4-inch vs 1-inch Furnace Filters: What is different and Which One is better?

Home Tips

Furnace filters protect the mechanism of furnaces as they prevent them from getting dirty while removing particles from the air we breathe. The manufacturing materials of climate filters include but are not limited to fiberglass, cotton, and polyester. If you wonder about the difference between a 4-inches and a 1-inches furnace filter, as you might want to purchase one that will fit your requirements, read on to learn more about it.

4-inch vs 1-inch Furnace Filters

4-Inch vs 1-Inch Furnace Filters

Let us get straight to the point; the 4-inch furnace filter will provide you better air quality indoors. However, in the end, it all comes down to your requirements, budget, furnace system, and maintenance preferences. If you opt for the 4-inch furnace filter, you will be spending some extra cash compared to your 1-inch furnace. If you suffer from allergies or asthma, you definitely won’t want to compromise on air quality. The 1-inch furnace filter typically requires to be changed once a month. On the other hand, the 4-inch furnace filter is more likely to last you for up to 6 months.

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4-inch vs 1-inch Furnace Filters
Image by Bob Vila

Suppose your furnace system calls for a 1-inch furnace filter. Still, you want to have the benefits of the 4-inch filter. However, you should know that by forcing a 4-inch filter into a system made for a 1-inch furnace filter, the filter’s efficiency will get damaged and also impact the furnace system. If you still cannot decide about the perfect furnace filter for your system, you will have to compare both types of furnace filters based on cost, air quality, and maintenance.  

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The MERV rating of a filter sets its cost. On average, a 4-inch filter’s price is $55, whereas the cost of a 1-inch filter is $20. In other words, a high MERV will cost you more than a low MERV. Undoubtedly, the 1-inch furnace filter will cost you less initially. However, you will have the filter changed at least once a month. With that said, you could be saving more money with a 4-inch furnace filter as you won’t have to change it as often. Suppose you spend $40 on the 4-inch furnace filter. You will have it changed twice a year, which is good for your pocket.


Change furrnace filter
Image by Arthaey Angosii

As we stated earlier, the 4-inch furnace filter will be required to be changed less often than the 1-inch furnace filter. The 4-inch filter’s pleats are large, which indicates their greater surface area to catch and filter polluting particles. A 4-inch furnace filter’s pleats are up to five times longer than the pleats of a 1-inch filter. If we talk about maintaining a 4-inch furnace filter, it can even last up to a year. Most climate experts recommend changing the 1-inch filter once a month. That said, the maintenance of the furnace filters also depends on the air quality of your home. For instance, if you have pets or live in an area with a lot of surrounding traffic, you will be changing your furnace filter more often.

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Air Quality

If you aim to improve your home’s air quality, your focus should be on the filter’s MERV (Minimum Efficiency Reporting Value) and not so much on the depth of the filters.  If you want a filter with a high MERV, we recommend going for the 4-inch furnace filter – or other filter dimensions that you see fit for your home.

However, ensure to prevent it from getting clogged. With that said, the 4-inch MERV filter will definitely improve the quality of the air inside your home.  

MK Akram
I began writing as a professional on my personal blog and then discovered my true calling, which is writing about technology, News and gadgets in general. I have been a technical writer, author and blogger since 2010. An industry watcher that stays on top of the latest features, extremely passionate about juicy tech news and everything related to gadgets. Learn more about furnaces at Climate Experts.