What Are the Benefits of MERV Furnace Filters?

The Minimum Efficiency Reporting Value (MERV) is a number that gives the efficiency of an air filter at its lowest performing level. Using the MERV number system, you can compare furnace filters to determine the most efficient option for your particular use. The best furnace filter will be affordable but will eliminate enough airborne particles to create a clean air environment in your residence or workplace.

Because each filter’s rating represents its lowest possible performance, the MERV number on a furnace filter tells you how much it will trap in a worst-case scenario. But there is always potential for it to do better because it is a minimum, not a maximum. It can be beneficial to look at what the ratings mean and what would be best for your residence, especially if you have pets, allergies, or chronic illnesses, so you can breathe cleaner air with a MERV air filter.

How the MERV Rating System Works

The MERV Rating System works by comparing a filter’s efficiency to the particle size that it is able to capture. This means that filters with lower MERV ratings will only trap larger particles, and fewer of them, while filters with higher MERV ratings will trap more particles of smaller sizes.

Although MERV ratings can go down to 1, furnace filters with MERV ratings between 6 and 8 are considered the bare minimum. These filters will protect your HVAC system but are not the most effective at capturing airborne particles. Filters with a MERV rating of 8-10 are considered the most affordable middle-ground option for residential homes, while filters with a MERV rating of 11-13 are more effective, especially for homes with pets or people with Asthma, but also more expensive.

Filters with MERV ratings above 13 are not recommended for residential use. Although these air filters are very efficient at trapping air particles, they can severely restrict airflow in a building and are large and bulky. A residential HVAC system is generally not equipped to handle such air filters, and they are reserved for places such as medical facilities requiring more air filtration.

The Benefits of Each MERV Rating

Each MERV rating is suitable for different things, so it is beneficial to consider what you are trying to protect your air against as you figure out which rating to buy.

MERV 1-4:
These are one of the cheapest options for a MERV air filter. They protect against larger particles such as pollen, dust mites, standing dust, and carpet fibres. They are often used in window air conditioning units.

MERV 5-8:
These are the absolute cheapest option for a MERV air filter and are considered the bare minimum for residences. They are able to capture slightly smaller particles such as mould spores, hair spray, and cement dust. At MERV 8 it will have 90% efficiency on particles of 3 to 10 micrometres in size. You can probably get a MERV furnace filter in this range if you do not have pets or allergies.

MERV 9-13:
These are a bit more expensive than air filters with a lower rating but offer better protection. They can capture particles in the 1 to 3-micrometre range and trap nearly all larger particles. They provide effective air filtration for a cleaner environment and easier breathing if you have pets or allergies. MERV 13 is considered the highest rating for residential use and the best overall.

MERV 14-16:
These are the most expensive option and not recommended for residential use, but they are able to trap particles down to 0.3 micrometres in size. They can trap airborne bacteria, most tobacco smoke, and pollutants released through sneezing. As a result, these filters are often used in places like medical facilities and smoking lounges where air sanitation is of utmost importance.

Selecting an air filter with a MERV rating gives you insight into the size, amount, and type of air particles that will be eliminated from the air. For most residences, a MERV rating of around 8 is adequate for a clean air environment, while a higher rating may be necessary if you have pets, allergies, or chronic illnesses. By changing your air filter regularly and using one with a MERV rating, you can rest assured that your air quality will be clean and free from pollutants.