Many homeowners believe that closing heating vents in unused rooms saves energy and reduces heating costs. It sounds logical—if you’re not using a room, why heat it? But modern HVAC systems don’t work the way most people assume. In fact, closing vents can increase energy use, strain your equipment, and create comfort and air‑quality problems throughout your home. Here’s why keeping vents open is the smarter, safer, and more efficient choice.

1. Closing vents can damage your furnace or A/C. Higher pressure in the ducts doesn’t just reduce efficiency—it can shorten the lifespan of your HVAC system. The furnace can overheat and heat exchangers can crack, which is a major safety hazard. In summer, A/C coils can freeze up and lead to premature blower motor failure.

2. You won’t actually save money. Closing vents often increases energy use, because the system still runs until the thermostat is satisfied. Higher pressure makes the blower less efficient, and the furnace cycles more frequently.

3. Closed vents can create hot and cold spots. When airflow is restricted, temperatures become uneven throughout the home. Rooms near the thermostat overheat, while distant rooms become too cold. Overall comfort is reduced due to drafts and temperature swings.

4. Pressure imbalances can affect Indoor Air Quality. Closing vents can create pressure differences that pull air from undesirable places, leading to increased dust, air filtration from attics or basements, higher humidity levels, and mold risk in colder rooms.

If your goal is to save energy or improve comfort, there are far more effective strategies. Use a programmable or smart thermostat, seal and insulate ductwork, improve attic insulation, or upgrade to a variable-speed furnace or heat pump. Zoning systems can also be used to control airflow.

For more tips about improving comfort and air quality throughout your home, please call KM Heating & Cooling at (815) 691-1991 and ask for Dave Kissel.

KM Heating and Cooling

339 Wurlitzer Dr.

DeKalb, IL 60115

Ph: 815-691-1991

KMHeatingandCooling.com