Edwin Pawlowski:

Do some energy comparisons first.
1000 Watts (1kW) = 3412 Btu
1 therm = 100,000 Btu

I found a website that states there are 26.85 kilowatt hours of electric
energy in one gallon of propane, so if I multiply the cost of electricity
by 26.85, it should give me the equivalent cost of electricity vs propane.

I suppose the efficiency of the central unit plays a factor... the
baseboard heaters would be 100% efficient I believe, I don't know the
efficiency of the central unit but if we use 80%...

26.85 * $.081 KWH = $2.17 (electric)
wintertime propane cost + inefficiency** = ~$2.40 gal.
summertime propane cost + inefficiency** = ~$1.80 gal.
average propane effective cost = $2.20 gal.

If this is right then it's roughly a wash. Sound right?
--
Mac Cool

** I assumed $0.20 of each dollar spent on propane is wasted, so I added
20% to the price.