[Greenbuilding] Aggressively Passive: Building Homes to thePassive House Standard

[John Straube]

No, Bob, PH is both smarter and dumber than that.
The energy metric is based on source energy: that is energy that feeds an electric plant, or the gas used to transport and compress natural gas.
So if you house was all electric, it would be limited to 42 kWh/m2/yr because the electricity grid in Germany requires 2.7 units of energy for every unit of electricity (this is 3.35 in the United States, but the PHIUS uses the ratio for the German power grid: no I am not making this up).
This is what PH uses, as does the Department of Energy.
The other thing is that your 1500 square foot house, would not be 139 square meters, as you need to subtract walls and stairwells and a few other things. So your house would become 105 or 110 m2.  Yeah, I know, odd.
Net effect is you would be allowed to use 4000-4500 kWh/yr if an all-electric house.  This  could be 2500 kWh/yr of electricity and 5000 kWh/yr of natural gas energy (170 therms).  You can use passive solar and active heating or air/water, but not active generation of electricity.
For a family of four, 2000 kWh of electricity and 170 therms of gas is no mean feat.

The easy way to meet the 120 kWh/m2/yr source energy is to build a larger house.  If you house was say 4000 sq ft (about 3000 sq ft measured by PH) you could use 6000 kWh of electricity and 680 therm of gas, which is about half (50%) the energy the average current house uses in the US, and about 30% less than a new code built home of your size.



On 2011-01-09, at 5:47 PM, Bob Waldrop wrote:

> ----- Original Message ----- From: John Straube
> >area based energy metric (120 kWh/m2/yr)
> 
> This is the standard for the passive haus?  Hmmm, for a 1500 sq ft house (1500/10.76 = 139.4 sq meters, times 120 = 16,728 kwh/yr, we do better than that with our amateur redneck extreme green  house.
> 
> Bob Waldrop, OKC 
> 
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org

Dr John Straube, P.Eng.
Associate Professor
University of Waterloo
Dept of Civil Eng. & School of Architecture
www.buildingscience.com