Do heating and air-conditioning filters affect energy use or indoor air quality?

A wide range of filters for central heating and air-conditioning systems exists on the market, and advertisements tout the ability of high efficiency filters to protect occupants from dust, dirt, pollen, dander, mold spores, and other airborne particles. At the same time, governmental organizations caution that high efficiency filters can become loaded with dust and increase energy consumption. This work attempts to experimentally clarify these claims by assessing both the energy and indoor air quality implications of heating and air-conditioning filters in residential and light-commercial buildings, using a range of commercially-available filters in both occupied homes and businesses and an unoccupied test house.

Although higher efficiency filters are widely assumed to increase energy consumption, our research has found evidence contrary to this claim. While higher efficiency filters typically decrease the airflow rate through heating and air-conditioning units by 5-10%, we have seen no significant differences in energy consumption due to higher efficiency filters. Additionally, we have developed novel test methods to measure the field performance of filters for removing particulate matter, and our results show that higher efficiency filters can achieve significantly greater particle removal than lower efficiency filters. Thus, our work has shown that indoor particulate matter concentrations can be decreased by higher efficiency filters at minimal to no additional energy costs in residential and small commercial environments, although the cycling operation of heating and air-conditioning systems can diminish the effect that filters can have on indoor air quality.