There are a wide variety of air filters available, and choosing the right type for your home may seem like a daunting task. It’s important for you to check your heating and cooling systems’ owner’s manuals to see what type of filter has been recommended by the manufacturer. The manual will also provide a recommendation as to how often you should change or clean the filter.
Here are some terms you may come across when researching air filters:
- MERV. This acronym stands for “minimum efficiency reporting value.” The term describes the porousness of a filter from 1-16. Most air filters have a 4-13 MERV.
- ASHRAE. This acronym is for the American Society of Heating, Refrigerating and Air Conditioning Engineers. You may come across air filters that are ASHRAE-rated or approved.
- 1-4 MERV. These filters are not very expensive and will trap 80% of particles 50 microns or larger. They will trap 25% of particles 3-10 microns in size.
- 5-8 MERV. These filters are slightly more expensive and will trap 80-95% of particles 5 microns or larger.
- 9-10 MERV. These filters can be disposable or washable. They are made of self-charging fibers that help to trap particles from the air. Disposable versions are pleated while washable ones are not.
- 11-13 MERV. These filters can trap particles that are 0.3 microns or larger. They are fairly-thick (2-5 inches).
- High-efficiency filters. These are better known as HEPA filters. They can also trap particles that are 0.3 microns or larger, but they must only be used in compatible systems.
While it may seem like a good idea to use the highest MERV-rated filter possible, it may not be what is best for your heating and cooling system. MERV 11 or higher air filters can greatly restrict air flow. This can increase your systems’ runtime, costing you more money each month on your utility bills.
These are only recommendations. So, what if you live in a home that is very dusty, or in a home with individuals who suffer from allergies? You may need an air filter with a different MERV, or you may need to replace your filter more often than usual.