How often should I change my furnace filter?

The general recommendation is to change your furnace filters at least every 90 days. However, this is just a generalized recommendation, and other factors come into play that can decrease the longevity of the furnace filter. If you smoke, vape or have indoor pets, it might be better to replace your air filters every 60 days. If allergies or asthma are an issue in your household, replacing your filters every month could help keep the air cleaner, especially with a higher MERV rated filter.

How to change my furnace filter?

Your furnace filter is located in a vent either on an interior wall or in the ceiling. The vent is usually white, but can sometimes be painted the same color of the wall. Simply pull the little level on the side to open the vent. Remove the old filter and replace the new furnace filter.

When should I change my furnace filter?

When you change your air filters depends on the indoor air quality levels you want to achieve. While Filter King filters can last 90 days, you may want to change them sooner. There are several factors that go into when you might want to switch out the current furnace filter. If you have allergies or asthma, a fresh filter can help with indoor air quality. If you have pets or smoke, then changing air filters sooner than 90 days can keep the air quality fresher.

Where is the air filter located?

Depending on your AC unit, the air filter slot may be located in a hard to find location. First, try checking the blower compartment or return air duct where the air is cleaned before going through the unit. The unit itself may have the air filter inserted in a specific location.

Can I run my Furnace without a Furnace Filter?

Yes, but it is not recommended that you do so. There are several issues that occur for an AC unit, your home air system, and the home itself when an air filter is not installed. Think of an air filter as a gatekeeper (which really is), and its purpose is to protect both you and your AC system from dust and dirt, that if left unfiltered, can cause harm to both you and your AC unit in the long run.

What happens if the air filter is backwards?

Air filters are built with a tight mesh weave that is designed to capture and absorb incoming particles. Air is brought through the porous side, and the mesh weaving allows it to flow in and out while being cleaned. When backwards, air has a harder time coming through, which means the system will require more energy to push it through, and thus affecting the quality of air filtration. When an air system is strained like this, it causes a rise in home energy billing and possible mechanical damage.

Will a dirty air filter affect my AC?

Yes, over time dirty air filters will affect AC more and more. The longer an air filter is left in a system, the dirtier it becomes, and the more pronounced the effects will be. There are many factors that determine how long an air filter can last such as the type of filter, material, home size and daily habits. The higher the FPR rating system (developed by Home Depot), the longer the filter lasts. MERV rating is another popular rating system used both locally and internationally.

What happens if the furnace filter is dirty?

When your air filter is dirty, the mesh wearing that it consists of becomes clogged and full of dirt and debris. When this happens, the air that is supposed to flow forward through the filter has a harder time passing into the air system. The system will use more energy to try and push the air forward, straining itself and raising your energy billing in the process. The air inside your home may also start becoming stagnant and dirt over time since fresh air is unable to come in.

Are furnace filters important?

Yes, they are very important to any air system they are in. Air systems have no way of knowing whether the air they are bringing in is clean or dirty. Air filters are essential to making sure that any air brought in is cleaned before entering the system. Without filtration, the air coming in from outside may contain any number of dust, debris pollutants, and allergens.

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We make finding the right HVAC filter simple. Browse our standard air conditioner filters by selecting your dimensions, or get a precision-cut custom size to match your exact specifications. Order a Custom Air Filter.

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MERV ratings measure how much your filter captures – from everyday dust to fine allergens and pet dander. Find the right level for your home below.

Standard

Dependable everyday filtration that covers dust, pollen, and pet dander in standard homes without allergies or sensitivities.

Advanced

Advanced filration for homes with pets, kids, or mild allergies - captures fine dust and smoke particles that MERV 8 misses.

Ultimate

Superior protection for households with allergies, asthma, or immune sensitivities - filters bacteria and virus carriers down to 0.3 microns.

Carbon

Solid everyday filtration combined with activated carbon that absorbs smoke, cooking odors, and pet smells that standard filters can't capture. (edited)

GUIDE

How often to change an air filter

For most homes with a 1-inch filter, 60–90 days is a reliable baseline. But filter type, thickness, pets, allergies, and local climate can all shift that window – sometimes significantly. Read this guide to find the right schedule for your home.

Read the Guide

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We stock thousands of standard and non-standard sizes, and make custom filters to order – so you'll always find the exact fit for your system.

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