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Closing AC Vents in Unused Rooms? That’s a Bad Idea

If you Google “home energy efficiency tips”, you’ll get millions of results. Some of the advice is good and some is bad. In this article we’re addressing one common “tip” that’s a bad idea—closing your air conditioning vents in unused rooms.

If you Google “home energy efficiency tips”, you’ll get millions of results. Some of the advice is good and some is bad. In this article we’re addressing one common “tip” that’s a bad idea—closing your air conditioning vents in unused rooms.

We’ll show you:

  • Why this myth is so common
  • How it hurts your wallet

Why some think this is a good idea

Close to half of your home’s yearly energy bills goes to heating and cooling your home. So when people want to cut their energy bills, cutting heating and air conditioning use is a good place to start.

And many people have rooms in their home that they don’t use everyday, whether that’s a formal dining room or a spare bedroom. They’re paying money to heat and cool those rooms, even when they’re not being used!

To minimize this waste, some say you should close the vents in those rooms.

After all, that’s how it works with most other things. If I want to use less electricity, I can unplug some electronics. If I want to use less water, I shut off water to parts of my yard.

Unfortunately, your air conditioning system isn’t that simple. Let us explain…

How shutting vents hurts your wallet

If installed properly, your air conditioning system is “balanced.” That means the ductwork was sized so that amount of air going into your air conditioning system equals the volume of air going out of your system.

So, when you shut some vents, you are messing up the balance of your AC system.

This causes a couple of problems.

Problem #1: Leaking or burst ductwork

When you close vents, pressure builds up in your ducts. And, rather than direct that air into your home, the pressure can cause small leaks in your ducts to become larger. And now you’re paying to cool your attic or crawlspace instead of your home!

Learn more about the 5 annoying problems with leaky ducts.

Problem #2: Your AC is less efficient

The buildup of pressure also means your air conditioner must work harder to distribute air throughout your home. And your air conditioner will run longer since it has to cool the same amount of space with less volume of cooled air.

Add that to the increased leaky ductwork, and your air conditioner’s efficiency can decrease dramatically simply by closing a few vents.

So what’s the solution?

Leave your vents open. It sounds counter-intuitive, but leaving your air vents open will use less energy than closing them.

And if you feel your energy bills are too high, contact us for help. We can help you determine of your air conditioning system is installed correctly and help you find other sources of inefficiency.

CoolToday is the Sarasota area’s leading air conditioning company. Contact us for more information.