Does closing bedroom doors help you save on heating or cooling costs?
While closing doors may seem to help improve energy efficiency, there are a number of drawbacks. (Photo courtesy of Angie's List member Benjamin D. of Philadelphia)
The heating and cooling system in your home is designed to maintain a constant temperature, no matter the season. But in the heights of summer's heat or the cold of winter the cost of running these systems can quickly increase, leaving homeowners to try ways to improve efficiency and lower costs. One common suggestion is to close bedroom doors - does this really work?
What's supposed to happen
The idea behind leaving a bedroom door closed to improve HVAC efficiency is that doing so limits the amount of air movement required as well as the space that needs to be heated or cooled. In turn, this should lower costs. On the face, this makes sense. The unoccupied room behind the closed door doesn't need to be the same temperature as the rest of the house. Instead of cooling a 2,000 square foot home, for example, a few closed bedroom doors could drop the number of square feet that need to be temperature controlled to 1,700 or even 1,500. Simple cost savings, right?
What actually happens
According to the nonprofit publication Home Energy, the reverse is true. When doors are closed, the room is placed under pressure; the door acts as a blockage to airflow. Air trapped in the pressurized bedroom doesn't stay contained, however. It finds ways to escape the house however it can. Any air lost is replaced in an equal amount, which can increase the amount of air being drawn from 300 percent to 900 percent, significantly increasing utility bills.
This replacement air comes through the chimney, water heater or furnace flue and creates a steady draft in your home. Because the air isn't coming through your HVAC system, it isn't being filtered, which means it contains everything from dirt and dust to humidity and carbon monoxide (CO). The result can be damage to your home or danger to the occupants in the form of high CO levels or possible mold or mildew growth.
Finding a solution
There are several options available to solve this problem, starting with cutting out a small section (approximately 14 inches) at the bottom of the door. But most homeowners don't want to see their bedroom doors — especially unique or costly ones — chopped up, even for energy efficiency. Leaving all the doors open is also a solution, but doesn't work if you have company, pets that like to sneak into rooms or older children who value their privacy.
It's also possible to install cold air returns in every room; this is a simple solution, but not always cost-effective, as holes must be cut and ducts run into every room. You can also choose to put in what are known as "transfer grills." These grills allow air to flow between hallways and bedrooms, but are opaque and can be placed into a door, above a door frame or beside the door. If you choose to install a transfer grill, it's always a good idea to hire a qualified HVAC contractor. Improperly installed, they won't circulate airflow as they should and may not solve your HVAC issues. In addition, not all doors are suited for a grill — professionals will be able to tell you if what you have works or if you will need to replace your door.
Summer or winter, closing your bedroom doors doesn't improve the efficiency of your HVAC system and may actually increase your utility bills. Leaving your doors open, installing cold air returns or putting in transfer grills are all effective ways to improve your home's air circulation.