A furnace is critical to home comfort. Not only does a furnace keep you toasty warm in the winter, but it is also responsible for moving air in the summer for air conditioning. The type of furnace you have installed will affect efficiency and comfort year round.
A furnace is rated with an Annual Fuel Utilization Efficiency (AFUE) rating. This represents the percentage of fossil fuel that is actually converted into heat energy. So a furnace with an AFUE rating of 80% is wasting about 20% of your fuel. High-end furnaces achieve 96-98% AFUE with a few different types of technology:
- Modulating flames: A flame in the furnace heats the metal heat exchanger which transfer heat energy to the air. In the past, the flame was either all of the way on, or wall of the way off. Now you can purchase a furnace with different “stages” of heating, which simply means the flame level adjusts based on the need. If it’s a brisk fall day, you don’t need the furnace running at full capacity. Modulating flames take it a step further by adjusting in 1% (or close to that) increments.
- Condensing technology: Heat energy was wasted in older furnaces due to escape during exhaust of combustion gases when heating the heat exchanger. Furnaces with condensing technology feature a second heat exchanger used to gather heat energy from this exhaust that was quickly discarded in the past.
- Variable speed fan motors: These are not only more efficient, but they are very quiet. In an old furnace, the fan was either blasting or completely off. Now, fans can run at different speeds for optimal comfort.
Below you can read more about different models of furnaces. A general rule of thumb is that if you’re in southern, milder climates, you don’t need a high AFUE. You just want a variable speed fan motor in the furnace. If you’re freezing in the North, that higher AFUE is going to save you money.
Find an HVAC Dealer is not under the obligation of any manufacturer to show certain equipment. The manufacturers and models we show are purely what we feel like featuring, and are not meant to be an official list of the best.