If your home suffers from high indoor humidity levels during the winter, you might be wondering whether a furnace will dehumidify it. Air conditioning systems, of course, are capable of dehumidifying indoor spaces. They will remove both heat and moisture from the air while subsequently transferring these elements to the outdoors. While running your air conditioning system can dehumidify your home, though, furnaces work in a different way.

Furnaces Don’t Remove Moisture From the Air

Unlike air conditioning systems, furnaces don’t remove moisture from the air. Furnaces work by generating heat. Electric furnaces have a heating element that, when exposed to an electrical current, becomes hot. Gas furnaces have burners that ignite natural gas. Air will travel over the furnace’s respective heating element or burner assembly so that it becomes hot.

Older Furnaces May Indirectly Lower Humidity Levels

While furnaces don’t directly dehumidify, older furnaces may still indirectly lower humidity levels. Older furnaces are atmospheric furnaces. They feature an open combustion chamber, meaning you can watch the pilot light as it burns.

Because they feature an open design, they can lower humidity levels. Older, atmospheric furnaces will pull air from the outdoors -- and due to the difference in temperature between the outdoor and indoor air – they will lower indoor humidity levels.

What About Heat Exchangers?

Heat exchangers, on the other hand, can dehumidify. Heat exchangers are complete heating, ventilation and cooling (HVAC) systems that work by transferring heat. You can use a heat exchanger to cool your home during the summer and warm your home during the winter.

While in cooling mode, it will transfer heat from your home’s interior to your home’s exterior. While in heating mode, it will operate in reverse: the heat exchanger will transfer heat from your home’s exterior to its interior.

Running a heat exchanger in cooling mode will directly dehumidify your home. Heat exchangers work like air conditioning systems while in cooling mode; they’ll remove both heat and moisture from inside of your home. As they pass stagnant air over a coil, heat exchangers will pull moisture out of the air. This moisture will drip into a condensation pan where it’s flushed to your home’s exterior.

Many heat exchangers also come equipped with a dehumidifying mode. It allows them to dehumidify during the cooler months of the year as well. You can run a heat exchanger in dehumidifying mode to remove excess moisture from inside of your home.