Downdraft Electric Heating & Cooling Units Vs. Updraft Units

Katrina Arthurs

Homeowners have two primary options for central heating and cooling systems in their homes: updraft and downdraft. Both units operate by pulling in air from the home, heating or cooling it, and then pumping it back into the home. Installation location and energy efficiency are the key factors in determining which unit is right for your house.

Heating and Cooling

Updraft heating and cooling units are more energy efficient than downdraft units.

The furnace generates heat either through electric coils or the combustion of natural gas. Air from the home is forced into the unit through return ducts and then blown over the heat exchanger. The furnace then blows the resulting warm air back into the house.

The air conditioning unit consists of an outdoor compressor unit and an indoor coil installed on the top of the furnace. A refrigerant cools the coil. Warm air from inside the home is pulled into the system and blown over the coil. The resulting cool air is then pumped back into the home.

Updraft Units

In an updraft heating and cooling unit, air is sucked in through the bottom of the furnace and expelled through the top.

Updraft units are installed in basements or large crawl spaces. The air is forced up through duct work attached to the unit that runs underneath the house to various vents installed in the floor.

Downdraft Units

Downdraft heating and cooling units bring air in from the top of the furnace, where it is warmed or cooled and forced out through the bottom.

Downdraft units are installed either on the ground level of the home or in an attic. Depending on the type of foundation, the main floor vents will either be on the floor or ceiling. If there is sufficient room under the crawl space, flexible metal tubes can be installed under the house. If there is not, the duct work will be installed so that the vents are in the ceiling, forcing the air down.


Updraft heating and cooling units are more energy efficient than downdraft units. Because heat naturally rises, updraft units do not have to work as hard to distribute the heated air. Downdraft units have to work continuously to force the air down. As a result, downdraft units are most commonly installed in mobile homes and slab foundation houses that lack either a basement or adequate crawl space to accommodate an updraft unit.