If you lived in a part of the country that was unusually hot this summer, you probably counted on your HVAC system to keep you cool. Soon, the temperatures will start to drop again, and when they do, you will be counting on your HVAC system's furnace to keep you warm. If you don't want your furnace to unexpectedly stop working after the temperature drops, now is a great time to do preventative maintenance.

Here are three maintenance tips for your furnace.

1. Give Your Furnace a Tune-Up

A tune-up might sound like something you do for your car, but it's a good thing to do for your furnace, too. Just like on a car, a furnace tune-up can help prevent costly repairs. Giving your furnace a tune-up also makes it last longer. The first thing you want to do when giving your furnace a tune-up is inspect and calibrate the thermostat and set it to heat instead of cool.

Here are some other things to do during a furnace tune-up: 

• Lubricate all the moving parts of the furnace
• Look for signs of corrosion and rust
• Test carbon monoxide levels
• Make sure the furnace turns on
• Remove any clogs in the drain lines

If you are unsure of how to give your furnace a tune-up, an HVAC technician can help. An HVAC technician can also recommend any possible repairs that need to be made.

2. Clean the Furnace

Cleaning your entire furnace will keep it free of dust and debris, which helps improve the indoor air quality of your home. Before you clean your furnace, make sure it is powered off and the pilot light is out. To clean your furnace, wipe down the exterior with a damp washcloth.

You'll then want to vacuum dust from around the furnace. You can clean the blower with a small brush and vacuum and the blower assembly with soap and water. You should also clean the vents and remove any obstacles on or around them.

3. Change the Air Filter

Most HVAC professionals recommend changing the air filter every three months. This means you could change your air filter at the beginning of each new season. However, you may have to change the air filter more often if you have pets in the home or are allergic to dust. How often you change the filter also depends on the kind of filter and the size. If you don't run your furnace every day, you won't need to change it as often. For more information, contact an HVAC service.