The DOE has worksheets that can help you calculate the relative cost of heating and cooling with different systems using your current energy costs. Of course you need to predict the relative costs over the next decade or two to really tell what is best. How is your crystal ball working? I would like to clear up a couple of common misconceptions. One type of heat does not dry a house in the winter any more than another. Leaky house envelopes dry houses. Heat by flame of some sort might dry a house more because they draw more outside air in if there is not a source of outside combustion air. That would be the only mechanism. There is nothing special about heat pumps in poorly-insulated, leaky homes. No heat or air conditioning source works as well in that situation as well as they do in tighter, well-insulated homes.

All units are Bryant Furnace = 355BAV A/C = 127A Heat Pump = 226A Had to order today to take advantage of rebate offer that ends 8/31. Never could figure out how to estimate the cost of running the heat pump vs. the gas furnace and couldn't locate any on-line calculators/spreadsheets that would help. Figured I'd save a bunch with new 95% furnace over the old sigle-stage 80%, and the new 17 SEER a/c over the old single-stage 10. It's small house (1450 sf) and well insulated, and I didn't know if I'd squeeze enough additional savings with a heat pump to justify the extra initial cost of the pump plus whatever extra cost would be involved in replacing it sooner because of running it much more. When in doubt, play conservatively (at least where money is involved), so I went for the a/c unit. Wish I'd discovered this website a month earlier. Thanks to all those who responded.

Post your electric rate in cents per kw-hr, and your gas rate in either $ per ccf or $ per therm. The heat output of a gas furnace is very similar to electric resistance strips if enough kw are used. Utility costs decide which is cheaper. 5 kw electric strips put out air temps about 15F greater than room temperature. So a typical 10kw strip heat puts out 100 degree air if the room temp is 70F (70 + 30 = 100). This# is based on 1200 cfm air flow from the indoor fan. 15kw = 115F which is more in the range of gas furnace temps. The air handler must be sized to handle this heating load. These temps are for the strip heat only and do not include any btu's from the heat pump. The heat pump itself puts out air temps from about 90F to 100F based on outdoor air temps. The 90F supply temp air from the heat pump combined with 20 kw aux electric strips provides minimum 120F output air when needed. Heat pumps provide enough heat up until the balance point, which is around 32F or so based on home construction/insulation (mine is 25F). At temps lower than the balance point, aux heat is needed - either furnace or strips. The good thing with the strips is they can run along with the heat pump. The furnace cannot run when the heat pump is in heating mode; its one or the other. When the heat pump goes into defrost mode, the air output is in the low 50's. 10 kw provides 30F to temper the air into the low 80's so it doesn't feel too cold while the heat pump is defrosting. The furnace will provide 120F air during a defrost cycle. The heat pump is typically 300% efficient down to 35F ambient. Heat pumps make cheap heat. One comment about the XP-19. It's "up to 19 SEER". Not all combinations get 19 SEER. Model numbers can be used to determine actual SEER. Also, dual-compressor systems like the XP-19 are more for hot and humid summers than for heating. In the cooling mode, running on 1st stage saves $$ and reduces humidity. Once on 2nd stage, it loses its operating $$ benefits. A 14/15 SEER usually provides the best combination of purchase price and operating cost. If you can afford a "19 SEER" system, go for it. Whichever SEER you get, you want as close to 12 EER and 9 HSPF as you can get for low operating costs in cooling and heating respectively. Good luck.

You are right on the cusp with a 20 yr old gas furnace of when the codes changedand the requirement of all gas equipment was for a minimum of 78% efficiency. That was '93. The question is, is yours one of the newer units or did they put in the older style. If the older, then you may be looking at a 60% efficient unit. Also, those being new designs there were some problems with those "new" units at the time. l guess after 20 yrs we can call your ok;) Although the previous owners remodeled I would make my mshp/furnace decision almost solely on the condition of the duct system. You need to have it pressure tested for leakage. Google "doeductleakage" to see what I am talking about. If the duct system passes muster then the new furnace is a choice. If it doesn't then it is not. It is not worth spending the money to repair it. I pulled all my ductowrk out and went mshp and Rinnai Energysaver (all Net to the space heating/cooling with no duct or duct losses) As a result, with the elimination of the ductwork I found two good size closets and a large storage area under the stairs and we are very comfortable.