Does Closing Air Vents Actually Save Energy?

air vent

Closing your vents to save energy sounds like an obvious solution to high energy bills. Closing off vents in unused rooms means less square footage to heat or cool, right?

Sadly, this logic doesn’t hold up. Instead of saving energy, closing your vents can actually cost you money.

What Happens When You Close an Air Vent

Your HVAC works by pulling air from the house through the return ducts and then pushing it back into the house via the supply ducts. Closing a supply vent doesn’t decrease the amount of air flowing through the system, it just forces it elsewhere.

This increases the pressure within your vents. At this point, any air duct leakage gets much worse, as the increased pressure forces even more air out of the leaks. It may even expand those leaks.

Also, depending on the type of blower your system uses, increased pressure has two other likely outcomes:

  • A PSC (permanent split capacitor) blower cannot overcome the extra pressure and have lower air flow – meaning it will take longer to heat or cool your home
  • ECM (electronically commutated motor) blowers can overcome the pressure but you will see this extra effort as an increase in your energy bill

How Closing Air Vents Can Harm Your System

Other consequences of closing your vents can result in damage that requires replacement parts. Or, if you don’t have a warranty, an entirely new outside system or furnace.

For example, because PSC blowers slow down when you close vents, you risk damaging your air conditioner’s evaporator coil as well as your furnace’s heat exchanger.

  • Heat exchangers can overheat and even crack with a lack in air flow. Cracks allow exhaust gases to mix with conditioned air. In some cases, it can send deadly carbon monoxide into your home.
  • Air conditioner coils can become too cold and become encased in ice. Liquid refrigerant then destroys your system by flowing back into the unit’s compressor.

air vent

Additional Consequences of Closing Air Vents

Besides energy bill increases and possible extreme damages, closing air vents may cause other issues. The lower surface temperatures in rooms with closed vents may lead to condensation and mold growth during winter months, causing more headaches and costly repairs down the road.

Solutions to Save Energy

The examples provided here are some of the more intense issues that arise from closing your air vents but for the most part these issues won’t appear over night. So, if you’ve already started closing off your air vents, you can still find a better way to save on energy bills.

Alternative solutions include lowering your thermostat in winter and drawing the blinds in unused rooms in the summer – just remember not to close your air vents!

For more tips and advice on how you can save energy today, contact the trusted professionals at D&B ClimateCare directly.