most heatpumps, when operating in heat pump mode (not using backup resistance) will only put out air slightly warmer than the air in the room. They don't have the several hundred degree heat exchanger found in a fuel fired furnace. That doesn't bother me as I had a rather good air-source heat pump at my old house. Gas is available at the street, but while the wholesale price of gas (close to the wellhead) has gone down, the retail price we pay is still up there and likely to stay as high as the suppliers can get away with. The grond coupled system looks the best to me, just want to be sure to get the biggest ground loop I can afford(or maybe a bit bigger than that!). House was built for caol fireplaces and I have actually thought of putting in a couple of small coal stoves for supplimental heat. Eventually, as I tighten up the house, that could be a problem.