What Are MERV Ratings, and Why Are They Important?

A MERV or Minimum Efficiency Reporting Value lets people know how efficiently an air filter can work to remove pollutants from your home. The American Society of Heating, Refrigerating, and Air Conditioning Engineers or ASHRAE designed MERV to make buying air filters easier. Here’s some more information about how MERV ratings work and how they can impact your St. Cloud, Florida, home’s indoor air quality, your energy use, and the condition of your HVAC system.

How MERV Ratings Work

Filters with higher MERV ratings can remove smaller particles from your home’s indoor air. The MERV scale goes from 1 to 20. An air filter with a MERV rating between 1 and 3 captures less than 20% of large particles with diameters of 3 to 10 microns. These substances include dust, pollen, moss, paint, clothing fibers, pet hair, and human hair. An air filter with this rating is usually washable, so you won’t have to worry about paying for replacements every few months.

Filters with a MERV rating of 4 are usually made of fiberglass and can catch dust mites along with larger particles. They’re very inexpensive, but you’ll need to change them every month to keep your HVAC system working well. A pleated cotton filter with a rating between 5 and 7 can catch up to 70% of large particles. Air filters with ratings from 8 to 10 will capture around 85% of large particles and half of the small particles. These include some types of bacteria, biological growth, and smoke.

Whole-home air purifiers or air cleaners usually have a MERV rating between 9 and 16. A professional will install this type of filter in your HVAC system’s ductwork to supplement your existing air filter. It can catch most small particles and even some viruses. Hospitals and rooms used for assembling or repairing sophisticated electronics sometimes use filters with even higher ratings that can remove even the tiniest particulates from the air. However, they’re much more expensive than other options.

Your Indoor Air Quality

Filters with higher MERV ratings will improve your home’s indoor air quality. The right air filter can prevent asthma or allergy symptoms, eye irritation, sore throats, rashes, headaches, fatigue, and many other health problems. It can also reduce dust in your home and keep biological growth from damaging your walls, ceilings, floors, or furniture. Filters with high ratings can even keep the flu, colds, and other illnesses from spreading through your home. A high MERV rating is especially useful for people with allergies or weak immune systems from injuries or diseases.

Your Energy Use

Since air filters with higher MERV ratings send the air in your house through smaller openings, they require more energy to work well. Choosing a filter with a rating that’s too high could raise your utility bills. Most air filters have MERVs between 8 and 13. They work well for people who don’t have allergies or other health problems, and they shouldn’t increase your energy bills as long as you change them regularly. However, getting rid of unpleasant symptoms is worth using extra power for many people.

The Condition of Your HVAC System

Filters with low ratings can let dust and other pollutants spread through your home’s ductwork, increasing maintenance costs. If you choose a filter with a rating that’s higher than the one recommended for your HVAC system, it will decrease your airflow and make you and your family too warm or cold. It can also increase wear, shorten your system’s life, and lead to uncomfortable breakdowns. Before you choose an air filter for your heater and air conditioner, ask a professional which MERV rating will keep it working well and maximize your comfort.

Frank’s Air Conditioning has more than 25 years of HVAC and indoor air quality experience. We received the Angie’s List Super Service Award in 2017, and we’re a Trane Comfort Specialist. We can recommend the best air filter to keep your St. Cloud, Florida, home comfortable, conserve energy, and make sure that your heater or air conditioner keeps working well. For quality service from our friendly experts, call us at (407) 490-2070.

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