Can I Use a 4 Inch Filter Instead of 5?

If you're looking to improve air quality in your home, you may be wondering if you can use a 4-inch filter instead of a 5-inch filter. The answer is yes, reducing the thickness by one inch shouldn't be a big deal. However, it's important to focus on the MERV rating of the filter, as this will determine how effective it is at filtering out contaminants and allergens. When it comes to air filters, the thickness is what determines the surface area.

A 4-inch filter will last longer and provide better air quality than a 1-inch filter, as it has a higher MERV rating. This means that it can filter out supermicro contaminants such as bacteria, viruses and dust particles. Most HVAC systems can be adapted to fit these thicker, high-efficiency filters. It's important to make sure that the filter rating allows for proper airflow and filter level, as increasing the filter density may affect the efficiency of the unit.

Ideally, only a small amount matters as long as the existing filter is sealed against the outflow as indicated by the arrow. These media filters have much stiffer cardboard frames, and some media filters even have plastic “rails” on the top and bottom so you can slide them inside the oven with a very tight seal. This means that you don't have to change them as often as smaller filters require (i.e. 1 to 3 months).

So not only will you clean the air better, but you will get much more airflow than the standard one inch. If improving air quality is a priority for you, filter depth doesn't matter as much as MERV. As mentioned above, small filters with high MERV ratings can quickly prevent airflow when they get dirty. The clean and clear end result is that size does matter when it comes to air filters - but it's the thickness that counts. Thicker filters, known as media filters, are generally 4 to 5 inches thick compared to ubiquitous 1 inch filters that you can even buy at grocery stores.

For example, because you will change 1-inch high MERV filters more often than 4-inch filters (see maintenance section above), you could save money with a 4-inch filter depending on the MERV you get.