Minimum Efficiency Reporting Value is the scale that is used to test the ability to stop particles as the air passes through the filter of your home comfort system.

MERV was developed by the American Society of Heating, Refrigeration, and Air Conditioner Engineers – ASHRAE.

MERV values vary from 1 to 16 – the higher the rating, the more efficient the filter will be in trapping airborne particles. It’s important to consider airflow needed for your HVAC system when picking a filter and also for maintaining your filter. If the filter restricts the airflow too much, multiple problems can occur, and the efficiencies or life span of the system could be affected.

ASHRAE recommends MERV 6 or higher, the US Department of Energy recommends MERV 13, and LEED (Leadership in Energy and Environmental Design) recommends MERV 8 at a minimum.

Because we often find home comfort equipment issues related to filter problems, you should invest in the following systems:

The Carrier EZ Flex system (pictured to the right), provides whole-home air filtration using a high-efficiency filter. The deep-pleated style of its MERV 10 filter keeps air flowing while removing up to 65% of airborne particles as small as 1.0 micron.

CPS also highly recommends the Infinity Air Purifier (pictured to the left) that works silently in-line with your HVAC system and can make the air you breathe healthier. It uses Captures & KillsTM technology to trap up to 95% of particles then uses an electrical charge to kill or inactive them. With MERV 15 technology, it will trap up to 95% of particles then uses an electrical charge to kill or inactive them.

We often find problems when customers use the 1” thick pleated filters (MERV 7-8 pictured below) because the airflow can be restricted by the filter as soon as it’s installed or shortly after when the filter traps dirt. If you are not ready to invest in one of the above–mentioned systems, CPS suggests going with a lower than normally recommended MERV filter. The one inch thick EZ Flow standard MERV 4 (pictured below) style can be used for most applications instead of using a filter that would restrict the airflow of your home comfort system. The filters first job is to protect the heating or air conditioning equipment, and if the proper filtration unit is installed correctly, you can also enjoy the benefits of cleaner air throughout your home.

Here are a few things to take with you from this article:

• Always have a filter on your home comfort system.
• Choose the proper filter with proper airflow in mind.
• Check & change the filter regularly. The Carrier EZ Flex and Infinity system filters do not need to be changed as often due to their high capacity design.
• If you have allergies or other health problems, invest in a good filtration unit and have it installed on your furnace and air conditioning system.

The chart below shows the values of efficiency for each MERV rating.