HVAC ServiceYou may or may not have heard of MERV ratings in relation to your HVAC service. Do you have allergies? Is your family sensitive to common irritants or bacteria? Here’s the scoop: If one reason that you chose an HVAC system was to help filter your air, improve indoor quality, and trap airborne particles, then you need to know about the MERV rating.

What does MERV stand for?

MERV stands for Minimum Efficiency Reporting Value. It measures how well your HVAC system’s air filter traps airborne particles.

The standard was created by the American Society of Heating, Refrigeration and Air Conditioner Engineers (or, ASHRAE, an acronym you don’t need to remember). MERV ratings measure the effectiveness of an air filter using a 1 to 16 scale. Basically, the higher the MERV value, the more efficient your filter will be in trapping airborne particles like allergens like dust, fibers, mold, and even bacteria.

Is there a standard MERV rating professionals recommend?

No. In fact, many influential groups have different recommendations. The American Society of Heating, Refrigeration and Air Conditioner Engineers recommends a MERV rating of 6 or higher. In comparison, the U.S. Department of Energy recommends installing residential HVAC systems with a MERV rating of 13 and above.

What rating is typical, then?

It greatly depends on your HVAC service and the age of your appliances, but typically an HVAC system for home use has a filter MERV rated somewhere between 7 and 12. A more heavy-duty system, such as those used in a hospital or laboratory setting, would be more likely to have a MERV 13-16 rated filter.

Is higher always better?

Strangely, no. The higher the MERV rating for a filter, the smaller the pores are for air to flow through, which can create resistance and slow down whole-home efficiency in some systems. So while a surgical center may require a MERV 16, your home air conditioning system might be better off with a MERV 12 rating. Filters with higher MERV ratings also need to be changed more frequently than low MERV rated filters.

Why does my HVAC system’s air filter matter?

To ensure steady airflow, most experts recommend replacing your air filter every three months or so. Not only can a dirty filter block airflow, but contaminant build-up can waste 25 to 40% of the energy you are using to regulate your home’s temperature. Even worse, without an effective filter, allergens and other contaminants can pollute your home’s air.

While this may still seem a little confusing, rest assured that your HVAC repair or installation professional will know what you need. Your local HVAC service can help you determine which MERV rated filter will still allow for maximum airflow in your system to get you the cleanest air quality.

With the right air filter, you’ll be able to breathe easier both literally and figuratively.