What does he mean by
    Posted By: CWattersthe possible risk they create in terms of degrading supply air quality
    Is it just the risk of not cleaning filters?
    • CommentAuthortony
    • CommentTimeJun 20th 2016
     
    The greater risk is of breathing unfiltered air!!
    • CommentAuthorEd Davies
    • CommentTimeJun 20th 2016
     
    Posted By: gravelld"Rumours" are not good enough to base a discussion or debate on.
    True. Makes the OP's question:

    Posted By: jwdI m having difficulty finding any details on this and was wondering if anyone could shed any light.
    seem quite reasonable.
    • CommentAuthortony
    • CommentTimeJun 20th 2016
     
    If there were problems then they would be easy to find information about it.

    No information means no problems
    • CommentAuthorringi
    • CommentTimeJun 20th 2016
     
    Posted By: tonyIf there were problems then they would be easy to find information about it.

    No information means no problems


    Not true, if the risk was say 5% increase in X, it would not show up on most stats as there are not enough passive houses and medical researchers are unlikely to include "lived in a passive home" in their datasets.

    I also question if a baby spends most of their time in a passive home, will there be issues with the air being to clean, leading to immune system problems...

    But given the option I would choose to live in a passive home!
    • CommentAuthorMarkyP
    • CommentTimeJun 20th 2016 edited
     
    I remember a rental house, when I was a strudent, lovely spot overlooking the north circular road near Brent Cross in London, the net curtains were our air filter and were filthy black. I remember we washed one to see how long it took to go black with soot again, it was only a matter of weeks.
    • CommentAuthorMarkyP
    • CommentTimeJun 20th 2016
     
    I dont know much about passive houses, I've seen lots about the air tightness tests, but is there any scope for an air quality test? All that effort in air tightness, ducting, filtering - I'd be inclined to want to know that it was worth the effort and giving me an indoor air quality that was better than opening a window.
    • CommentAuthorringi
    • CommentTimeJun 20th 2016
     
    Posted By: MarkyPI dont know much about passive houses, I've seen lots about the air tightness tests, but is there any scope for an air quality test? All that effort in air tightness, ducting, filtering - I'd be inclined to want to know that it was worth the effort and giving me an indoor air quality that was better than opening a window.


    Define "air quality", then consider the air quality on the space station compared to in the open on earth, and then consider what Tim Peake said about the air....
  2.  
    I suspect that there is a potential problem out there. We all know that one of the issues with air tight and well insulated houses can be high humidity and mould. PH's overcome this by having MHRV, but that does require regular cleaning/checking etc. of the filters in the system. Early adopters will have been up to speed with this, but more "normal" people may not be, and aren't doing it. I don't like to to think too hard about the problems caused by blocked fiters & contaminated ducts.
    It is one of the truisms that joe ordinary expectes everything to work FOR EVER with no TLC.
    • CommentAuthorringi
    • CommentTimeJun 20th 2016
     
    Even buying a filter is hard as B&Q does not stock them!
    • CommentAuthorCWatters
    • CommentTimeJun 20th 2016
     
    My system has a very crude filter - just a lump of foam with quite large pores. It only really keeps the larger bugs out. It still gets blocked in about 6 months. Fortunately you can just wash it out.
    • CommentAuthorborpin
    • CommentTimeJun 20th 2016
     
    Had BC round for his final look on Friday. The discussion of the MVHR unit ensued. He told me that the regs (Scottish) from last October required the installation of a CO2 (not CO) meter in all homes. He also said it was noticeable that houses he visited with HRV had far better air quality than those without.
    • CommentAuthorEd Davies
    • CommentTimeJun 20th 2016 edited
     
    Posted By: borpinHe told me that the regs (Scottish) from last October required the installation of a CO2 (not CO) meter in all homes.
    I think he's wrong. There was a new requirement for CO (monoxide) detectors in rented accommodation with fixed combustion appliances, which came in on December 1st last year, which is probably the source of the confusion.

    I think he's right. Looking at the Domestic Technical Handbook for 2016 it says:

    CO₂ monitoring equipment should be provided in the apartment expected to be the main or principal bedroom in a dwelling where infiltrating air rates are less than 15m³ /hr/ m² @ 50 Pa.
    There's a lot more on it being mains powered, etc, and being able to log for at least 24 hours. Wow.
  3.  
    I wonder...so the 2 couples go out for dinner and some beers and end up back in the same large bed in a rather small room, you know - 'up for some fun', but as there is a kid sleeping down the corridor, they shut the bedroom door; drunk and after some hard exercise they all fall asleep. Unbeknown to them the kid turned off the MVHR when it kept boosting due to a cold front bringing in really humid air at the end of a dry summer, anyway the 4 died: asphyxiated. ?
  4.  
    Any where there is human interaction required there is the possibility of failure. So I am sure there is a percentage of people who do not renew filters according to plan or do so incorrectly. The father in law, being the skin flint that he is, vacuum cleans his MVHR filters twice before replacing to extend their life. Not sure what impact that has on air quality?
    • CommentAuthorjfb
    • CommentTimeJun 21st 2016
     
    I think vacuum cleaning and washing the filters is entirely sensible. At least I was told so by the company where I got the Mvhr unit! (And in the manual too ) Maybe it depends on different filters but I doubt it.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 21st 2016
     
    I can't see that there is any greater risk to health with a PassivHaus compared to any other new house.
    Not as if they are built with anything novel and untested (uranium walls or radon filled heat pumps).

    I used to be the production engineer for an air filtration company. There was nothing special about our filters, could stick them in a washing machine. Most where reticulated foam and the only ones that were very fine where for special applications. The mining and car ones where pretty course and trapped most of the dirt. Thickness is as important as poor size.
    You can easily make up your own filters with ScotchBrite type scourers, the foam is similar. They also work well as fish tank filters.
    • CommentAuthorgravelld
    • CommentTimeJun 21st 2016
     
    Posted By: GotanewlifeI wonder...so the 2 couples go out for dinner and some beers and end up back in the same large bed in a rather small room, you know - 'up for some fun', but as there is a kid sleeping down the corridor, they shut the bedroom door; drunk and after some hard exercise they all fall asleep. Unbeknown to them the kid turned off the MVHR when it kept boosting due to a cold front bringing in really humid air at the end of a dry summer, anyway the 4 died: asphyxiated. ?
    I think we did the sums on this before and ISTR it would take a lot longer than that to reach dangerous levels... 2 weeks, given assumptions, IIRC.
    •  
      CommentAuthordjh
    • CommentTimeJun 21st 2016
     
    The basic filters (G3/G4) used with MVHR to protect the heat exchanger and filter most things from the external air are usually foam pads in a frame or pads fixed to a frame. Most of them can be vacuumed or washed as often as you like until they sustain too much damage, though I believe those for some MVHR units are designed so you can't. Pollen filters (F6/F7) are both more expensive and more delicate.

    My MVHR has a red light that comes on in the speed control that is in our hall when the filters need cleaning (I think it decides based on how hard the fans are having to work).

    Interesting about the CO2 monitors in Scottish regs. I see they need a display and a logging facility but they do not need an alarm! So I guess there's no concern amongst Scottish experts about possible asphyxiation. Which would also be my view. Background CO2 is 400 ppm, normal internal is up to 800 ppm, start of staleness about 1,200 ppm, toxicity apparently around 100,000 ppm.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 21st 2016
     
    Be interesting to see if the price of CO2 sensors come down.
    • CommentAuthorgravelld
    • CommentTimeJun 21st 2016
     
    There's a device called uHoo that is in development, it was featured on Home Style Green a few weeks ago.
    • CommentAuthordickster
    • CommentTimeJun 21st 2016
     
    We had to install MVHR for the mortgage. Never used it, leave a couple of windows on the click whatever the weather and it maybe costs us an extra log or two per day in the winter. Monitored CO2, fine and dandy. No condensation/mould problems.
    • CommentAuthorsnyggapa
    • CommentTimeJun 21st 2016
     
    I have washed our vent axia filters every quarter for about 4 years. Recommended by the man who came to fix it - don't replace, wash in warm soapy water, rinse, leave out to dry. Replace when visibly knackered

    they collect a lot of filth in 3 months, mostly very fine dust that turns a bowl of water into a kind of black soup, so they still work to some extent :)
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 21st 2016
     
    Posted By: gravellduHoo
    $299, and they have not delivered any

    https://uhooair.com/

    I wonder if it also logs the data.
    • CommentAuthorMike1
    • CommentTimeJun 22nd 2016
     
    jwd

    The best report that I've come across is An investigation into recent proposals for a revised definition of zero carbon homes in the UK, published in Energy Policy Volume 46, July 2012, Pages 25–35. Fortunately you can download a PDF of the article from http://eprints.brighton.ac.uk/14958/1/InvestigationRevisedDefinitionZeroCarbonUK_120227_RM_(Converis).pdf

    Section 6.2 focuses on indoor air quality, and suggests that there is not a great deal of concern - though, as mentioned above, the need for ongoing maintenance is critical.
   
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