Do ductless mini-split heat pumps filter fine particles out of indoor air?
Ductless heat pumps, or mini/multi split heat pumps, are an alternative to radiator or baseboard heating, as well as replacement for window units for cooling. A head unit, or multiple head units, are mounted on the interior wall or ceiling, with an accompanying unit outside. The outside unit extracts heat from the air, even when it’s cold. Refrigerant carries the heat directly to the head(s) inside, which then delivers heated air to occupied space. In warmer months, the system works in reverse for quiet, efficient air conditioning.
Ductless mini-split heat pumps generally do not filter fine particles in the air passing through the device. The filters typically installed in mini-split heat pumps are designed to protect the equipment from clogging with large particles like pet hair and lint, and do not filter out fine particles.
Some ductless mini-split products claim to have higher-efficiency filters that can remove fine particles from the indoor air. To verify these claims, check that the filter has a MERV 13 or higher rating. If the filter does not have this rating, it may not be consistent with EPA’s recommendation for using a high-efficiency filter. Make sure the filter fits snugly so air does not leak around the filter, and you do not have to bend or crush the filter to make it fit. It is also important to note that ductless mini splits will primarily filter the air in the room where they are installed and only when the system is running. If you have questions about the filtration capabilities of a specific mini-split unit, consult the manufacturer or an HVAC professional.
If your ductless mini-split heat pump does not have a high-efficiency (MERV 13 or higher) filter, or if you are unsure, consider using a portable air cleaner to filter particles from the indoor air. Learn more about selecting air cleaners and filters in EPA’s Guide to Air Cleaners in the Home.
For more information on ductless mini-split heat pump systems visit:
• EPA’s Heat Pumps
• Energy Star’s Ductless Heating & Cooling
• Department of Energy’s Ductless Mini Split Heat Pumps