[Greenbuilding] Passive House, WAS why do houses have to have stay the same tempinside?
Corwyn
corwyn at midcoast.com
Sun Aug 19 11:31:51 CDT 2012
On 8/19/2012 7:28 AM, Gennaro Brooks-Church - Eco Brooklyn wrote:
> I love Passive House but the one big issue I have with it is that you
> are putting all your eggs in one basket. Once you do an air pressure
> test and try to find the leaks you realize how a simple tiny hole
> drastically changes the pressure of the building. Yet all the
> calculations - heating, insulation, cooling etc - are based on there
> not being any holes.
This is quite simply not true. PH has a lower limit for amount of holes
(ACH50 of 0.6). If you want some leeway, you can reduce the leakage to
below this number. No house is without any holes.
> This means that some time in the future WHEN the
> building gets a hole (because it will) all of a sudden your heating
> and cooling systems are completely inadequate.
Sadly, most Passivhaus buildings are unable to find heating and cooling
systems *small enough*. So there is usually far more unneeded heating
and cooling capacity than in a comparable leaky building.
> And good luck finding that hole.
You find it, the same way you found it during construction with a blower
door.
Frankly, building a crappy house, *because* a well-built house might
someday become a bit worse (and lose say 20% of the heat of the crappy
house instead of 10%) is lunacy.
Thank You Kindly,
Corwyn
--
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.greenfret.com/
topher at greenfret.com
(207) 882-7652
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