My background is in running large scale data centers. I've had a lot of experience with airflow management for cooling very hot computers. Airflow is critical.

My background is in running large scale data centers. I've had a lot of experience with airflow management for cooling very hot computers. Airflow is critical. Moving air around is critical. If you have 'zones', then you'll need more filters for sure. It sounds like you're in a warm environment. I used to live in Vietnam where the air is generally terrible. Do you have one of those AC units in the house on the walls? When was the last time you had them cleaned? I ask because those AC units are horrid... they collect huge amounts of dust and mold and nobody thinks to clean them properly (it isn't easy)... they are basically spraying out nasty shit. If you can, turn them off and get used to the heat. I did that and stopped getting sick all the time. People say running AC makes you sick... it isn't the cold air, it is these nasty units. If it is central AC for your HOA, I'm sure they've never been cleaned... or at least not often enough... Mila is definitely a bit of a marketing gimmick, that said, the product is quite nice (noise, design and visual) and another good thing is that their support is excellent. I'm actually on my 3rd unit now because of production defects they've had (and since resolved). Being able to just email them and have them ship me a new unit in a couple days is a really nice aspect of paying a bit of extra money for these things. I've also built the 3 filters to a box fan [0]. That works extremely well too, but is a lot louder and takes up a lot more space than the Mila, and doesn't look as nice. (The link I give you is kind of the extreme version, you can go a lot simpler than that.) I bought the Mila highest end filter. It is excellent. Heavy (clearly full of dense carbon). Well made. The optional, also over priced, sock really helps keep it clean (you could probably make your own with similar fabric). I'm sure the filter will last a couple years in my current relatively clean environment. I also vacuum the filter when I clean the sock, to help it last longer since these things are kind of expensive. [0] https://www.youtube.com/watch?v=lbWiZSsEqPg https://www.youtube.com/watch?v=lbWiZSsEqPg