When you drive your vehicle, you may casually glance at the corner of your windshield and see the sticker that reminds you when it will be time for the next oil change. If you go too long without addressing the dirty oil (and old oil filter) it can lead to trouble for your car’s engine. Your furnace filter is very similar: It also needs to be changed periodically to avoid larger troubles happening farther down the road.

There are several reasons why you should regularly replace your furnace filter:

Put simply, air filters keep your furnace clean. An air filter is essentially a fine mesh screen. As air from the house passes through the screen, particles get caught in the filter. The filter catches the dust, hair, and particles that would otherwise build up inside the system. Without it, all those particles end up in the furnace itself and impede the air flow. This leads to an inefficient system and those inefficiencies have a way of making your energy bill higher.

You can’t just forget about it! Left unchecked, caught particles can build up on your furnace filter until eventually the filter is too thick with grime to let air through easily. The blower and other components have to work harder and harder the longer the filter goes unchanged.

Let us be your helpful reminder. Each month when your electric bill comes, take a moment to look at your filter. If it is too dirty or damaged, your furnace will have to work twice as hard, and you will lose efficiency, costing you more on your electric bill. Likewise, if you have a programmable thermostat, it may also have an option to set a reminder to change your filter. You should take advantage of it!

Thickness matters. If you have a filter thicker than 1 inch, that additional surface area buys you more time before the filter is really dirty. It doesn’t hurt to look at it each month, though you should expect the thicker pleated filters to last longer before needing to be swapped out with a clean filter.

If you’re still feeling a little unsure about when to change your air filters or what kind to use, you can ask a professional who is North American Technician Excellence (NATE) certified. You can also contact your local cooperative’s energy advisor, who can answer questions and provide support about your furnace filter and give additional advice on energy efficiency tips to help you save money.

Maintain your heating and cooling system to ensure that it is ready to work at peak efficiency all year long. For advice on your furnace or other systems in your house, contact your local electric co-op’s energy advisor.