The Unintended Consequences of Closing Vents

The Unintended Consequences of Closing Vents

It sounds like a great idea. One that you feel extra smart and special for thinking of. You’re not the only one, so many people have the brilliant idea that if they close a vent in a room you don’t use that often, you can redirect that heating or cooling into the rooms you inhabit more frequently. It makes sense in theory, however many older heating and cooling systems are not set up to support the significant pressure changes that closing particular vents could end up causing.


Air pressure changes in your duct system is the initial and most impactful consequence of closing individual vents. This can lead to some unforeseen problems that you might need to address. The first problem you may encounter is increased duct leakage. When you close the vents, especially if it’s multiple vents, you change the air pressure in your system, which could in turn, expose some of the weaker areas in your internal duct system. It’s good to know where these leaks are, however, it’s not a weakness you want to exploit.


This leads to our next issue with closing vents, which is: overworking the system. Older blowers have a fixed speed for the air pump. So, without a computer telling the pump that a vent is closed, it’s going to keep pushing the air at the same rate it always has. But this system was likely given a certain pressure to adhere to based on the number of vents, and the size of your house. Older systems are set to maintain a particular air pressure to make sure it always has enough “umph” to make it through your entire home. Closing random vents throughout the house will affect this equation.


This problem can cause our next and worst inevitability, which is the potential for a cracked heat exchanger. With the increased pressure, leading to the air pump having to push harder to maintain the same air flow – this could lead to a very dangerous outcome. A cracked heat exchanger has the potential of allowing the leak of the deadly gas, carbon monoxide. This is not a machine you want to become damaged in your home. It’s completely fixable (call us)! But if you are unaware of the damage, the consequences could be catastrophic.


There are numerous problems that can arise from closing vents in your home, too many, if we’re being honest. You could also end up having no issues at all! But it’s not worth the risk in our BOLD opinion. If you have any questions, or would like a system inspection – call Bold City Heating & Air at (904) 379-1648 and we would be happy to help