HP w/Furnace or Furnace Only in South Michigan

[Dave2001]

I'm looking at replacing my ancient gas furnace and want to add AC to house. Trying to decide if I want to go with a HP and furnace, or a furnace and AC unit. In southern Michigan there are several months below 30, and I just don't know if the HP would be on enough to save me any money.

Any thoughts?

Thanks,
Dave

[tigerdunes]

Dave

what is your electric rate?

what is your nat gas cost/therm?

If system is sized correctly, the heat pump in a dual fuel system will heat your home in the shoulder mths of fall/spring and be effective at outside temps above 30 degrees possibly even lower depending on insulation qualities of your home.

Here is a fuel comparison calculator link to help with your decision.

IMO
:)

http://www.warmair.com/html/fuel_cost_comparisons.htm

[Dave2001]

Hey, thanks for the link to the fuel costs comparison, I'll check that out.

Looks like my gas costs are 1.039 per CCF and electric is roughly .088 per KWH.

My house was built in 1929 and does not have insulated walls. Windows are in good shape though, and the attic is insulated.

[platchford]

Hey, thanks for the link to the fuel costs comparison, I'll check that out.

Looks like my gas costs are 1.039 per CCF and electric is roughly .088 per KWH.

My house was built in 1929 and does not have insulated walls. Windows are in good shape though, and the attic is insulated.

If I were you I'd go with the heatpump with gas furnace option. Your electric rates are reasonable. You will still have plenty of time every year where you will be heating the home and the OD temp is above 30 degrees. As I remember, winters in Flint weren't so cold as just windy because its so flat. Make sure they install a VisionPro 8000 series thermostat (or similar model from another manufacturer) with OD temp sensor to control the dual fuel.

Long-term I recommend you find a way to insulate your walls. Especially if you plan on living there a while. Icynene (http://www.icynene.com) is a foam insulation that can be added to existing walls utilizing their slow-rise formula. Any method to add insulation to your walls at this point is not going to be easy but it will save a lot of money in the long run. A big advantage to the foam insulation is it will prevent air infiltration and in a 1929 home I can guarantee you have plenty of that. Most likely is similar to my home with tongue and groove for the exterior sheeting which means lots of air gaps. Unfortunately, adding quality insulation to your home after replacing your heating/AC system will make it oversized. :(