An annual checkup can keep you healthy. Changing the oil regularly can keep your car healthy. Want to keep your house and your heating and air conditioning system healthy? Check your system’s filter every month, and if the filter looks dirty, change it. The U.S. Department of Energy suggests that filters be changed or cleaned at least every three months.

How does something as simple and inexpensive as changing a filter make a difference?

• A dirty filter reduces airflow. This makes the system use more energy to heat and cool your home and makes it work harder, potentially shortening its life.
• Clean filters keep particles from building up in the system that can lead to breakdowns and reduced equipment life.

Checking the filter can help diagnose potential problems. If the filter is very dirty after 30 days, check it more often. If it’s dirty after only a few weeks, it may be time to call a heating and cooling contractor to check for problems such as leaky air ducts. Also, the filter should fit snugly with no air leaks around its frame.

Even if you don’t see these signs of trouble, it’s a good idea to have your system checked by a licensed contractor at least once a year. If you’re having trouble changing your filter, ask the technician to show you how to access and change the filter.

How to Change Your Filter

• Turn off the power to the system’s fan at the main circuit breaker.
• Remove your current filter and write down the dimensions so you can get a correctly sized new filter.
• Immediately put your old filter into a plastic bag, seal it and discard.
• When installing the new filter, look for printed arrows that show the correct direction of airflow through the filter.
  
• Write the date you change your filter on the side of the filter so you’ll know when it’s time to change it again. For instance, if you have a three-month filter, the written date will remind you when the three months are up even if you can’t tell by looking at the filter.