Ted:

For a fuel comparison, compare the cost of 1 million btu's of heat for several fuels. Insert your own costs and efficiencies for a more accurate number.

Propane at $3/gallon, 80% efficient furnace:
(1,000,000 btu / 91,000 btu per gallon) x $3/gallon / .8
= $41.21. $36.63 for a 90% efficient furnace.

Oil at $4.50/gallon, 80% efficient furnace
(1,000,000 / 139,000 x 4.50 / .8
= $40.46

The difference in the operating cost of oil heat and 80% efficient propane furnace is negligible (2%) at the above prices. 90% propane furnace is almost 10% cheaper.

With today's prices, oil and propane are now the most expensive heating fuels.

Electric resistance heat w/electricity at 12 cents per kw-hr delivered:
(1,000,000 / 3413 x .12
= $35.15

Heat pump w/electricity at 12 cents per hw-hr, COP = 3.25 at 35F ambient
= 35.15 / 3.25
= $10.82

Heat pumps produce cheap heat but require auxillary heat as outdoor temps drop below 32F or so.

Wood Pellets at $225/ton, 90% efficient pellet stove:
(1,000,000 / 16,500,000) x 225 / .9
= $12.27

Good luck.

I agree with Ted but find an online estimator to avoid most errors.

The biggest question is really not what the new system costs but how quickly it will pay for itself and put money back in your pocket.

That was my concern when I put in geothermal payback was 4 1/2 years and I've had 18 yrs now. Waterfurnace

that was my question when I added outdoor wood stove at the office. Check out the online savings estimates

Now the new question ...will it qualify for tax rebate
my new outdoor pellet stove should qualify me for $1500 back because it's 92% efficient and doesn't contribute to net carbon dioxide in the atmosphere like fossil fuels.

Renewable energy from sawdust.
Hope this helps

Dale

Here is a link that might be useful: Central Boiler