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9 Tips to Buy Your Air Filters Online and Avoid Costly Mistakes in 2024

#1 Buying Single Filters Can End Up Costing You Almost Twice as Much as Buying in Bulk

It can be fun to go to Lowes or Home Depot Saturday morning and work on a project for your home, but it is probably not the best place to buy air filters.  You need to replace your filters on a regular basis to protect your HVAC equipment and to protect your home’s air quality. You do not need to buy cheap air filters to save money when you buy your air filters online. You can get a high quality furnace filter online for a fraction of the price you would spend for a filter at Walmart, Lowes or Home Depot and your furnace filters will be delivered to your doorstep when you buy filters online.  

Buy Air Filters in Bulk and Save Money

Most single filters packaged for retail are priced very high compared to the low price you can purchase quality air filters in bulk. For instance, a single 20x20x1 Filtrete 1500 Ultra Allergen Filter which is the equivalent of the Atomic 20x20x1 MERV 13 Allergy Elite Pleated Air Filter, sells at a premium around $17.87. In Comparison, the Atomic Brand 20x20x1 air filters which are sold in bulk as a case of 6 sells for $54.99 or $9.08 per filter. So buying bulk air filters online can save you a significant amount when you choose to purchase your HVAC filters online.

Where is the Best Place to Buy Air Filters Online for the best Price

When it is time to make your filter buy, whether you are looking for the best place to buy air filters or searching for cheap air filters, you do not have to sacrifice quality. Here is a simple process you can use.

Look for a company that has great reviews

Many companies now sell Air Filters on multiple channels including there website, Amazon and eBay. You can check reviews not only on the company website but also Amazon and eBay.

Buying Air Filters Direct on the Company Website to Save the most on Air Filters

Buying directly on the company website will usually get you the cheapest price for air filters since they company does not have to pay a commission to Amazon or eBay. 

But Compatibles to Save Money

If you need a special Whole House filter for a Carrier, Lennox or Honeywell system, consider buying a compatible to save money. Sometimes the compatibles for these filters can be half the price of the OEM furnace filter prices.

Atomic Filters has some of the highest quality and most competitive pricing for purchasing air filters online. is a good place to start looking for air filters for your furnace or HVAC system.

Amazon is a good place to research your item and check seller reviews. If you buy on Amazon it is a trusted market place where you can find competitive pricing.  

eBay is a good place to research your item and check seller reviews. If you buy on ebay, it is a trusted market place where you can find competitive pricing on and deals on air filters.  


# 2 Avoid The Most Common Mistake Buying the Wrong Filter: Nominal VS Actual Size

 The number one mistake you are likely to make purchasing air filters online is purchasing the wrong size filter. This is a big hassle because you have to send back the incorrect filter, which may be a different price than the filter you needed, and could even cost you return shipping. You may need to wait for a refund and/or repurchase the correct filter. Understanding filter sizing can save you both time and money when buying air filters online.

How to get the right furnace filter size- actual size and nominal size explained

Best 20x20x1 Air Filter for Allergies

Buy 20x20x1 MERV 8 Furnace Filters Now

Nominal Filter Size is the main culprit for incorrectly purchased filters. The Nominal Size is the dimensions used to Label the filter, but are usually rounded numbers and not the actual size of the filter. For instance, a filter's nominal size may be 16x20x1. These dimensions are a rounded value on the filters actual measurements. The actual measurements on this filter may be 15.5x19.5x.75, but that could vary by brand and manufacturer. So in order to make sure you have the correct size filter, especially if you are replacing with a different brand it is important to confirm the actual size on the filter. When purchasing filters on the internet, the Nominal size is usually found in the product title. When you search for a filter most people search for the nominal size. So you may enter furnace filter 20x25x1 or 20x25x4 furnace filter or even 20 25 1 air filter but you must check the actual size to make sure it is also a match for your house air filters.

Most Popular AC Filter Sizes

The most common AC filter sizes and furnace filter sizes are the 16x20x1 air filter, 20x20x1 air filter, the 16x25x1 air filter and the furnace filter 20x25x1. All of these ac filter sizes can be found in the air filter size chart. The chart is a furnace filter size finder just click on the filter sizes and you will see purchase options. Click on the air filter 16x20x1 to see merv 8 filters, merv 11 filters and merv 13 filters available in the ac filter sizes.

1” vs 2” air filters

Some people wonder is a 2 inch filter better than a 1 inch air filter? Well when is comes to 1 inch vs 2 inch furnace filters you should use the filter your system is designed to use. A 1 inch AC filter may have to be changed more frequently but will so the same job. Deeper pleated filters can last longer because they have more media. So the same would go for 4 inch vs 1 inch furnace filters. A 4 inch furnace filter will last a longer time than a 1 inch. The return grill space or the furnace must be designed to have the deeper filter to be used. Many commercial spaces use 2 inch filters or 4 inch filters to help reduce maintenance cost of replacing filter. From a filtration stand point a 20x25x1 air filter merv 13 and a 20x25x4 MERV 13 furnace filter will both have the same performance of filtration. 

Most Popular 1 inch Air Filters

Most Popular 4 inch Air Filters

Actual Filter Size: Making the Correct Replacement Filter Purchase

The actual size, as you may have guessed, is the actual dimensions of the filter by length, width and thickness. This size is usually on the filter right below the Nominal size and is usually labeled as the actual size. When you are buying a filter online the actual size is sometimes in the product bullet point or the product description. If your filter does not have actual dimensions on the outside of the filter, you can measure you filter to get the correct dimensions. Some brands have a foam gasket on the outside of the filter, in this case you will want to make sure you have a compatible actual size and that it also has the foam to insure a snug fit. Check to see if the filter list compatible brands and model numbers. These are usually in the filter descriptions and bullets of the filter detail page. On Amazon you can usually find this information farther down the product page below the fold or click the link for additional product details.

Related Filter Buying Guides: Popular Size Air Filters

16x20x1 Air Filters

16x25x1 Air Filters

20x20x1 Air Filters

20x25x1 Air Filters

Furnace Filters

Super Charge Your Air Quality With the iWave Air Purifier

You can proactively clean the air and surfaces in your home by adding an In Duct Air Purifier that creates supercharged particles. This is the same compound created by thunderstorms and waterfalls in nature and helps purify the air. Aerosolized ions 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 the Iwave-R. Learn more about how these air purifiers work to purifier the air and surfaces in your home. 


Furnace Filter Size Chart: The Best Place to Buy Air Filters

Find Your Filter Sizes Easy in 1" Deep Filters , 2" Deep Filters, 4" Deep Filters See the Complete list of Furnace filters by Size, MERV Rating, and Brand.

Furnace Filter Size (Nominal) Actual Size
10x10x1 9.5 x 9.5 x .75
10x20x1 9.5 x 19.5 x .75
10x24x1 9.5 x 23.5 x .75
10x30x1 9.5 x 29.5 x .75
12x12x1 11.75 x 11.75 x .75
12x16x1 11.5 x 15.5 x .75
12x18x1 11.5 x 17.5 x .75
12x20x1 11.5 x 19.5 x .75
12x24x1 11.375 x 23.375 x .75
12x25x1 11.5 x 24.5 x .75
12x30x1 11.625 x 29.5 x .75
12x36x1 11.5 x 35.5 x .75
14x14x1 13.5 x 13.5 x .75
14x15.5x.75 14 x 15.5 x .75
14x18x1 13.5 x 17.5 x .75
14x20x1 13.5 x 19.5 x .75
14x24x1 13.375 x 23.375 x .75
14x25x1 13.5 x 24.5 x .75
14x30x1 13.5 x 29.5 x .75
15x20x1 14.5 x 19.5 x .75
15x25x1 14.5 x 24.5 x .75
16x16x1 15.75 x 15.75 x .75
16x18x1 15.5 x 17.5 x .75
16x20x1 15.5 x 19.5 x .75
16x24x1 15.375 x 23.375 x .75
16x25x1 15.5 x 24.5 x .75
16x30x1 15.5 x 29.5 x .75
16x32x1 15.5 x 31.5 x .75
17x22x1 16.5 x 19.5 x .75
18x18x1 17.5 x 17.5 x .75
18x20x1 17.5 x 19.5 x .75
18x22x1 17.5 x 21.5 x .75
18x24x1 17.375 x 23.375 x .75
18x25x1 17.5 x 24.5 x .75
18x30x1 17.5 x 29.5 x .75
20x20x1 19.5 x 19.5 x .75
20x21.5x.75 20 x 21.5 x .75
20x21x1 19.5 x 20.5 x .75
20x22x1 19.5 x 21.5 x .75
20x24x1 19.375 x 23.375 x .75
20x25x1 19.5 x 24.5 x .75
20x30x1 19.5 x 29.5 x .75
21.5x23.25x.75 21.5 x 23.25 x .75
22x22x1 21.5 x 21.5 x .75
24x24x1 23.375  x  23.375  x  .75
24x30x1 23.5 x 29.5 x .75
25x25x1 24.5 x 24.5 x .75
30x30x1 29.5 x 29.5 x .75
30x36x1 29.5 x 35.5 x .75

# 3 The Most Costly Mistake, Using The Wrong Filter: How To Get the Right Filter?

Find the Right Filter for Your System? An Explanation of MERV

When considering the air quality in your home, you should consider an air filter with highest level of efficiency that is compatible with your HVAC system. Minimum efficiency reporting value, known as the MERV rating, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters.

MERV Ratings Explained

 How to Compare Filters

Comparing MERV ratings is a good way to begin to comparing filters. A Pleated filter with a rating of at least MERV 8 is better for airflow which is going to help your HVAC system operate more efficiently while still protecting your air quality.  Home Air Filters have MERV ratings that range from 0 to 16. Most new homes can support an air filter with a MERV rating from 8 to 13 filters, but MERV 15 and 16 filters require a system that can support the necessary air flow.

Find Your Filter Brand and Model Number

Depending on your HVAC sytems you may have return vent filters or a whole house filter. Vent filters, as the 20x20x1 air filter pictured are more straight forward to find the actual size and correct replacement.

Buying the right 20x20x1 Air filter Atomic

The image above is from an Atomic Filters 20x20x1 Furnace Filter MERV 13 product listing. In addition to the filter having the Nominal size and actual size on the product image, the product title list the nominal size. The actual size for the filter is listed in the bullet points. Once you know what information to look for, making the purchase decision straight forward. 

Whole house furnace filters often have compatible models across brands, but you need to insure that the replacement filter is compatible with your systems filter.This is best done by checking the product description to make sure your current filter model is listed.

Find The Right Whole House Furnace Filter by Model number and brand

 You can usually find the proper replacement filter model  in your HVAC user manual. In the Amazon listing pictured for this Lennox Filter, you can see all of the information you would need to make the correct purchase.

#1 Shows the Nominal Size of the Filter in product title along with the Brand.

#2 Shows the Lennox Model number X6673 for this furnace filter.

#3 shows other brands compatible model numbers this filter can replace.

 #4 shows additional details on the filter including the actual size of the filter. 

Find Your Filter Easily

Enter The Filter Part Number or Size from Your Current Filter in the Search, for example, enter X8795 or 16x25x5.


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. 

Furnace Filter Part number


# 4 Consequences of The Wrong Filter for Your System

Using the wrong air filter over time could end up damaging the heating and cooling system itself. By reducing your systems efficiency, you could notice higher utility bills. When you use the wrong size air filter, or you install it incorrectly, the filter can’t effectively prevent dust from accumulating on the system’s coils motors and blowers. You’ll end up with a dirty furnace that can’t properly perform, and all of that debris could end up harming the system’s internal components.

Find the Best Quality Home Air Filter for Your System 

While you may think that using a more efficient filter with a MERV rating from 15 to 16 would be the smart option for allergy suffers and improved air quality, not every system is designed to work with these highly rated filters. If your system isn’t compatible, these filters will drastically restrict airflow. You can still have a high-efficiency filter, but make sure it’s one that is designed to work with your HVAC system.

You can still have a high-efficiency filter, but make sure it’s one that is designed to work with your HVAC system.

Using an air filter with too high of a MERV for your system can have similar effect of a clogged air filter, if a filter becomes clogged, airflow will be reduced, which causes the fan motor to work harder. This means more energy is used, which will increase your utility bill. Eventually the fan motor can burn out, resulting in overheating and failure of the entire system. Overheating can cause a heat build up around the heat exchanger in the winter which can cause the heat exchanger to crack. A cracked heat exchanger is a serious issue and needs to be replaced immediately to prevent system failure, fire or the release of carbon monoxide gas into the home.

Dirty Air Filters Can Cost You Dollars

Having Dirty filters can allow components within the HVAC system to get dirty. This causes problems such as dust and debris on cooling coils, which can lead to freezing on the evaporator coils. Frozen coils block airflow, reducing the system’s ability to maintain indoor climate control which causes the system to work harder with less efficiency increasing your energy bill. Left unchecked, the system will fail and requiring a costly replacement.

Dirty Air Filters can cost you money

Dirt in The Duct Work- Dirt in Your Air

Dirty air filters can lead to excess dirt that will end up in your ductwork, and you’ll need to have the ducts cleaned more frequently. Dirty ducts compromise air quality and some of the dirt can end up back in the HVAC system.

#5 Consider a Subscription and Save When You Buy Air Filters Online and Get the Right Filter Every Time

Once you find the right air filter for your systems, consider getting a subscription and make it automatic. This will ensure your HVAC system is always protected from the most preventable causes of failure and you will have one less thing to remember. Companies often offer a discount on subscriptions saving you even more money.  

Companies often offer a discounts on subscriptions saving you even more money.  

#6 My Order Went to the Wrong Address: Avoid Not Keeping Shipping Addresses up to date for Stored Payments: Apple Pay, Amazon, PayPal, Shop Pay, Google Pay

It is easier than ever to Securely purchase items on line then ever before in History. We have many options to use such as Apple pay where we can make a purchase and check out right on our phones with out having to enter any information. Apple Pay and other payments providers allow you to use stored payment information and stored shipping addresses. Although this is very convenient, it can sometimes lead to having the wrong shipping address on orders if we do not keep that information updated when we move. America is a much more transient population than a generation ago, so if you have moved recently make sure to update all of you payment account shipping addresses before using them to place orders online. 

#7 Track Your Order: If you do not receive Your Order in 7 to 10 days contact the Seller

You will usually get a notice when your order is placed, when it ships and when it is delivered. We place so many orders online it is often hard to keep track of everything. With our emails so cluttered, we can easily miss these notifications. Although most orders arrive in 2 to 6 days anywhere in the county, sometimes weather and other factors can also cause delays. Generally if you have not received your filters in 7 to 10 days, it is time to call or email to check on your order. The item may have been misdelivered or lost by the delivery service. The sooner you can check on it the better. Many delivery services such as Fedex and UPS have a time limit on when they can run a trace or enter a claim.

#8 Check Your Items as soon as they arrive: Wrong Part Received

Often times, we order air filters ahead of time to always have a backup when it is time to replace the filter. Many filter company's have had supply chain issues making it hard to finds certain filters so it is a good idea to have your filters before you need them. With many filters having similar items numbers it can be easily to order the wrong part. Since many companys have time limits on returns, it is a good idea to check the items part number as soon as it arrives, but do not open the item if it is factory sealed, this could void your return.


#9 Open Items: Void return rights

It is best to check the item number before opening any sealed parts. Many part numbers are very similar and ordering mistakes happen frequently. Opening the item or writing an installation day on an item may void the return rights as the item can no longer be sold as new even if it was not used. You would not accept a filter that had writing on it or was not in the manufacturer writing if it was supposed to be new, would you?

This can usually be avoided by double checking the item before you order, but occasionally the wrong item may also be sent, so it is a good idea to double check all of the number before ripping open factory packaging such as sealed plastic shrink wrap on an item or writing an installation date on the side of a filter.

So now that you know best place to buy air filters and how to get the right filter,

How are you going to Buy You Air Filters?


Air Filters Home: FAQ

When looking for the correct home air filter here are several questions you might have.

1. What are the Best home air filters?

The best home air filters is a relative question. You should get the highest MERV rated filter your HVAC system will support it you want the best air quality in your home. Newer Modern HVAC systems should all support at least a pleated MERV 8 rated filter which is around the minimum level you would want to protect your homes air quality. MERV 11 to 13 filters is recommended for allergy sufferers. Superior systems from Carrier and Lennox offer some of the best residential filters available at MERV 15 and 16 respectively.  

2. What do air filters do in a house?

The primary function of an air filters is to protect your HVAC equipment from damage that can occur from dust and debris accumulating on the coils.This can have an effect on the efficiency of your system causing higher energy bills and a shorter system life.

Newer systems air filters are not just focused on protecting the equipment but improving the air quality in your home which is one of the number one health concerns listed by the EPA, CDC and American Lung Association.

3. How Often do you change air filters in your home?

How often you change your home air filters depends on the type of air filter you have in your house and environmental conditions such as smoke, dust or construction. 

Generally here are some guides but it can vary by manufacturer.

1 inch flat air filter - change every 30 days

1 inch pleated air filter- change every 2 to 3 months

Whole house filters - change 6 to 12 months ( more frequent change for desert areas and High humidity tropical areas).

4. How much is an air filter for a house?

Cost on filters may depend on the size of the filters but here are some ballpark prices.

1 inch flat green fiberglass filters which are considered cheap air filters can cost less than $1 but may have no MERV rating meaning they do not protect the air quality.

1 inches pleated MERV 8 filters can be as little as $4.50 if bought in bulk such as a case of 6 filters but the cost is dependent on the size of the filter.

Whole House filters vary in price by manufacture and can range from $25 to well over $100.

Find Your Filter Easily

Enter The Filter Part Number or Size from Your Current Filter in the Search, for example, enter X8795 or 16x25x5.


Related Links

Buy Air Filters in Bulk

Best Place to Buy Air Filters Online

16x25x1 Air Filter

16x20x1 Air Filter

20x20x1 Air Filter

20x25x1 Air Filters

Lennox Air Filters by Size and Model Number

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

Nominal VS Actual Size: Find the Right Furnace Filter Sizes

How to Choose The Right Home Air Filter Everytime

Buy Whole House Air Filters

Buy a Replacement Air Purifier

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