These are loud, about as loud as a good stove hood. They are quieter than the hydroponic scrubbers recommended above. This isn't really the kind of device you h

These are loud, about as loud as a good stove hood. They are quieter than the hydroponic scrubbers recommended above. This isn't really the kind of device you have on all the time. I use it with an AQI monitor during high-particulate events like cooking, smog, wildfires, etc., to clean my apartment's air. The AQI outside where I live has routinely been around 100-150 PM 2.5, while a few runs for 5-15 minutes every time I leave or enter keeps it around 5-15. It is hard but possible to have a conversation when it is on full speed. Mine has a knob you can adjust the fan speed, which obviously trades off with CFM, but makes it easier to have a conversation. But they work really fast at max speed. I cook a lot in a hot oil wok on a gas stove. My "hood" is a fan built into my microwave above the oven that just recirculates air in the room, and I have just one small window in my kitchen. If I forget to turn my scrubber on while cooking, it only takes about 10-15 minutes for my PM2.5 sensor at the other end of my kitchen to go from 500+ to about 10.