You may not give a lot of thought to your home’s air filter. An air filter, with no moving parts, is a little part of a big system, and it doesn’t typically “break down.” But this doesn’t mean that air filters aren’t important — they protect your expensive HVAC equipment and can improve the quality of your indoor air. Manufacturers generally recommend you change air filters every 2 to 3 months and while you’re at it, you should be considering the type of filter you’re using.
MERV stands for Minimum Efficiency Reporting Value and it indicates the efficiency with which air filters trap particulates. The higher the rating, the better the filter is at capturing small particles like bacteria, viruses, pollen, and mold spores. The MERV rating scale is 1 to 20, with most standard filters in the 1 to 16 range.
Types of filters:
Too much of a good thing?
It might seem like the higher the MERV rating, the better — but that’s not necessarily the case. For one thing, you need to balance out the expense with the need; you may not need such a high performing filter. And for another, there is such a thing as too much MERV!
The higher the MERV rating, the smaller the allowance for air flow. An ultra-high efficiency filter can actually reduce efficiency and even cause damage to residential HVAC systems by slowing airflow across the heat exchanger which can cause overheating.
Before you consider installing a HEPA filter, it’s worth doing some research to determine the optimum MERV rated filter that allows for maximum airflow. It might be worthwhile to have a certified HVAC professional help you determine which filter is best for accommodating both your equipment and your indoor air quality needs.