4 Inch Air Filters
Filterking manufactures 4" pleated air filters that are guaranteed to fit your AC or furnace perfectly. If you don’t find your size listed below, don’t worry! You can easily create a custom filter using our custom filter tool. Rest easy knowing that our products are backed by a 30-day guarantee, meaning you never have to stress about selecting the wrong size.
Available 4 Inch Air Filters
Can’t find your 4 inch air filter? Click here for Custom Air Filters
What MERV Rating Should I Use?
MERV stands for Minimum Efficiency Reporting Value. The rating tells you how effectively it captures different particle sizes. It's not the only rating system, but it is the only consumer standard available. No matter what type of HVAC filters you use, if the MERV rating matches, you'll get the same filtration quality.
Major home improvement retailers have developed their own rating systems that are similar to MERV, but not standard across brands and styles. The other filter rating systems are Microparticle Performance Rating, or MPR (created by 3M) and Filter Performance Rating, (developed by Home Depot) or FPR.
A MERV rating of 8 through 13 is recommended for households and many businesses. A good place to start would be a MERV 8 if no one in the home has breathing issues.
Air filters that fall within the 8 to 13 range can remove pollen, mold spores, lead or household dust, cooking dust, auto or welding fumes, and other similar contaminants. These air filters can catch anywhere from 20 to 85% of all particles, so they are ideal for home or office. These remove most particles while still remaining cost-effective.
But for homes with pets, allergies, and asthma patients, it is recommended you use MERV 11 as these can tackle pet dander and dust mites. For homes with smokers, it’s best to use higher-rated filters, MERV 13. Anything less and you won't adequately filter the smoke from the air.
We offer filters in a variety of MERV ratings. We also offer carbon filters to help combat odors. We do this so you can get what best suits your needs. You should only pay for what you need.
Why Should I Use a 4 Inch Air Filter?
The furnace filters you use in your home make a huge difference in the air you breathe. Even with good outdoor air quality, the air in your home is still full of allergens and other indoor pollutants - especially if you're a pet owner or a smoker.
These can have higher MERV ratings than something smaller, like a 2-inch air filter. A 4-inch filter will typically start at a MERV 8 and can range up to 16. Anything higher than a 14 is typically reserved for laboratories, hospitals, or other healthcare facilities that need the cleanest air possible.
However, you will definitely want to stay on top of replacing your 4 inch AC filter. If these get clogged up, it can put extra stress on your air conditioner. If you start to notice your energy bill increase or reduced airflow, it’s time for a replacement. Stagnant air is a sign that you need a replacement since dirty filters are less effective.
While you can technically use higher than MERV 13 in your home, it's generally not recommended. Air filters that are rated to handle more than household dust, pollen, mold spores, smoke, pet dander, and dust mites force your home's HVAC system to work harder than it needs to. Ultimately, this translates to more wear and tear on your heating and cooling system.
Keeping your air filters clean is a major part of maintenance, but using the wrong filter can be just as harmful.
Subscribe and Save for Better Air Quality
A 4 inch furnace filter lasts anywhere from six to eight months on average. We recommend changing your air filters regularly for the best air quality. This ensures the air in your home is free of airborne particles like mold spores, pollen, household dust, and dust mites.
Get air filters delivered to your door right on time. With our delivery subscription, you never have to worry about forgetting when it’s time for a replacement.
Plus, you will save on prices when you subscribe to our delivery service. Just select how frequently you want air filters delivered. Orders with two or more filters get free shipping, helping you save even more on your purchase.
Questions about air filter sizes?
4 inch air filters are thicker and last longer, so they are worth the investment if your furnace can handle them. They also allow more airflow, so your furnace doesn't have to work as hard to keep your home clean and comfortable. If you're not sure whether your furnace can handle a 4" filter, measure your current filter to see how deep it is. If it is 4 inches, then you can use a 4 inch air filter.
It depends on your furnace- if the filter slot is large enough, you can use it, but if it's less than 4 inches wide, you're stuck with using that thickness - typically a one to two inch filter.
Different size filters can be changed at different times. They fall into 3 buckets of sizes: 1 to 2 inch filters, 3 to 4 inch air filters, and 5 to 6 inch filters.
1 to 2 inch filters should be replaced every 1 to 3 months.
3 to 4 inch air filters should be replaced every 6 to 9 months.
5 to 6 inch filters should be replaced every 9 to 12 months.
If you have a pleated filter, replace it every 3 to 6 months.