I had a nice UV air filter and we were healthy. Then the stupid ballast burned out and we became sick as dogs this year. Isn't that a great correlation? Don't you just absolutely believe it?
But I am serious about UV C on titanium oxide. That makes a house smell like fresh sunshine on white sheets. Lots of papers on how it removes viruses and fungal stuff. I think it has good physics.
But these home air filters are made like a Tesla3, no quality, and they are unfixable. I made a couple of attempts to get the bulb going again, but failed. Then I found a 13W UV sterilizer compact fluorescent bulb on Ammie. I'm not going to give any more hints than that, because these things are dangerous.
They can burn your eyes out, but they take about 5 minutes to warm up, so you can be careful. I put this inside the air filter and it works great. All these air filters have expensive super-thick filters that are useless. I substitute with a single layer of electrostatic filter cloth, sold as a hammock filter.
Now I'm doing another filter. Take out the ridiculous huge filter. Buy some 'titania white' acrylic paint from ammie and coat the inside. Titanium oxide is the best UV filter and will protect the paint. I just use a pig light bulb socket and put in a new cord. That way I don't have to blow the air filter to pieces like I did with the other one.
This will give you beautiful air. You can just breath it in all day. There may be a bit of ozone produced, but that's produced, as well, on a sunny day. I wouldn't go all nuts about it like some people do. You can tell if there's ozone, it crinkles the nose. Heavy ozone is deadly, but a touch is quickly consumed by dirt. It a balance between ozone or fungus. blah.
ps. Explanation for Tesla3 joke. If the quality inspectors are there to put in loose screws, you have a problem.
pps. No, I am not giving a detailed explanation, this for Super-Master-Fixers.
add: Funny, I've received two new bulbs and each one burned out right away. The original bulb is still working fine.