Furnaces

As part of a central heating and cooling system, a furnace converts fuel into heat, then uses a blower to circulate warm air throughout your house. In summer, a furnace works with your heat pump or air conditioner to deliver cooled air throughout your home. The main components to a natural gas furnace include burners, a heat exchanger, blower motor, and controls.

AFUE stands for annual fuel utilization efficiency. This industry rating measures the annual efficiency of a furnace. A higher AFUE means your heating system is more energy efficient. You can learn more about AFUE here.

Determine if your furnace may need to be replaced or repaired with our Repair or Replace tool. We recommend replacing your furnace if it’s 15 years old or more, has an AFUE of less than 80%, needs frequent repairs, is declining in performance or your energy costs are rising.

If you do need to replace your furnace, consider the AFUE rating, heating stages, and cost of your new unit.

The higher the AFUE, the less fuel you'll need to keep your home comfortable. Trane furnaces with 90 or higher AFUE measurements deliver at least 90% of the heat they create to your home, which exceeds the government’s minimum standard of 80 AFUE for new furnaces.

If you have a furnace that is at least 10 years old, it probably has an AFUE between 60 – 70, meaning you could be losing 40 cents of every dollar you spend on heating energy.

A gas furnace uses natural gas for fuel and distributes heat to your home. Oil furnaces convert oil into heat energy that is then distributed to your home.