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.
Most single filters packaged for retail are priced very high compared to the low price you can purchase quality 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.
The number one mistake you are likely to make purchasing 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.
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.
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.
|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|
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.
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.
Depending on your HVAC sytems you may have return vent filters or a whole house filter. Vent filters, as pictured above are more straight forward to find the actual size and correct replacement.
The image above is from an Atomic Filters 20x20x1 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.
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.
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.
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.
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.
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 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.
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.
How are you going to Buy You Air Filters?
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Lennox X7935 MERV 16 Furnace Filter Free Shipping Healthy Climate HCC14-16 Air Cleaner $98.95
Experience the ultimate air quality with the Lennox X7935 Air filter.
1 Inch Air Filters also known as Furnace Filters, HVAC Filters, Air Conditioner Filter and AC Filters. Atomic brand filters are made from Quality materials in The USA. Made in the USAFilters are made of synthetic material and pleated for optimal air flow. Air filters with a Nominal Size of 1 inch thick air filters have an actual size of .75 inches. MERV 8 air filters use Mechanical filtering to filter out particulate from the air flow. MERV 11 and MERV 13 air filters use Triboelectric(or electrostatic properties in addition to mechanical means to filter the air flow.
Air Filter Size Chart
No need to go to Home Depot or Walmart for your Honeywell air purifier filters. Atomic Filters can help you find the correct Honeywell replacement filter and save you money with out the hassle of having to fight traffic and hope the box store has your item in stock.
When you are buying your air filter online most important thing to know is Air Filters have two sizes that you need to understand the Nominal size and the Actual Size. Not understanding these numbers often leads to consumers purchasing a filter that does not fit their Furnace or HVAC system.
Not understanding the Nominal Filter Size is the primary culprit for incorrectly purchased filters.The Nominal Size is the usually the dimensions used to Label the filter. For instance 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.
The actual size as you might have guessed are the actual dimensions of the filter by length, width and thickness. This size is often 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 sometime 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 ensure a snug fit.
|Size||Example 1||Example 2|
Furnace filters should fit securely but should not have to be forced into position. If you have to force the filter into its slot, then it is probably too big. Forcing an improper filter size in a filter can cause it to buckle, damaging the filter or reducing its ability to function properly. Filters are a smaller than their slot to allow for easy replacement. Some HVAC units may need a filter with dimensions that are unique or uncommon. In these cases, a custom filter needs to be ordered.