Keeping your home comfortably cool during the hot summer months can be expensive, especially if you live in a warmer climate. Opening your late summer utility bills can feel about as scary as stepping into a horror movie. Because summer cooling bills can be so frightening, homeowners often share their own theories about how to minimize the financial damage.

Unfortunately, not all accepted theories for cutting costs actually work. One common strategy for saving money on air conditioning, is to shut the doors to the rooms you aren’t using. The idea is that you won’t have to pay to cool unused spaces.

This prevalent strategy, although well-intentioned, will actually end up costing you more money. And it could also contribute to other indoor air problems.

Why You Need to Keep the Doors Open

Modern air conditioning systems are designed to function as a carefully balanced whole. When you close interior doors, you are essentially shutting off part of the system. This doesn’t strengthen the other parts of the system. Instead, it causes the whole system to work harder to keep your home cool.

Shutting doors to unused rooms forces your air conditioner to compensate for the air imbalances. Because closed doors cause your system to run less efficiently, you could actually be causing unnecessary wear-and-tear on your unit.

The Effects of Closed Doors on Your AC

Shutting the doors to unused rooms could actually be one of the worst things you can do. Closing the door to a room does not stop your air conditioner from blowing air into that room. As the air blows from your open vents, it can build up inside the room and affect the air pressure.

Most air conditioning systems incorporate supply vents in every interior room. However, many homes are designed with a single central intake. Closing interior doors blocks the intended air flow, creating an imbalance, reducing the air volume returning to the air conditioner.

As your system continues to intake air to cool the entire house, the pressurized air behind your closed doors is naturally looking for a way out. Often, the easiest escape route is through cracks in walls and gaps around windows. The result is often a negative pressure in the part of the home left open, causing outdoor air to push in through any small space or crack it can find.

Maintaining Air Flow and Personal Privacy

Reducing utility bills isn’t the only motive behind closing doors. For some family members, shutting doors is a matter of privacy. This can be especially true for households with teenagers and extended family members.

If there are rooms that must be closed regularly for issues of privacy, there are measures that can be taken to ensure cooling efficiency. One option is to have airflow grates installed in each interior door. This allows air to flow freely even when the doors are closed.

Contact your local HVAC professionals if you have questions or concerns about maintaining proper air circulations while preserving privacy.