Four Tips to Consider when Choosing the Best Home Air Filter

Updated: 3/27/2025

Increasingly, homeowners want to have good air quality. Luckily, a good air filter can help ease their minds. It can help provide filtered, cleaner air by capturing a high percentage of potentially harmful airborne particles – such as smoke, dust, pet dander and allergens – as the air passes through the filter..   

But considering the local hardware store has many brands and sizes to choose, it's hard to know which one is the right for you – and not all air filters are created equal. Below are four steps to consider when buying a new air filter.

• Know your dimensions. This is the most basic consideration; check the owner's manual to identify which filters are compatible with your unit. If you don't have the manual, safely remove the air filter from your heating/cooling unit and record the filter's dimensions. For example, 20 x 25 inches or 20 x 16 inches are common length and height dimensions.
• Thicker is better. The other dimension to consider is depth. For example, a typical 1-inch fiberglass filter is usually replaced once per month. But a 4-inch filter with pleat designs offer a much larger surface area, so they can effectively trap more air particles and potentially last several months. For example, many replaceable Honeywell Home pleated 4-inch filters with 11+ MERV ratings can last 6 to 12 months, based on normal household conditions.

• 3. Consider the rating. Minimum Efficiency Reporting Value (MERV) ratings were set by the HVAC industry and used as a standard to define a filter’s ability to capture airborne particles from the air. Resideo offers filters with various MERV ratings: the higher the rating, the finer the filtration. The lower the MERV rating, the more frequently you’ll need to replace your filter. While the higher-rated filters cost more, the improvement in air quality may be worth it. Other companies use their own rating systems and generally the higher the rating number, the more the filter will capture as air passes through it.

• 4. The material matters. The material a filter is made of is an important decision, too. Media filters are at least 20 times more efficient than traditional fiberglass filters.

After you find the right filter, remove your old filter, put it in a large garbage bag to trap the dust and particles, dispose it and wash your hands. Then install your new filter. Most experts suggest you swap out your air filter at least once a month, but take into consideration the depth of the filter, whether you have pets, live in a dusty or polluted area or if someone in your family has severe allergies. Higher MERV rated filters can be replaced just twice each year.

How do you know when it's time to change the air filter?

• When you can see airborne particles and dust floating around in your home.
• If your utility bills are up more than normal. According to the U.S Department of Energy, replacing a clogged air filter with a new one can lower the air conditioner's energy consumption by 5 to 15%.
• If your HVAC system has been working overtime due to extreme hot or cold weather, your filter is trapping more airborne particles than usual. That extra workload can cause it to clog faster, so you may need to replace it sooner than expected.

Looking for more information about indoor air quality (IAQ)? Check out these myths and facts about IAQ and the coronavirus. As the seasons change, it's always a good time to call your local heating and cooling contractor to schedule a tune-up to make sure your air conditioner and/or furnace is operating correctly and is ready to carry the load when the temperature shifts  dramatically.