I think your PV system is oversized, unless you are drawing more load for power equipment or something else. I just finished a 2,000 sq/ft home using passive solar along with SIP's envelope and the heat losses are about the same. Just under 10 BTu's/sqft at design temp. I used a geothermal heat pump of the house and debate an air source. The pump we used was a 3ton, the smallest one that would heat and cool. For a home this efficient and loads so small, I would consider a Arcadia heat pump or a Mr slim, although I don't know the efficiency of the MR slim at Maine temps. The Acadia was designed in Bangor to handle the tough Maine winters and claims a COP of 3. Use this with a split ducts system and it could provide heating and cooling to both buildings. The 2,000 sq/ft home I built used about 1,000 Kwhrs of electricity for the months of Feb and March this year. Total electric house that will have a solar hot water system up later this spring but for now is running on electric as well. Conduit has been run for the PV to be added later, local electrical company is putting regulations in place right now for net metering. Designed to go to zero once the cost makes sense, still a 20year payback at current energy rates.
       If you are looking for something that will provide the heat needed without electricity propane make sense. The Jotul stove looks nice and will provide all the heat needed consider the smaller one with the one the Max output of 17,000 Btu's. Still bigger than needed but more likely to save energy while still meeting your demands. Matching a heating systems output to the demand is one of the ways to get the most efficiency of the system. Sometimes when systems run at loads less than spec'd they tend not to run as efficiently. If the stove is to large you will heat up the space before the stove comes up to the minimum temp needed to run efficiently, creating on off cycles that waste energy. Keep the supply system as close to the demand with a small safety factor for the days when the temps drop below design temps. Not an everyday occurance but it the temps go down to -40 and the system was designed for -10 or -20 you may find yourself a little cold. Especially up in Maine, what part of Maine?

Good luck, the project looks great and it is always encouraging to see others that want to build zero energy homes.

Here is something you don't see everyday and is the first of it's kind. A thermal mass window system designed to capture and store the suns energy in the windows. I didn't get the heat up and running in this house until mid Feb and the house went through some pretty cold weather, at least for southern New England. These windows only went down to 49F on the coldest night -8F and the house dropped to 42F at this time. No other heat and once the sun came back out the temps went back into the mid 50's inside. This was the extreme after a week of highs in the teens and lows below zero the windows maintanined temps above freezing. Check it out.

http://www.youtube.com/watch?v=qdUGDAqyagU&feature=channel_page
 
Tom Pittlsey
ecobuilder@aol.com
www.eebt.org

Hi, John. I just joined this forum today, so I missed out on your earlier discussion. If you have not committed to a pellet stove, you might want to look at the Woodstock line of gas stoves. Those of us who heat primarily with wood swear by their soapstone stoves, and now they make propane ones, also, including a very small one which might work for you: http://www.woodstove.com/pages/gas_stoves.html

Woodstock does not sell through dealers, but only direct through the factory in Lebanon, New Hampshire. They will ship via motor freight to a loading dock near you, but it's great fun to visit the factory and pick out your own stove.

Regards,

Herb