Regarding the air source heat pumps, there is another all climate heat pump made by Mitsubishi that you may want to consider. It’s called the Zuba Central:

http://www.mitsubishielectric......re_ENG.pdf

claims to be efficient down to -30C outdoor ambient temp with a COP range of 1.4 to 3.19. 15 seer cooling and 9.4 HSPF heating. if it works as advertised should outperform gas furnaces with added bonus of providing cooling and heating all-in-one.

there was that other all climate heat pump by hallowell, but i figure with mitsubishi you get a more established name and i’ve read great things about their mr. slim ductless split systems.

He did suggest that we could get away with a “lesser” system, but I’m interested in the “whole package” management that the Infinity system provides. It’ll obviously cost a little more, but I think the overall comfort of the home will be that much better because of it.

As for the roof values, they are indeed correct. We had originally thought about going above code (which is R-38 here as well), and come to think of it… we might actually up that a bit. We haven’t made the final decisions on that (and thanks for pointing it out!)

If your mechanical engineer hasn’t already mentioned it, running one of the more extensive calcs like “Manual J” would be good for properly sizing you equipment. With those great R-values, you should be able to significantly reduce what would typically be installed in a house of this size.

Actually, are you sure the roof value is correct? Most of your heat wants to get out at the roof – local codes in the states want an R-38 minimum…

When we built our home, it was suggested we get a two zone system. We decided the price was too great. I am glad we did not do it as the basement is the warmest part of our home (around 2000 square foot bungalow). We have finished the basement and insulated the walls very well. We have large windows upstairs which make it cooler but comfortable compared with the basement where we watch TV in comfort. We keep our temperature at 69 during the day and 65-66 at night. All rooms in the basement have cold air returns as well which really helps. We also have ahigh efficiency Carrier furnace. Look at whether you really need the two zone system. Is it worth it after you spend so much insulating the basement?

Come to think of it, is there an insulated wood door? I think we need to look into that…