Air source heat pumps don't make sense in areas where winter temps frequently fall below 32 degrees. Once you get below freezing, you will be running the auxillary heat a lot. If you decide to go the air source route, you will want a second stage gas fired auxillary heat. I live in the mid-atlantic region in the mountains and selected GT. That choice was coupled with a blown cellulose insulation package. My other choice was a propane heat/electric AC with a foam insulation package. Both options were roughly the same install cost. Both would have provided similar energy efficiency. At the time we selected, propane was 3.75 a gallon and rising (with no end in sight) so we went with GT. The delta cost for the GT system (above the cost for a HE propane heat and electric AC system) was $15,000 for the heat pumps and loop plumbing (including pumps) plus $17,000 for digging the pit. The pit excavation should not have cost as much as it did but it is a 12 ton system and the hole was gigantic (120' x 48' x 6'). We live on a mountain and hit a bunch of boulders that required special equipment to get out. Rocky soil also required a 1' base of stone dust to cover the loop piping. The total cost for the GT HVAC system including all ducting was $50,000 plus the pit excavation cost of 17K. It is a large investment and I would only recommend it if you plan to live in the house a very long time. My heating bills are great - maybe 300 dollars maximum a month during peak winter for an 8500 square foot home (5900 living and the rest a condiitoned but unfinished basement). Make sure that whatever equipment you choose can be maintained by more than 1 very qualified HVAC company who has many years of GT experience. In my area there is only 1 GT company who has over 20 years of experience but I am stuck with them for maintenance. There have been times when I wanted to fire them but cannot. Local competition is a good thing. Also - if you build a tight home make sure that you consider ventilation and dehumidification in the HVAC design. I wound up adding both a whole house dehumidifier and energy recovery vent after we moved in becuase we had basement moisture issues as well as stale air in the winter. Tight homes are great for energy efficiency but can create health issues too. It is easy to deal with as long as you plan for it. Good luck with the build.

carl this is your third thread in about as many days on the exact same subject. I have re-read the other threads and you have received solid advice at no cost to you. I suggest you go back and read them again as well. for you, it is the question of heating comfort vs heating operating cost. you still perceive heat pumps from the old days where they developed a bad reputation. As stated previously, today's high eff systems are as different as night and day. The decision for me would be a no-brainer. I would not have propane for the Baltimore area/climate. If properly maintained, the question of longevity of HP vs straight AC is a moot issue. Plus as I recall you have a pellet stove for backup on a power outage or those extra cold days like our country experienced earlier this month. here are my minimum specs for new HP system 15 SEER, 12.5+ EER, 9 HSPF best matching VS air handler full BTUs in both cooling and heating for your rated size R-410a refrigerant(same as Puron) scroll compressor preferred electronic demand defrosat preferred thermostat with "dehumidify on demand" feature staged backup heat strips new and correctly sized refrigerant lineset you may want to take a look at attached link for fuel comparison calculator that might be helpful to you in your decision making process. IMO Good Luck! Here is a link that might be useful: Fuel Comparison Calculator

satester i really think your biggest challenge will be to find a qualified dealer in your area who has demonstrated experience with heat pumps. I would use the dealer locator for both Carrier and Trane and ask for heat pump customer references once you begin soliciting quotes. Elevation just is not an issue especially when comparing HP and inexpensive electric against expensive propane. IMO

It'll certainly, on average, cost more to heat than cool. A lot of areas now impose summer electrical rates which are higher than winter rates so they may be close. As for determining the cost effectiveness in relation to higher initial costs of higher SEER ratings, there may be more sizzle than steak. Compare the increase in energy savings with the higher efficiency units as opposed to the actual higher cost of a higher efficiency unit. The expected life cycle on a unit is 10 years so figure the energy savings you will experience in your area and see if it will shadow the initial and ongoing maintenance costs. Keep in mind the newer units also have a maintenance schedule that will be required by most companies, which is going to increase those costs. If your energy savings is more than the overall cost of the unit in a 10 year period, then it's worth it. But for the most part, I think you'll find it won't.