Christian Nelson,
Just a quick reply, I'm getting ready to leave town for a few days, so my time is short...
Wow! Sounds like you're really taking the bull by the horns! Yeah, I think you're on the right track with the insulation. I like the idea of zero infiltration. At some point you may need to consider a heat recovery ventilator, if your house gets super tight.
Regarding heat pumps, the reason I got into building mine is that I couldn't find a water-in-water-out unit that was less than 4 Tons (1 Ton = 12,000 BTU/hr). It looks like your weather conditions are quite demanding, compared to mine and your house is larger too, so you may be able to find a unit already built that would work for you, in the 4 Ton range or larger.
Don't know if you read the part of my blog where I talked about using electric heaters with Kill-A-Watts attached to get precise real-time heat loss measurements. Don't know if I'd try that on a house as large as yours, but if you could measure the amount of propane you actually use an a per hour basis, as temperature fluctuates,it would be very useful information for future heating calculations.
I found that the Hydronics Explorer program over-estimated my heat requirements by about 50%, which is really quite close.
So, if you are able to keep your house warm with feed temperatures of 120 or less, you'd be a good candidate for a ground source heat pump, because that's pretty close to the limit of the present technology. The Japanese are working on Carbon Dioxide vapor-compression units which will reach higher temps. Some units are entering the market already.
So the feed temperature is important. Better insulation means lower feed temperatures, less firewood, less propane, less Tons of HVAC, as I'm sure you know already.
I think your wife deserves a shiny golden trophy... not every wife would survive such a major upgrade adventure such as your family is on.
Kudos to all of you!
Best regards,
-AC_Hacker
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