Wow, that's like asking what kind of car to buy. Depends on what you have in place now or if it's a new installation. Gas forced air is the most popular, followed by all electric. Both can be adpated for air conditioning. Trane, Carrier, Amana, Goodman are all good brands. You should look for one with a high SEER rating and a 90% or better efficiency rating. Space should also be considered and Btu/H for the amount of space to be heated. Another factor is how well insulated your walls, floor and attic is plus the type of windows you have to determine air and heat loss. I would get at least three contractors to give you estimates before making a deision. I recently replaced a 75,000 Btu/H gas furnace with A coil for about 70 cents per square foot of living space.


