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Dodd Stacy


In doing cursory research for our PV system, I came across a PEF of more like 0.1, vs the Passivhaus Institute value of 0.7. I could possibly resurrect the source. Can you cite the German source?


I get this value at page 166 of the Passive House Planning Package 2007 Manual, which lists the PE factors to use in the Primary Energy worksheet in PHPP. One of the four PH criteria is that total PE does not exceed 120 kWh/sm/year (note that PHI calculates floor area according to a German standard that does not include stairs, walls, etc., and therefore the area is often 75-80 percent of the gross floor area - making all three area-based criteria harder).

In no way do I endorse the 0.7 PE factor, but I'm ignorant to say what the correct value is. It's not zero and it better not be one, but I don't what it is.

Small Water Pump

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Bruce Harley

Really useful stuff. So, unless I missed it, I don't think you said how you're getting domestic hot water now. I'm very curious, because this is a non-trivial end use that was clearly included in the daily oil consumption of the Buderus. I haven't seen you account for hot water use in the present situation. If I missed the discussion, which is entirely possible, just point me to the right spot.

Marc Rosenbaum

I threw a 10 gallon electric water heater in as a stopgap for a few weeks. I'll get to the DHW soon!

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Tad Montgomery

The heat pump option improves from a climate standpoint inversely proportional to how much fossil fuel is in one's utility's mix. Here in VT, with VT Yankee and Hydro Quebec being our major sources, the heat pump option looks quite good, at least from a climate standpoint and if our lower winter temperatures don't drain too much efficiency.

The peak oil folks say that the average EROEI (Energy Returned On Energy Invested) for liquid fossil fuels is down to around 7. If I convert this to your PE figure it looks to be 1.125, which is pretty close to your 1.1.

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