How Often Should You Replace a Furnace Filter

Too many of us are guilty of recognizing that yes, our furnace filters do need to be replaced, but we never take the initiative to actually change them. After all, if your furnace is in good repair and maintaining an optimal temperature in your home, do they really need to be changed? The truth is that if you’re wondering about when you last changed out your furnace filters and can’t remember exactly when that was, it’s likely time for a change.

The Role of Furnace Filters in Your Home

Consider your home’s furnace filters to be like a tool of your HVAC unit, protecting your air quality from all the debris and dust that would otherwise circulate throughout your home. Air filter or furnace filter, they both really mean the same thing. The work that your filters do is key to purifying your home’s air, so ensuring that they’re regularly replaced and therefore clean is a key component of maintaining the health of your HVAC system, and consequently the health of every member of your household.

How long can a filter last?

The lifespan of your furnace filter is dependent on the type of furnace filters or air filters you have. There are filters you can purchase that are reusable, i.e., they can be washed and reused, or you can change out your previous filters with fresh ones as the recommendations stated on your manufacturers’ owner manual. Take into account the individual lifespan of that furnace filter plus other considerations of your home, like family allergies, candle use, and the presence of shedding pets.

The thinner the filter, the more it will need to be replaced. A one-inch furnace filter has a lifespan of up to three months, whereas a three to four-inch filter may have a lifespan of up to nine months. Thicker, five to six-inch filters may live up to twelve months. It’s a lot easier to breathe when you pay attention to the lifespan of your filters and change accordingly!

How often do I need to change my furnace air filter?

Again, the answer to this question is hugely dependent on the type of furnace filter being used. You may still have the box that your filters are contained in, where the filter’s manufacturer will offer the recommended replacement frequency. Of course, you may need to up the frequency with which you replace it if you live in a dusty home, home with smokers, have allergies, or you have shedding pets. Here is the average filter change based on size:

  • 1 to 2-inch filters will need to be replaced every 1 to 3 months.
  • 3 to 4-inch filters will need to be replaced every 6 to 9 months.
  • 5 to 6-inch filters will need to be replaced every 9 to 12 months.

Your furnace filters play an ultimately crucial role in your home’s indoor air quality and HVAC system. When there is a dirty air filter trying to ventilate the air in your home, there is a large risk that your energy costs, the health of your household, and the efficiency of your HVAC system will be compromised. Your HVAC system will have to work much harder and more frequently to push out air with a dirty filter.

Do you really need to change your furnace filter every 3 months?

The “three month” rule is sort of a misnomer depending on the type of furnace filters you have. If you have your standard 1 to 2-inch filters, then yes - you will likely need to change your furnace filter every 1-3 months. Failing to do so can cause a number of safety concerns to arise, such as clogging, overheating, short cycling (which can cause your furnace to turn off when you need it the most) and even fire! Dirty filters have been the cause of residential fires before.

A furnace filter’s main goal, to trap airborne contaminants like hair, debris, and dust, is compromised when it’s too dirty to function.

Signs Your Air Filter Needs Replacing

Your furnace filters may be small, but they play a vital role in your HVAC’s overall performance! One of the first steps in HVAC troubleshooting is typically to replace a dirty furnace filter, so by being proactive you can afford an unnecessary tech call. You may notice any of the following signs if your furnace filter needs to be replaced:

  • A jump in your heating and cooling bills with no change in usage
  • There’s a strange smell or possibly a burning smell in your home
  • You notice a lot of flying dust, debris, and hair - more than usual
  • Your furnace is running for unusually long periods of time, but there’s less heat

If you’re noticing any of these symptoms, it could be time to take a look at your filter. If the filter has turned gray and is covered with lint and dust, then that furnace filter is probably overdue for a replacement.

Note: to replace your filter properly, pay attention to the arrow on the cardboard sides of the filter. The arrow should point toward the furnace, opposite of the return duct. Take note of the direction of the filter before you remove it, to ensure the new one is placed the right way. You may also wish to mark your new filter with the date you replaced it, just to keep track of when that one will also be due for a replacement. Always make sure you put your furnace filter in the right way to avoid collecting unnecessary debris and dust!

Are you overdue on your furnace maintenance tasks like replacing your air filter? If so, the team at ClimateAir can help! Our certified technician team is available 24/7/365 days a year including after-hours, weekends, and holidays at no additional cost to you–ever!

Book your maintenance appointment with ClimateAir over the phone or through our online booking system!