I live in a 1400 foot cottage and use the fireplace everyday when the temperature is below 50 degrees, which is a lot here in NW Michigan.
This makes for low heating bill but not very good quality air. The Alen purifier outperformed the prior purifier I was using which just couldn't keep up. I like the color button which shows what level of unhealthy particles are being handled as its running. It is satisfying to see it go from purple to green; however it pretty much runs red most of the time because of the constant fire. It does take it down to green in the evening when the fire gets low. Where it really shines is keeping the smokey smell out of the house, including off my clothes, walls and upholstery; this indicates, to me, that it is constantly putting fresh air out while intaking the bad stuff.