Is it Okay to Run the Blower All the Time on My Furnace Without a Cold Air Return?

Reasons to Run the Blower Continually

• Some homeowners switch their furnace blowers from the “auto” setting to the “on” position so it runs all the time even when the furnace is not combusting fuel into heat. By doing so, you enjoy a constant circulation of air and a more even temperature in every room. Blowing air constantly through the furnace filter also helps remove more dust, which is beneficial for people with asthma or allergies. In the summer, running the blower motor continually can have a cooling effect.

Energy Loss Concerns

• The average duct system loses 25 to 40 percent of its heating and cooling due to the conductive properties of metal ductwork and air leaks. For this reason, some people suspect that running the furnace blower all the time will lead to increased energy loss as more air travels through the ducts. However, even when the furnace is off, air leaks in the ductwork can still lead to energy waste, so running an efficient furnace blower continually shouldn’t increase your energy loss.

Pressurization

• The issue with running a blower motor all the time without a cold air return is the pressurization that occurs. When you supply air into your home without vents to return it to the furnace, the pressure builds within the wall of your home. This pressure difference is undetectable and won’t cause you harm, but it leads to air leakage from the living space to the outside as the pressure attempts to equalize. It ends up costing you more to run your blower continually when heated air is pushed outside. Pressurization can even occur in homes with return vents situated in central locations if the doors to rooms with supply vents are closed.

Add Return Vents

• To get the most out of running your blower all the time, you should consider adding return vents. The installation is best left to an experienced HVAC contractor, who can make your heating and cooling system as energy efficient as possible. The result is lower utility bills, increased comfort and confidence that your decision to run the blower all the time is helpful rather than detrimental.