Should You Close Vents in Unused Rooms?

September 29, 2021   By Lisa Iscrupe

Should You Close Vents in Unused Rooms?

It may seem like closing vents in unused rooms would save energy and money by reducing heating and cooling costs. It’s less square footage to heat or cool, right? However, it’s a common misconception that closing vents in unused rooms can actually save energy. Find out why and what to do instead.

Should you close air vents in your house to save energy?

The short answer is no; you should not close air vents in your house. Closing vents can actually waste more energy than operating your system normally. How does closing air vents waste energy? Because when you close vents in unused rooms, your central air system will push the excess air to other places in your home. Let’s take a look at what happens to all that extra air.

Why would you want to close vents in your home?

  • A room is too hot or too cold
  • You have rooms you rarely or never use
  • You believe it will save money or energy

What happens when you close air vents in your home?

Your HVAC system is built to heat and cool your home based on size, so you are throwing off this delicate balance if you close vents. Closing several vents makes the system have to work overtime to heat or cool the rest of your home and can increase air pressure through your home’s duct system. This increased pressure is not detrimental to your HVAC system for a short time but can cause issues if left unchecked long term. 

Static pressure in your air vents

According to Dominion Service Company, “Static pressure is one of the most important factors in HVAC design. Simply put, static pressure refers to the resistance to airflow in a heating and cooling system’s components and ductwork.” Closing vents will increase pressure, which can restrict or stop air pressure within your home. Along these lines, keeping doors closed to interior rooms for extended periods can cause the same HVAC response as closing vents, so it is generally not recommended. 

The one exception: If your heating and cooling systems are separate, which is typically the case only in an older home, in which central air may have been added to the house later. 

Issues that static pressure in-home air vents can cause

  • Can cause leaks in the HVAC system
  • Can make existing leaks worse
  • Makes the HVAC system less efficient
  • Can cause carbon monoxide leaks if the infrastructure is damaged

What’s the solution?

We recommend keeping vents and interior doors open as much as possible. However, if that’s not the case, try closing vents only partially. Closing vents 50-74% of the way can ensure that air keeps circulating throughout your home and can help keep your energy bill low. 

Regardless of how many vents you have open, the heater or air conditioner produces the same amount of air. The added pressure from closing a vent can cause air leaks in your system, causing long-term and unnecessary energy waste. Air leaks cause the unit to work harder as it tries to make your home comfortable. In addition, shutting vents could damage your AC or heater, leading to inefficient operation and costly repairs.

So does it save energy to close vents in unused rooms? The answer, unfortunately, is no. You are better off keeping the vents open to ensure the unit operates efficiently. This way, over the lifetime of your system, you can save on energy use and repair costs.