How to Choose the Right Home Air Filter Every Time in 2024

Have You Ever Had Trouble Finding the Right Replacement Furnace Filter?

Nobody loves changing out air filters, but it’s something that has to be done if you want to keep your home healthy and HVAC system happy. The problem is that most homeowners aren’t quite sure how to choose the right filter for their furnace. Do you?

Find Your Filter Easily

You can find the part number or the size on the side of the filter. Filters are measured by Nominal size which is a rounded number that varies by brand so many filters have the part number for each brand they are compatible with listed. The Lennox filter below shows it Part number X0583 and the Honeywell part numbers, FC100A1029 and FC35A1001, that this filter can replace.

Do You Replace Your Filters Enough?

Do you replace your home’s furnace filters enough? Knowing when to change out dirty filters and replace them with clean ones plays an important role in (1) keeping your family safe and healthy and (2) allowing your HVAC system to run at optimal efficiency. Unfortunately, there isn’t a standard answer. When you should replace your filters depends on a number of factors.

One of the first things to consider is the useful life suggested by the furnace filter manufacturer. Most filters clearly recommend how often they need to be replaced – typically ranging from one to six months. At the time of installation, use a marker to write the date. This allows you to come back a few months later and calculate how much life you have remaining on the filters.

When checking the date, it’s also smart to conduct a physical exam of the filter. Does it look extremely dirty, or does it still appear to be in good condition? If you suffer from allergies and/or have pets in the house, you’ll likely need to replace your filter before the manufacturer’s recommended date.

Replacing an air filter is a pretty simple and straightforward process. It’s the cost that causes most people to put off this important home maintenance task. However, consider that the U.S. Department of Energy claims replacing a dirty filter with a clean one can lower HVAC energy consumption by 5 to 10 percent – resulting in significant monthly savings. It also causes your system to work less, which extends its life and prevents costly repair issues down the road.

Air Filter VS Furnace Filter

Air filters and Furnace Filters are the same thing and the are also know as AC filters, Air Conditioner filters and HVAC filters. So a 20x25x4 air filter is the same item as a 20x25x4 furnace filter. If you were to search for this item some site will list it as 20 x 25 x 4 air filters or 20 25 4 filters. These air filters sizes are all the same.

4 Things to Consider When Choosing a New Filter

Air Filter Sizes

Now that you’re aware of the need for changing air filters in your home, let’s move on to the biggest challenge homeowners often have: sorting through the variety of filters available on the market and finding the right one for the right price. There are not really standard size filters, but popular sizes. It is best not to assume you have a standard size filter. Here are a few things you’ll want to consider:

1. Nominal vs. Actual Size

The very first thing you have to figure out is what size furnace filter you need. Typically this is as simple as looking at your current filter and – assuming it fits appropriately – finding the air filter sizes as dimensions on the label. There is, however, some confusion when it comes to ac filter sizes – so let’s touch on that.

Your filter technically has two sizes. The first is the “actual size,” which is the true dimension of the filter. For example, your filter might come out to 19.5x19.5x0.75 inches with a tape measure. However, to simplify the buying process, filter manufacturers round these numbers up to create a “nominal size.” Using the previous example, you would actually need a 20x20x1 air filter.

Complete List of Whole House Brands and Air Conditioner / Furnace Filter Sizes with Actual Size and MERV ratings available

Listed in the chart below are the standard size 1 inch, 2 inch and 4 inch depth air conditioner filters for your AC, Furnace, HVAC at Atomic Filters. Also listed are the whole house air filters collections carried by Atomic Filters. When it comes to a 1 inch vs 2 inch furnace filter you could use a 2 inch filter if your vent is deep enough and a 2 inch filter will generally last longer since it has more media.

Find You Filter by Size or Brand

In addition to carrying major brands of furnace filters like Lennox, Carrier, Trion Air Bear, Honeywell furnace filters and Skuttle we also offer custom size filters at Atomic. Select the size to see a collection of filter for that size or select your Brand and see the entire collection of Whole-house furnace filters available. Need to know more about MERV ratings check out our air filter knowledge page. Filter are usually listed by the Nominal Size which is a rounded number, based off of the true dimensions of the filter which are called the "actual size". If you need a popular air filter size you could search for air filter 20x25x1 or just go to the guide and find your link to see all the 20x25x1 air filter buying options.

Most Popular Air Filter Buying Guides

16x20x1 Air Filters

16x25x1 Air Filters

20x20x1 Air Filters

20x25x1 Air Filters

Furnace Filters

Furnace Filter Sizes

Lennox Air Filters by Size and Model Number

Lennox X6672 HCF16-16 Healthy Climate 16x25x5 Merv 16 Filter

Lennox Furnace Filter 20x25x5

Best Place to Buy Air Filters Online

Find Your Filter by Brand

Click the link for the brand to see the entire collection. Use the search to find your item by Model, Title or Size.

Find Your Furnace Filter by Size

Find the link for a size such as the 20x25x1 air filter and just click the air filter size to the purchase options for the 20x25x1 ac filter sizes.

2. Efficiency Ratings

Once you know what size you need, the second most important thing to consider is the filter’s efficiency. Thankfully, The American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) have developed a standard rating system that the air filter industry follows. Known as MERV, this numbering system allows consumers to compare different brands and filter types against each other and determine how effective different products are in removing airborne particles.

MERV ratings range from 1 to 16, with the higher numbers correlating to smaller filter pores for better filtration of airborne particles. While you may assume that higher ratings are automatically better, this isn’t necessarily true. The smaller the filter pores are, the more resistance to airflow there is. This puts pressure on your system and can ultimately make it inefficient.

The key is to find the highest MERV rated filter that still allows your system to operate at maximum airflow. Most homeowners will find that their systems work best with MERV ratings between 8 and 13.

3. Air Filter Designs

Not all air filters are designed the same. The different features found on various products are intended to provide unique benefits. The biggest difference you’ll notice is pleated vs. non-pleated.

In general, pleated furnace filters are deemed more efficient and durable. They feature more surface area, which theoretically allows them to catch more contaminants and particles while still allowing for maximum airflow. Flat-panel fiberglass filters usually aren’t recommended, unless you’re only worried about cost and very basic protection.

4. Washable vs. Replaceable

The final decision you have to make is whether you want to go with the standard replaceable filters we’ve discussed in this article, or if you’re interested in paying a little more for a washable filter.

Washable filters – as the name suggests – simply need to be rinsed with a garden hose on a monthly basis, air dried, and then put back in place. They’re intended to last for many years and prevent the need for regularly purchasing filters every few months.

The biggest problem with washable filters is that they typically only have a MERV rating of 1 to 4. In other words, they catch the big particles, but aren’t very effective at trapping bacteria, viruses, pet dander, and allergens.

Choosing what kind of filter you want comes down to a simple list of pros and cons. Replaceable filters are more airflow restrictive and require you to buy new filters regularly, but they tend to catch more airborne particles. Washable filters are less restrictive, which means they let more particles into your home, but only need to be replaced every few years.

Super Charge Your Air Filters

You can proactively clean the air and surfaces in your home by adding a UV Air Purifier that creates supercharged particle and produce aerosolized hydrogen peroxide or H2O2. This is the same compound created by thunderstorms and waterfalls in nature and helps purify the air. Aerosolized hyrogen peroxides are effective in reducing bacteria, viruses, odors, and other contaminants that exist in the air you breathe inside your home.This creates charged particles which will attract to other particle in the air for better filtration when using electrostatic filters. Check out UV Air Purifiers

Find out more about how the REME HALO works.

Make Changing Your Air Filters Easy

Once you find the right filter, your goal should be to make it as easy as possible to replace the filter without forgetting. At Atomic Filters, we make the process of replacing your filters simple, easy, and affordable. Simply subscribe to the filter that fits your needs and we’ll deliver a new one when it needs replacing!

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