Air filters come in thousands of sizes, yet you can never find the one you need at the store. Home air filters are pretty standard items. Size and MERV rating are two of the few variations. Here’s what you really need to know about your whole house air filters.
Why do I need such a big air filter?
You may have heard them called whole house air purifiers, which is a misnomer. An air purifier is an addition to your HVAC system, not part of it. Although these filters do indeed clean the air, they are part of your system and not optional. Now that we've clarified that, let's get back to it.
With the concept of only one filter per home, it is easy to understand why everyone should have a whole house filter. This would be for any person who has more than one air handler in their HVAC system set up at all times.
What does it look like?
In most cases, the whole house air filter will look similar to the standard 1 & 2 inch pleated filters, but whole house filters offer significantly more surface area because of the v-pleats that are deep and fill up it’s thick frame. The most common whole house filters, often referred to as box filters, are 4 & 5 inches thick. With all filters, the “nominal size” of an air filter means that this is how big it would be if there were no curves or bends. There's a standard undercut on one-inch filters, meaning that these measure ¼" to ½" smaller than their nominal size; but with whole house filters, there isn't any kind of undercutting and they are always just what you order from your supplier. Know the exact size air filter you need before ordering, if you have any questions you can contact us here, or check out our air filter size guide.
How is a Whole House Air Filter Different?
Aside from the different physical appearance, a whole house filter has longer longevity than standard 1 and 2 inch filters. A whole house air filter does not need to be changed as often due to it’s large surface area. In most cases, you will want to change these filters every 6 months instead of every 1 to 3 months like standards air filters. In some cases, you may be able to make it a year before changing it out. Like the standard filters, there are things such as location, pets, number of people in the home, allergies, and other contributing factors to consider.
Do Whole Home Air Filters Cost More?
Yes, on average whole house air filters will start around $25 and commonly range to $40+. Since you’ll likely change them less frequently you are likely to save or spend about the same as regular standard air filters.
Where Does it Go?
If you’ve never used a whole house air filter before the location of where it goes may surprise you. Directly in front of your HVAC is some ductwork — whole house filters go directly into that ductwork. Some have a cartridge or housing they fit in before being installed, other setups will allow for the filter to be inserted directly into a slot in the duct.
The Last Thing
While having a whole house filter sounds great, you may not actually get to use one. If your home uses whole house air filters then you’re in luck - you can use them. If your home doesn’t have the system in place you’ll have to wait until you build a new home or upgrade your system. Before planning to upgrade your system you’ll need to consider the cost of the system and installation.
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