I've been reading your forum constantly lately, trying to decide how to heat and cool our old house. I'm a rank novice, though, and my head's starting to spin I sure could use your thoughts.
Here's what I can tell you. Our house is 165 years old. Current heat is a Lennox oil furnace installed in the 1950s It's a dinosaur in every way but it works well, it's just that to stay warm we'll need another mortgage. Cooling is a 5-7 year old Ducane unit. The house is a clapboard with 2 1/2 stories with a finished English basement (brick foundation). 2600 square feet. It's obviously not very tight, but the exterior walls are insulated (don't know the R value) and we have 18 inches of blown insulation in the attic. Windows are original but have been restored, tightly weatherstripped, and we have good storm windows. Everything that can be sealed has been.
I keep hearing that an air-source heat pump won't keep us warm in an old house, not even in this climate. I tend to agree. Which leaves me considering LP gas (natural gas not available), a high efficiency oil furnace, or geothermal.
For what it's worth, cooling the house isn't a problem. Our highest power bill last summer was 2085 kWh/$196 for July.
What say you all?