As a quick aside, both the air quality things I bought say not to rely on instantaneous readings but instead to use the aggregator average reading. One has the

As a quick aside, both the air quality things I bought say not to rely on instantaneous readings but instead to use the aggregator average reading. One has the ability to show averages and the other is more like "if the value is consistently higher than normal it's probably correctly 'high'" - so unless there's some weirdness in the Ikea one it shouldn't be switching colors unless you are very close to the threshold. It is possible that your air filter shakes or vibrates enough that it's kicking dust up, or you have poor indoor air quality. How often do you have to replace filters and how dirty are they? For reference I live in a forest, with pollen and dirt dust and people and pet dust, poor seals on windows, and open doors/screens, as well as high humidity year round; I buy the 3M 1000-1500 filters which are pretty beefy, and they last about two months before becoming uniformly dark grey on front and back. Ideally I'd replace them monthly but they're about $15 each and that adds up across three filters. I ask because I don't think my system does anything for VOC, I don't use carbon filters for the three, so I'm mostly filtering dust, pollen, clay, etc.