Expert Answer: Number of Return Air Vents Needed in Bedroom

Liz from Roseville, CA has noticed that the bedrooms in her house are regularly a few degrees warmer or cooler than everywhere else in her home. She’s heard that adding more return vents could, in fact, help balance this problem out. Liz asks:

“So, I have a confession to make: until recently, I didn’t know what return vents were. I’d heard the phrase, but I’d never really had cause to look into what they were or how they were different from other types of vents. I just needed to know how to open and close them.

Then, I started noticing that the master bedroom in my Roseville, CA house was almost always 3 to 4 degrees warmer or cooler than the rest of the rooms. It doesn’t seem to matter what I do. A friend mentioned that the number of return air vents I have might be the problem, but he didn’t know how to tell if that was my problem or not. So, I’m writing to ask my friendly neighborhood heating and cooling service techs a couple of questions: what are return vents and how many return air vents do I need in my bedroom?”

Liz, I’m glad you’ve asked this question In my experience, you are far from the only homeowner in our region who doesn’t know what a return air vent does but is likely having temperature control problems caused by not having enough of them. Quite honestly, Liz, this sounds like a classic case of not having enough vents for return air in your HVAC system, which means it could be as simple as adding another one to your master bedroom, although I’d have to take a look at the situation myself before making that decision.

With all that in mind, though, I’m going to start today off by explaining what return air vents do and then I’m going to give you a rough estimate of how many return air vents you need in your bedrooms. As with so many HVAC topics, the answer will vary depending on the exact parameters of your home, but this should give you some idea of your situation—and whether or not you need to enlist the help of your friendly neighborhood HVAC service tech like Liz did.

What Are Return Air Vents—and What Do They Do?

One of the lessons that has served me well in life is that it’s okay to not know everything, as long as you follow in Liz’s footsteps and ask an expert for help. I don’t know why more folks don’t ask what return air vents are. They’re in every home, but, like Liz, homeowners so rarely have cause to deal with them that many have never given them a second thought.

To put it as simply as I can, return air vents suck air from the rooms in your house in order to return it back to the heating and cooling system through your ductwork. It is then heated or cooled once again before being pushed back into your house to make you comfortable.

The other type of vents in your house are supply vents, which are the openings where conditioned air is blown out. These are easy to identify because they’re the ones that you feel air coming out of. Another tell-tale sign of which vent is which is their size. Return vents are almost always larger than the supply vents, and, of course, you don’t feel air being blown out of them. In fact, you probably don’t feel much of anything since the air suction doesn’t need to be very strong for the vent to do its job.

The Big Question: How Many Return Air Vents Do I Need?

How many return air vents do I need in my bedroom—or anywhere else for that matter—is such a big question because not having enough of them, or having problems with them, can make life really bothersome. Some of these problems are harder to notice, like dust in your return ducts irritating your Sacramento allergies, while some of them are pretty clear, like Liz’s always too hot or too cold master bedroom.  

Certain rooms in a house being cold is a common complaint in Roseville where Liz lives, especially in neighborhoods that date back to the 1950s. Houses built back then just weren’t designed for the modern HVAC technology that we use today. I mean, it sounds hard to believe, but there were actually still furnaces that used wood or coal being installed in new homes of that era. Gas or oil-fired furnaces distributed heated air throughout the house using an internal fan. Furnaces were always on the bottom floor of the house, and the upper floor was simply left to make do with much poorer heating.

The simple answer is that if Liz has a cold master bedroom, she needs more return air vents.

Enough of the history lessons, though. The simple answer is that if Liz has a cold master bedroom, she needs more return air vents. I can’t tell her exactly how many her house needs, but an HVAC system doesn’t ever lose function from having too many return air vents, although, at a certain point you’re not increasing function either. With all that said, my advice to Liz is that she should start by having a trained HVAC professional out to evaluate her situation. How many return air vents you need in a bedroom will depend on your unique home, furnace, ductwork, and many other factors that must be evaluated by an HVAC professional in person.

I can’t tell her exactly how many her house needs, but an HVAC system doesn’t ever lose function from having too many return air vents, although, at a certain point you’re not increasing function either.

Any experienced HVAC tech will be able to tell Liz the exact number of return air vents that her individual house needs to keep her master bedroom comfortable year round. Another issue I see all the time is that for many, many years, master bedrooms only needed one return air vent, but recent build cycles have led to homes where the master bedroom is far larger, i.e. a master suite instead of a bedroom, or is positioned in a way that keeps it secluded and shut off from the rest of the house, including the furnace. So, while you generally need just a single return air vent in your master bedroom, many homes these days are built in a way that may necessitate more.

At Bell Brothers, we’re happy to give folks like Liz a free in-home estimate; we have decades of experience adding return air vents. The best part for Liz, though, is that we can be out to take a look ASAP, so she won’t have to be uncomfortable for much longer.

At Bell Brothers, we believe in the whole-home approach to health and efficiency. Our trained HVAC professionals would not only be happy to give your furnace winter maintenance, we’d love to also make sure your windows, insulation, and ducts are working efficiently to keep your house warm this winter. Contact us today to schedule your next furnace servicing.

Wondering how to finance a new furnace, or maybe even new windows and plumbing? HERO is a unique financing option that helps California homeowners afford energy efficient upgrades to their home. Contact Bell Brothers, a HERO-approved contractor, to learn more. Our local HVAC, plumbing, and window specialists will walk you through the entire process, from applications to installation.

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