Help with choosing system, please!

[1894House]

Is it worth spending the extra money for a high efficiency furnace if it is going to be used as back up?

We live in a two-story, 100+ year old house in northeastern Maryland and are looking at doing two systems. We also have a quote for a single system.

Here goes...

Two-systems Option 1: Lennox G61 MPV-36B-45 gas furnace, XP16-024-230 2-stage heat pump, coils are CX34-36B-6F and CH33-36B-2F.

Two-systems Option 2: Lennox G61 MPV-36B-45 gas furnace and single stage heat pump XP13-024-230, coils are CX34-36B-6F and CH33-36B-2F.

Since these are two separate systems (each floor ~1000s.f.) could we step down a grade with the furnace and still have an efficient set-up?

Single system Option: Lennox G61 MPV-60C-90 gas furnace, XP16-048 heat pump, coil CX34-60D-6F.

We currently have an oil furnace and will be purchasing a 500 gallon underground propane tank in addition to installing a Rennai tankless hot water heater, so this project is getting quite pricey.

I want efficiency, but I also don't want to break the bank. Any suggestions would be greatly appreciated!

[beenthere]

I'd get a 90% atleast for the first floor. The first floor will run more often then the second floor. Hot air rises, cold air falls.
So the first floor will switch over to gas sooner, and for longer periods of time then the second floor.
You don't need 2 stage heat pumps. But they will increase your comfort level, and help to control humidity in the summer..


PS: Have your contractor estimate how much LP you will use in a year. If a 500 gallon LP tank won't get you through to the summer, your better off with a 1000 gallon tank..
Last thing you want to do, is have to refill it up in the winter at its highest price.