This forum was a great help 5-6 years ago. After poking around I installed a zoned Bryant Evolution system in my house: NG Gas furnace/AC. This system is fantastic: unbelievably quiet, comfortable and very efficient ... I had one relay die this summer - covered by the 10 year warranty -- also suggested. The recommendations advising this system because of the conventional compressor and the better humidity control on the lower output has ben spot on.

I recently experienced a fire in another home that will be now be gutted and the two current old oil furnaces/ AC units will be removed. The house is a converted church and one of the units had the ductwork placed under the slab - obviously going. If I had natural gas available installing two Bryant systems similar to the other house would be on the top of my list -- maybe going to the heat pump versions ..... But the only gas available is propane. So I'm not sure what is the best way to start to think about this.

If I did the two Bryant/Carrier heat pump systems -- one would need to be zoned. What would I do about back-up heat? Is it crazy to think about installing an oil fired boiler and heat exchangers in air handlers? Then I could install a hot water storage unit. This house is not used all the time is basically a weekend house -- and I don't use it much in the summer (but I want a well designed AC system). The reason I mention: I turn the heat down when I leave in the winter -- normally to about 57 -- Also turn off the water heater. When we return to the house I turn up the two systems to 71 and flip on the oil hot water heater. Hot water in about 15min and the house is fine in about an hour with the high heat from the oil furnaces ... this is not going to work with a heat pump and I don't want to have an electric water heater running all week.

So what to do ... I have a small detached studio that is heated by propane - it has a nice through the wall heater ..induced combustion (fan forced) heater about 83% efficient - and it costs me a fortune to heat the building with $4.50 gal propane in our area. I don't think I want to have propane back up ... but maybe in the end it would be cheaper to do the propane and install a heat pump water heater.

If I did the boiler I could also do some radiant heat ... I guess. I'm also wondering if installing a heat exchanger drops the efficiency of the heat-pump in any way.

So is it crazy to even think of using oil back up heat? I don't think I would be able to use two oil furnaces (if they even work with the Bryant systems. The one unit will need to be relocated to remove the under floor ducts and a proper oil flue for that unit would be difficult to install. In fact I would have to rebuild a proper flue/chiminy for the any new oil boiler .. Unless the direct vents units are reliable now.

Any thoughts ... or directions to point. Thanks