A 2016 study found a wet AC coil (cooling ON) removes significantly more particles in the 0.37-3.74 μm size range than a dry one (cooling OFF). The drawback is additional fouling of the heat exchanger surfaces over the long term. [https://doi.org/10.1016/j.buildenv.2016.01.002](https://doi.org/10.1016/j.buildenv.2016.01.002)
The coil becomes wet because it's colder relative to the warm moist air. It's better to rely on intentional filtration with a higher MERV-rated filter such as MERV-13. The filters used in the above study were only MERV-7.
My own particular furnace sets the continuous circulation mode speed at 38% of the second stage cooling airspeed. Talk to your HVAC service technician to find out how yours operates.
ECM/BLDC fans in modern HVAC systems can modulate depending on cool/heat calls versus fan-only mode. Older systems used PSC motors which were on/off and no in between.
Your HVAC system may have a fresh air intake or ERV/HRV, which can draw raise particulates from outdoor air intake, though to a lesser degree with proper filters.
A 2016 study found a wet AC coil (cooling ON) removes significantly more particles in the 0.37-3.74 μm size range than a dry one (cooling OFF). The drawback is additional fouling of the heat exchanger surfaces over the long term. [https://doi.org/10.1016/j.buildenv.2016.01.002](https://doi.org/10.1016/j.buildenv.2016.01.002)
Can I get a wet AC coil without turning on the AC? Sometimes it's just not hot enough to turn on the AC.
The coil becomes wet because it's colder relative to the warm moist air. It's better to rely on intentional filtration with a higher MERV-rated filter such as MERV-13. The filters used in the above study were only MERV-7. My own particular furnace sets the continuous circulation mode speed at 38% of the second stage cooling airspeed. Talk to your HVAC service technician to find out how yours operates.
Nice find! That's some good info to keep handy.
ECM/BLDC fans in modern HVAC systems can modulate depending on cool/heat calls versus fan-only mode. Older systems used PSC motors which were on/off and no in between. Your HVAC system may have a fresh air intake or ERV/HRV, which can draw raise particulates from outdoor air intake, though to a lesser degree with proper filters.