How to install a furnace filter with simple instructions

Changing a furnace filter is a simple home maintenance activity with numerous benefits. Install a furnace filter to reduce your energy bills, clean your air, and keep your home cleaner.

Simply changing your home’s air filter has been shown to improve your energy bills up to 15%!

You should consider changing your home’s furnace filter every 90 days as a general rule. Consider changing your filter sooner if you have pets or allergies.

So how do you install a furnace filter? Check out these simple instructions.

How to Install A Furnace Filter with Simple Instructions

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Step 1 – Turn your furnace off

Locate your thermostat. Turn the system to off and confirm the fan isn’t running. You shouldn’t hear any noise coming from your furnace.

Step 2 – Open the filter housing

Locate your filter housing

The filter housing is often located in your garage. Easily remove the filter housing by giving it a slight pull. Some filter housings might have clips to move aside before you can remove the housing cover.

Note: Sometimes it’s best to inspect your furnace filter between scheduled changes for dirt. Consider change your furnace filter if you’re home becomes dirty or you experience any other symptoms of a dirty filter.

How to choose a new furnace filter

Find your furnace filter size

You should be able to find your filter size by checking the old filter.  Filters have two sizes you need to pay attention to, nominal and actual.

Insert new home air filter

The filter pictured above is a 16″ x 25″ x 4″ which is the nominal size. However, this filter has an actual size of 15.5″ x 24.5″ x 3-5/8″. The actual size is the actual dimensions of the filter.

Determine filter effectiveness with MERV ratings

Next, you’ll need to know what filter works best for your family. You’ll need to know which MERV rating works best for your filtration needs. MERV values for home use typically range from 1 to 13, where 13 is a higher filtration level.


I don’t recommend under a MERV 8 and the price difference isn’t much between MERV 6 and MERV 12 filters. MERV 6 filters are ok for dust, lint, and pollen while MERV 8 filters help filter mold and dust mites.

For most families, MERV 11 or 12 filters are the best option for price and effectiveness.

I own pets, so a MERV 11 or higher is best for my situation. If you live in a large city or have allergies, a MERV 13 might be your best option.

Order your filter

Next, go to Nordic Pure. Look in the upper left hand corner of the website for a place to enter your filter size. Enter in your filter size and search for your filter.

Select filter size

Does the actual filter size match your filter? If it does, select view details.

Confirm actual filter size

You’ll be brought to the Nordic Pure order screen where you should have a few options to choose from.

Nordic pure order screen

Most people will be perfectly ok with selecting a pleated media type. If you want more odor control, select either a pleated and carbon filter or pure baking soda filter. Personally, I do pleated.

Next, select your performance rating depending on the MERV value your family needs. I generally select MERV 12. Nordic Pure offers  MERV 7 through Merv 15!

Finally, choose how many you want to purchase and hit add to cart.

Which is the best furnace filter?

Price is fairly consistent between MERV 7 through MERV 12 filters. However, there is a significant price jump above MERV 12.

Note the price doesn’t change much between MERV 7 to MERV 12. However, the price jumps significantly the higher MERV rating at 13 and above.

Therefore, I recommend sticking with a MERV 12 filter for performance and cost-effectiveness.

Read More: Which home air filters are the best?

Step 3 – Install a furnace filter

Next, insert your furnace filter paying attention to the flow direction arrow. The arrow should point with the direction of flow to ensure proper installation.

So how do you know which direction the flow is going?

How do you know which way to insert the filter if you don’t know the direction the flow is going? There are a few simple ways to tell.

  1. Point the flow direction arrow towards the fan/blower. The filter should be installed at the intake of the fan or blower. This is to protect the fan from contaminants which can damage the fan.
  2. Point the flow direction arrow into the wall or ceiling. If your filter housing is inside your house on a wall or ceiling, then the filter must point into the wall or ceiling.
  3. Turn the fan back on feel which way the air is flowing. If you still can’t tell which way the air is flowing then you can turn the system on briefly to feel the air.
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What happens if you install a furnace filter backwards?

It is not recommended to install your furnace filter backwards. However, you should be ok if you accidentally install your filter backwards from time to time.

A backwards filter will not filter as effective as a properly installed filter. You will also increase the demand on your fan or blower which can lead to increased energy bills. In addition, increased demand can reduce the life expectancy of your fan or blower which can be a costly repair.

Step 4 – Write the date on the filter

Your filter should be replaced once every 90 days for most families. Families with pets or allergy sufferers should install a furnace filter every 30-60 days. To help keep track, write the date on your furnace filter:

Write date on clean air filter

You can also set a reminder on your phone to notify you when it’s time to replace your furnace filter. I set a 90 day reminder on my phone because I don’t always remember!

Air filter reminder

Step 5 – Replace the filter housing cover and turn the system on

Finally, replace the filter housing cover and turn the system back on. Your filter should be good to go!

Video examples on replacing your home’s furnace filter

Filter replace inside your home

Expertvillage created a great video showing you how to properly change an air filter located inside your home, at the return duct.

See it on YouTube

Remember to point your flow direction arrow toward the wall!

Filter replaced at a central unit (inside your garage)

888 Heating and Air Conditioning put together a video that shows you how to replace a home air filter located at your central unit.

See it on YouTube

What’s next?

Check out these simple ways to improve your home’s air quality. Leave a comment below and share this article if you liked it!

John is the founder of TightFist Finance and an expert in the field of personal finance. John has studied personal finance for over 10 years and has used his knowledge to pay down debt, grow his investment portfolio, and launch a financial based business. He is committed to sharing content related to personal finance based on his experience in his career, investing, and path towards reaching financial independence.