
Coway
Airmega AP-1512HH Mighty
Durable, effective, but struggles with strong odors.

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I've had a Honeywell HPA060 in the room with the liter box since 2013. It's still going! I also have the larger version HPA 160 in each bedroom to help with allergies. When the wildfire smoke summer came to the region, our indoor air quality was still fine while it turned yellow outside. It basically only has 3 fan speeds, a true HEPA filter and a carbon filter. Option to buy carbon prefilter with added zeolite for more odor absorption. I should mention that as a former pet sitter, getting an air purifier to handle litter box odor rarely works. The amount of odor causing material that renews the smell basically overpowers any air purifier's capacity to absorb it, especially with ammonia. What's happening is that even after you clean it, little particles break off and build up in the box over time. They continue to give off odors even if there are not clumps in the box. So, the best way to keep the smell down on top of scooping is to completely change and wash the litter box about once a week and have the box in a well ventilated room. The smell can also be more pronounced in small spaces where the air doesn't change over much, like in a laundry room or closed bathroom. Putting an air purifier in a room like that basically just recycles the stinky air in the room because it's already absorbed as much as it can. Air purifiers do, however, keep down litter dust, which can carry the odor through your house. Clay litters make a lot of dust, but are better at trapping odors. Silica crystal litters tend to stay put as far as dust goes, but they don't do much for the smell. Corn, newspaper, and walnut type litters are the worst for smell and should be completely changed every 2-3 days. No litter or air purifier can cover up the smell from an uncovered poop. Some cats just won't bury their doodies. I use Feline Pine. I was skeptical at first, but the rescues near me use it, which convinced me. It smells like a fresh forest when you first put it down. It's easy enough to scoop. It does make some dust when you pour it out fresh, but when the cats are in the box it doesn't make a lot of dust or track through the house on their paws. It's also very absorbent and neutralizes pee smells. Just like any other litter, it'll need to be completely changed every now and then. One last trick of the trade -- get a blacklight flashlight. Shine it on the walls and floor around the litter box to see if any pee particles sprinkled when they tinkled.
Anything with plasma, airwave, ozone etc is toxic. You have to research each model. I have a basic HEPA Honeywell because of this.
I love the ugly-ass Honeywell tower one i have. You can get washable filters too, which is a nice money saver. It's relatively quiet and powerful. Everyone should make at least one Corsi-Rosenthal box though because they are super effective!
I have a huge Honeywell tower that I loved for my old studio apartment, but now that I’m in a large house I honestly think corsi-Rosenthal is the best bang for your buck. They’re incredibly effective, cheap, good for large spaces, and customizable.
Pro tip: Buy two that use the same filters. You don't want to have to buy numerous different ones. That way you can buy filters easier in bulk. I run two honeywells that both use the H-hepa filters. I have one for my bedroom good for 200sqft then one for the kitchen and living room good for around 500sqft.
Mine is a Honeywell. Because I know I'll be able to continue to get filters (even if I do buy off brand ones, bc theirs are SO expensive). Standard filters is the way. The A+ prefilter is better than the standard softer A style, but both are good at catching cat hair (I vacuum it off regularly)
Honeywell makes standard styles/sizes (mine uses two R filters) and other companies use the same system so it's easy. You can also search by model number (ex hpa 200) These are what I bought last time: https://ebay.io/m/JRqZjg

Coway
Airmega AP-1512HH Mighty
Durable, effective, but struggles with strong odors.

Levoit
Vital 200S-P
Smart, quiet, great for dust, but some report filter smells.

Winix
5500-2
Great value, but noisy motor and Plasmawave issues.

Coway
Airmega Mighty
Durable, responsive auto-mode, but struggles with strong odors.

Winix
5510 & 5520
Good for allergies/pets, but carbon filter and Plasmawave issues.

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Coway - Airmega AP-1512HH Mighty