Fish got to swim, and birds got to fly, but furnaces need to breathe to operate correctly.  Your furnace filter operates all year long through both the heating and cooling season and is most often located where the air returning to the furnace enters at the bottom of the unit. These filters remove small debris and particulates from the air stream and come in a variety of efficiencies and sizes.  If these filters get too full, they restrict air passing through the furnace and over the air conditioning coil reducing heating and cooling efficiencies, and potentially cause equipment failure.



The purpose of your HVAC system is to keep you comfortable while at home.   It depends on how much debris you have in your home’s interior air.  Those with pets may need to change their filters more often.  Some thin (1”) filters are recommended to be changed monthly.  Some of the thicker (5”) filters can last 6 months to a year.  Know your filter manufacturer’s recommended replacement parameters or ask your HVAC service provider for details.  Changing your filter regularly is by far the most important step you can personally take toward assuring the continued trouble-free operation of your comfort system.


High-efficiency air filters 

High-efficiency air filters are a cost-effective way to help improve indoor air quality, which may be beneficial to family members sensitive to allergens and other particles in the air.  Air filters also help keep your furnace’s coils and heat exchangers clean, which may prolong furnace life and keep it running efficiently.



The Air Filter Performance Rating System (FPR) ranks all brands of filters by measuring their ability to capture large and small particles.  It also factors in the weight gain caused by the filtration process over the filter’s lifetime.  The FPR creates a weighted average for each filter, which is then ranked on a 1 to 12 scale, with 1 being the lowest performance and 12 being the highest performance air filter.  The best air filters for home use are those with the best FPR ratings.  Sixty percent of the rating is determined by the filter’s ability to capture large particles, 30 percent is determined by its ability to capture small particles and weight gain over the filter’s lifetime determines the final 10 percent.



The MERV rating system helps you choose the best furnace air filters to fit your home’s needs.

Each rating dictates the effectiveness of a filter.  The higher the MERV rating, the more efficient the filter.  The American Society of Heating, Refrigeration and Air Conditioner Engineers (ASHARE) recommends a MERV 6 or higher.  Most people go with a MERV 8 filter.  Most residential areas can remove contaminants with MERV 8 to MERV 13, while most hospitals use MERV 14 to MERV 20.

While FPR’s rating system goes from 1 to 12, MERV’s rating system goes from 1 to 20.  FPR 10 is similar in strength to MERV 20, since they are both the highest rating value.  However, FPR 1 doesn’t necessarily equate to MERV 1.  It isn’t until FPR 4 and 5 that filters start trapping larger particles like household dust and lint, dust mites, pollen and pet dander.  Meanwhile, MERV 1 to 4 will trap all these pollutants.  Some examples of MERV below:

  • MERV 1 to MERV 4: Pollen, dust mites, standing dust, spray paint dust and carpet fibers.
  • MERV 5 to MERV 8: Mold spores, hair spray, dust mites, animal dander and cement dust.
  • MERV 9 to MERV 12: Humidifier dust, lead dust, auto emissions and milled flour.
  • MERV 13 to MERV 16: Household dust and pollen, pet dander, outdoor pollution, mold spores, microscopic allergens, bacteria, most tobacco smoke, sneeze bacteria and virus carriers.


Contact us

If you have furnace maintenance for your office or home, join hands with a licensed and insured contractor at East Coast Mechanical.   Email: ecmcecmc@aol.com  Address: 5133 W Hurley Pond Rd Suite A, Wall Township, NJ 07727 Hours: Monday to Friday 8 AM to 5 PM and Closed Saturday and Sunday.

Phone:  800-300-ECMC or 732-751-8877


Furnace Maintenance