What is the most efficient furnace?

Hello Foxy777,

If you mean brand of furnace, there is no answer. But, the efficiency of a furnace is measured by its SEER rating. (Seasonal Energy Efficiency Rating)

The higher the SEER rating the more efficient the unit. Lower SEER ratings of 13 are at the bottom of the scale, higher ratings of 20 can now be had but the cost of these units is considerably higher than the lower SEER units.

Hope this helps.

Carrier gas

it has been natural gas if you can get it,but with the cost of fuel going up,there is a good reason to look into alternative heating sources,efficient burning wood stoves are good especially if you can harvest your own firewood.

You didn't say what kind of fuel you're using, or what the heating system is (air, radiant, baseboard, etc.).

If you're using natural gas or propane, go for a multi-stage modulating furnace. A rating of 92 to 97 percent efficient is good nowadays. Check for the followign manufacturers:
Rheem, Trane, Bryant/Carrier, Lennox, Tempstar, or York.

For a high-efficiency oil furnace, look for Adams Manufacturing. They sell a forced hot air oil-fired furnace that is 93 - 95% efficient. I installed one last year in my 230-year-old farmhouse in New England, and my fuel bill was cut by about 25% last year.

Wood burners are not very efficient, and many states are outlawing the outdoor unit due to smoke pollution concerns. If you have a large woodlot and the time to cut wood, you can save some out of pocket $$, but you'll spend a lot of time heating your house with a furnace that MIGHT be 80% efficient.

In terms of heating and cooling the most efficient systems made are called ground source heat pumps. Ground source heat pumps use the temperature of the ground to keep your home warm or cool, depending on the season. A large enough property with easy to dig soil is required. Ground source heat pumps cost about twice what a normal heating and cooling system does but have a SEER rating of over 25. Fore more on which furnaces are most efficient you can read the following article: http://savegreenly.com/heaters.htm

Condensing Furnaces are very efficient, they are called Condensing furnaces because the Btu output is so high (actual heat being used to heat your space) that the water vapor in the flue gas (Byproducts of combustion) actually condenses into liquid water, because most of the heat is being used, hence the name condensing furnace. Now, that warm liquid water that condensed from the flue gas runs into a secondary heat exchanger which actually pre heats the air before it passes the primary heat exchanger which makes the furnace even more efficient. I believe that condensing furnaces have a rating of 95%+ AFUE (Annual Fuel Utilization Efficiency)