They'll let some dust particles through and fill the air when the stove or air conditioner is on, but hey, they're not described as effective for everything, no matter the size . They do their job very well, but if you want dust-free, ultra-clean air, you need a more stringent (and more expensive) filter. In the winter they last about a month (it says "up to 90 days"), but that's to be expected since I have an inefficient stove that works a lot and a large house with very high ceilings. One filter a month is of course acceptable. In spring and autumn they may last 2-3 months. Summer is again about a month because the air conditioner works a lot.
NANPU Air Drying System With Double Filters And Pressure Regulator Combo For Clean And Controlled Air Supply
18 Review
NANPU 1 FRL Air Filter Regulator Lubricator Combo With 0-150 Psi Gauge, 5 Micron Brass Element, Poly Bowl & Semi-Auto Drain - Metal Bracket Included
20 Review
NANPU Compressed Air Filter Regulator Combo: Brass Element, Semi-Auto Drain, 0-150 Psi Gauge, And More
21 Review
NANPU 1/2" NPT Air Drying System - 5 Micron Particulate Filter, 0.01 Micron Coalescing Filter, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl W/Metal Gauge
23 Review