How To Clean or Replace your Furnace Filter

How To Clean or Replace your Furnace Filter

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It’s fall! That means changing leaves, lower temperatures and furnace maintenance. Wait – what? Furnace maintenance? Yes! As the temperatures start to dip, it’s time to make sure your heater is running in the best condition possible. One of the best ways to do that is to change out your filter. Plus, changing your filter helps to ensure you get coverage on any home warranty plans you have.

Before you start on this DIY maintenance, make sure to go to your furnace owner’s manual to see what kind of filter you need to buy. There are a variety of different shapes and sizes, and the manufacturer will include which size and shape is best for your furnace. Whether your furnace is covered by a manufacturers warranty, or home warranty plan, it’s important to follow manufacturer’s instructions. If you provide proper filter maintenance and your furnace breaks down, your home warranty plan will repair or replace your furnace.

Once you find the manufacture’s specifications on filters, there are a variety of options you can purchase that filter out different levels of dust, viruses and smoke. If you need help deciding what filter to buy for your furnace, Landmark  can show you how to choose a filter for your HVAC system here.

If you can’t find your manufacturer’s specifications on what kind of filter to purchase, you can easily see what size you have already, and buy one based off of that. Finding where your filter is on your furnace shouldn’t be too hard. Here are a few tips:

  1. Turn your thermostat down or your furnace off before doing any maintenance on your furnace. You don’t want it kicking on while you’re changing out the filter, or taking off panels. (If you purchased your home warranty plan through Landmark, your thermostat is also covered)
  2. Determine where your filter is by looking at the ductwork. All furnaces work essentially the same way: Air is brought in from outside, blown through a filter and heated, and then pumped through your home:
  3. How a Furnace Works

  4. You will be able to see ductwork coming into your furnace (bringing cold air in) and then ductwork coming out of your furnace (blowing warm out into your house). Your filter will be between the ductwork bringing air in and the furnace body. 
    Some furnaces have small panels that have a handle that lifts off where the filter sits. Other furnaces have the filter at the bottom of the furnace, and are accessible by removing the front access panels of the furnace. Filter replacements are covered by some home warranty plans. If you need help finding your furnace filter, you can call your home warranty and see if they can set you up with a contractor. This contractor may perform a pre-season tune-up on your furnace and let you know where your filter is located.
  5. After you have located the furnace filter, look to see what kind your furnace already has installed. Most filters have the dimensions on the side. If that filter looks to fit perfectly (and hasn’t been cut to fit) then you should purchase a filter in those same dimensions. Purchasing a filter that is too small or large can result in gaps that let dirt, dust and debris through, which can burn out your furnace. Your home warranty plan’s contractor can also let you know which is best for your furnace.
  6. Find the dimensions of the filter on the side

If you still aren’t sure what kind of filter you should purchase, take note of the brand and the model number (it should be on your furnace’s panel) and ask your local hardware store employee, or your home warranty plan’s contractor.

Once you’ve found your perfect filter, it’s fairly easy to change them, regardless of what type you purchase.

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Changing your HVAC Filter

1. Shut the furnace off or turn the thermostat down.


2. Remove the access panels to get to the filter.

3. Remove the old filter.

4. Insert the new filter.