This One Simple Thing Could Help Your Furnace Last Longer

Cleaning and replacing your furnace filter regularly could extend the life of your furnace by years.

Erin Gobler Contributor
Erin Gobler is a personal finance writer based in Madison, Wisconsin. She writes about topics including budgeting, student loans, credit, mortgages, investing and insurance. Her work has been published in financial publications and startups such as NextAdvisor, The Simple Dollar, LendingTree, Robinhood and more.
Erin Gobler
4 min read
a dirty furnace filter

Do you clean or replace your furnace filter regularly? 

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Homeownership comes with what feels like a never-ending to-do list. One important task on that list is ensuring your heating and cooling system is properly maintained. You should be replacing your furnace's air filter on a regular basis to keep your HVAC system working properly and ensure your family has good air quality in your home. Keep reading to learn how furnace filters work, how often you should replace yours, what type of filter to get and more.

Read more: Furnace Buying Guide: Find the Best Furnace for Your Home

How furnace filters work

Before we talk about replacing your furnace filter, let's talk about the purpose these filters serve and how they work. The job of a furnace filter is to trap contaminants from escaping through your home's heating and cooling system.

There are two reasons it's important to filter out these contaminants. First, a good furnace filter will keep the air in your home cleaner by trapping any airborne contaminants. This is especially important for anyone with allergies or asthma, as the filter helps remove pollen, dust and other allergens.

The other reason the filter exists is to protect your HVAC system. Without a filter, dirt and other debris can accumulate in your heating and cooling system, affecting your energy bill and requiring you to replace your HVAC system sooner.

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How often to replace a furnace filter

As you can tell, your furnace filter serves an important job in your home. As a result, it's important to replace it on a regular basis to ensure it can continue to do its job well.

So how often should you replace your air filter? That depends on a few factors. First, how often you replace your filter depends on the thickness of your air filter. Most filters should be replaced every three months. For thicker filters, you may be able to extend that by several months. If you aren't sure, check the manufacturer's recommendation for the specific filter you've purchased.

But the thickness of your air filter isn't the only factor to consider. For example, if you have someone in your home with allergies or asthma who requires better indoor air quality, you may want to replace your filter more often. 

Additionally, if you have pets at home creating fur or dander, or a large family to bring in more contaminants, you may also wish to replace your filter more often. On the other hand, if the home is primarily a vacation home that isn't used often, you may be able to extend the amount of time before you replace the filter.

Finding the right filter for your furnace

When you replace your air filter, it's important that you find the right filter for your home. Not all filters are created equally, and your heating and cooling system may require a certain type.

First, be sure to buy the right size filter for your HVAC system. Common filter sizes are 16x20, 16x25 or 20x25 inches. You can check the filter you currently have to see what size it is.

In addition to choosing the right size, you'll also have to decide what type of filter you want. There are several different types, each of which has different advantages. The most common type of filter is fiberglass -- this type of filter is often about an inch thick and catches large contaminants. It may not be sufficient if you have someone in your home with asthma or allergies, since it can fail to trap smaller contaminants.

Other types of filters include:

  • Disposable pleated: This type of filter is made of cotton or polyester, is able to catch small particles, and is the most affordable. This type of filter should be changed more often.
  • Disposable electrostatic: Made of self-charging electrostatic paper or cotton fibers, this type of filter can trap small harmful particles. This type of filter is slightly more expensive than the disposable pleated but less expensive than some of the higher quality filters below.
  • Permanent electrostatic: This type of filter is similar to the disposable electrostatic one, but is permanent. You can remove it and clean it, or even wash it in the washing machine. They are more expensive but don't need to be replaced, saving you money in the long run.
  • High-efficiency pleated: This type of filter is thicker than many others, often up to four or five inches. This type of filter can trap the smallest particles, creating the best air quality. This type of filter is more expensive and can't be used with all filters.

How to change a furnace filter

Now that we've talked about how often to replace your air filter and what type to get, let's talk about how to go about replacing your filter. Here's an easy step-by-step guide to replacing your air filter:

1. Turn off your furnace. 

2. Locate your filter compartment and remove the door or service panel.

3. Slide the old filter out.

4. Slide the new filter in.

5. Turn your furnace back on.

The bottom line

Your furnace's air filter is an important part of ensuring you have good air quality in your home and extending the life of your HVAC system. They're easy to replace, but it's critical that you replace them on a regular basis and buy the right type of filter for your furnace. If you have questions about your furnace or aren't sure where to start with replacing your filter, be sure to contact a qualified professional for help.

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