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How Much is a Filter For a Furnace?
5 Factors That Affect Furnace Filter Prices

Air filter cost isn’t just about who you buy the filter from - there are several considerations that play a role in how much you pay. That makes it hard to understand what you should and could expect to pay for filters in your own home.

Below are five of the top factors that determine furnace filter cost.

Filter Size

Like many products, bigger products translate into higher cost. With filter sizes, the length, width and thickness (also called depth) impact the pricing in different ways.

Let’s look at a few examples from our stock to show how big a difference filter size can make in price (note: prices are current as of 10/2/20. Your mileage may vary when you go to the pages themselves).

Looking at the most extreme example, we can compare our smallest air filter size to our largest:

30 x 36 x 4 air filter
$59.21 for 1 filter

That’s more than triple the price per unit – so, which factor plays the largest role in that price increase.

Here we have two standard 1” thick air filters with the same MERV rating (more on that here). Based on the size differences in length and width alone, that accounts for a $20 difference in the cost of the filters:

30 x 36 x 1 air filter
$38.41 for 1 filter

By contrast, when we compare air conditioner filter cost when the height and width are the same, but the depth is different, the price differential is less severe:

16 x 25 x 1 air filter
$17.51 for 1 filter
16 x 25 x 4 air filter
$25.83 for 1 filter

These three examples highlight how big the air filter cost price range can be depending on the size. While there’s not much you as a customer can do to change that, it does give you an idea of how much you have to pay. It is possible to use a shallower filter in a return vent that can accommodate a deeper one – however, know that you may have to change that air filter more often, which negates some of the cost savings.

Read More: How Often Do You Need to Change My Air Filter

Return Vent vs Whole House Filters

Do you need a whole house air filter or a standard return vent filter? A whole house filter slots into your central heating or air conditioning unit, so that air coming in and going out of the unit is filtered properly. By contrast, the return vent filter fits into a grate in the largest air vents in your home, usually mounted on the wall or ceiling. Whole house is thicker than standard air filters, many of which are just 1” in depth. Most whole house air filters are 3-5” in depth. That difference in size, as discussed above, makes a different in sizing.

Many whole house filters are also brand specific. If you look at our selection of whole house filters, you’ll see there are over three dozen brands to choose from. Those products are also different because they are outfitted with specific parts or frames to make them compatible with that specific brand or furnace or air cleaner. As a result, when comparing a brand-specific filter and a non-specific filter with similar width and length, the price differential is more significant than the example shown above:

16 x 25 x 1 air filter
$17.51 for 1 filter

MERV Rating

Next up is MERV rating, or in other words, how well your air filter purifies the air. MERV rating ranges from 1-20 with 20 being the most proficient at cleaning the air. But that effectiveness comes at a price.

Here again some Filterbuy examples can help illustrate the difference.

Each time you move up the MERV rating the cost to replace an air filter goes up by about $5 per filter. Now let’s see what the furnace filter cost would be if the air filters also aren’t the same size.

What about ratings above MERV 13? That’s when you start getting into the filtration territory of HEPA air filters? Like any increase in filtration capabilities, the price will go up accordingly – because Filterbuy doesn’t carry HEPA filters, we can’t showcase an exact price difference here. Most HVAC systems are also not configured to use HEPA-grade furnace filters, both in a whole house or return vent setup. This is where air purifiers with HEPA filters come in handy – you can get the benefits of that level of filtration without having to rework your home system.

Filter Construction

How well an air filter is constructed will impact the price. The biggest filter construction consideration is the filter material (also called filter media) itself. The two most common materials are fiberglass or pleated. Fiberglass filters are made with strings of nonbiodegradable fiberglass that are woven together, while pleated air filters are made with either polyester, cotton or paper sheets that are layered and pleated together.

Generally speaking, pleated filters will cost more if all the other factors are the same. Pleated air filters are simply more efficient and better constructed. Because of this, they tend to last longer. That means even though a pleated filter costs more at the time of purchase, the air filter replacement cost is lower over time.

Read More: Fiberglass vs Pleated Air Filters

Filter media treatments can enhance performance but may also increase the price. Electrostatic air filters activated carbon air filters, and odor reduction filters will all cost more than a standard filter of the same size, but the added media treatment could be worth the higher price tag.

Finally, the frame of the filter will impact the price as well. While most home air filters are made with a cardboard material, not all cardboard frame is created equal. Filterbuy’s frames, for example, use a stronger beverage board material for the filters so that the frames don’t bend and break unexpectedly. That’s crucial for air filters used in a commercial context or in buildings with higher levels of humidity.

Some commercial air filters will come in a metal casing, and those will be more expensive than the traditional frame material.

Purchase Behavior

As Costco has taught us all, buying in bulk can cut down on your costs when buying things for our homes, and air filters are no exception. The more air filters you buy at once, the cheaper each one will be.

Let’s look once again at the previous example, 20 x 20 x 4 air filter with MERV 8 rating. Here’s how the price per filter breaks down by the number of filters being purchased. As you can see, the price per unit is almost 50% lower when you buy in the largest quantity:

QuantityPrice per Filter
1$25.83 ea.
2$16.64 ea.
3$15.19 ea.
4-5$14.72 ea.
6-11$14.15 ea.
12+$13.29 ea.

That cost benefit compounds when you order filters of a larger size or MERV rating. Check out what happens when we upgrade to a 20 x 20 x 4 air filter with MERV 13 rating.

QuantityPrice per Filter
1$33.43 ea.
2$20.89 ea.
3$19.94 ea.
4-5$19.47 ea.
6-11$18.90 ea.
12+$18.04 ea.

And here’s how the discount breaks out for another MERV 13 air filter in a smaller size (8 x 14 x 4):

QuantityPrice per Filter
1$28.79 ea.
2$17.99 ea.
3$16.99 ea.
4-5$16.49 ea.
6-11$15.89 ea.
12+$14.99 ea.

Another way to save is by joining an air filter subscription service. The Filterbuy subscription service automatically delivers an air filter every three months for an additional 5% discount.

Using our cost-saving measures and quality product, we can help you get the best quality air filter for the money. Come find your new air filter with us!