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The Myth About Closing Unused Registers

One of the most common misconceptions that exists in the world of home heating and cooling is that you can save energy or better divert the flow of air by closing up vents in rooms you’re not using. This may have been true once upon a time with old HVAC technology, but these days it can actually do you more harm than good to follow this outdated advice.

Here’s some information from our professional duct cleaners in Weber County, UT about why this myth can be so harmful.

How your home ventilation works

Your house is a mostly closed ventilation system, with filtration that cleans the air. There’s nothing moving the air internally—a blower fan is in charge of circulating the air, and the moving air carries heat or air conditioning around your home. There are also a couple different types of motors used in these blower fans, one of which is a variable motor that adjusts its operation based on the amount of air pressure it gets, while the other constantly runs at the same rate regardless of the conditions. The second is more common, because it’s cheaper, but it also is more likely to cause problems with efficiency given its lack of flexibility.

With a continually running fan like that, the fan is likely working harder than it needs to as it moves air through a smaller space. The air in your home continues to cycle, and as it leaves a space, more air will replace it. If you close one of the air vents in your home, you reduce the number of places the moving air can go, which restricts airflow and can cause problems with air pressure.

Keep in mind that your HVAC system has been specifically chosen to fit the size of your home. Your blower fan is able to move an amount of air that is ideally suited for your ventilation system’s flow rate and your home’s size. If you restrict airflow by closing vents, this becomes problematic because the increased pressure results in air flowing at a lower rate, making it more difficult to carry heat throughout your home.

Even if you do have a variable motor, this can still be problematic. While the fan motor can ramp up to increase airflow against the additional pressure caused by closing vents, you are still expending more energy to make up for that decreased airflow, meaning you’re not getting the energy savings that are basically the entire purpose of a variable motor system.

So, if you’ve been closing vents to try to save money on heating your home during the winter, it’s better to look into other ideas, including adjusting the thermostat so your system doesn’t run as frequently, upgrading your home’s insulation, sealing windows or leaving doors open for better, more even heat distribution throughout your home.

For more information about your home ventilation system and how it can operate most efficiently, contact the professional duct cleaners in Weber County, UT at Fresh Ducts.