The filter works great! After a February install, within two days of use, my asthma was greatly relieved (less dust/mold spores) and hubby, with COPD, was noticeably using his inhalers less often. Later, while the California wildfires were raging, we ran just the A/C fan and kept the house, inside, an ashless oasis. (Outside, the solar panels output had diminished by half from the ash fallout, before they were cleaned.)I couldnt believe how quickly the difference was felt with the inside air quality, after this filter was installed - and what a lung-saver during the worst of the fires!
They work, but the dimensions listed are, shall we say, exaggerated. The filter says 16x20x4, but the thing sits in the slot loose and has a gap above it, letting air bypass. I will use the ones i purchased, then try to find a brand with more accurate dimensions.