not knowing much on the subject, and seeing as it has already hit 38 here, what's the deal with heat pumps? they provide ac and heating down to -4? how much more efficient are they than a gas furnace? do you connect them into your existing ducting? approximate cost for a 2200 square foot house with a completely inefficient and uninsulated ceiling? gas bills in the winter range from 200-300 a month mostly for heat, in the summer it's around 15-30 as we have a tankless water heater. electrical bills average 100-150 a month as we have a hot tub running all winter, pool pump all summer, and an electrical boiler for the garage in floor. also we have a wall mounted ac unit that does cut the temps down a few degrees, it's older so maybe a newer, more powerful unit might do the trick? just wondering if it'd be worth it?