WX100

We have the Winix WX100. An overlooked cost of these filters is the cost of replacement filters. Depending on your model, you may need separate charcoal and other stage filters. There are third party filters that are cheaper, some that may work as good as oem, others that are as ineffective. I'd look into the cost of these before committing to a filter. I'm always sus about reviews because they are often bought. Been some time since I last looked into this, but at a minimum I'd find something with HEPA and charcoal filter.

We probably don't run it as much as we should, maybe on average 2 hrs a day during peak heat in the afternoon. Can't remember what the recommended filter change timeline is, but it's different for each. The wx100 has a yellow filter sheet that collects a lot of hair, so that gets changed every 1-2 months. The charcoal and hepa filter we change every 6-12 months, but really whenever we feel like it depending on how it looks when we change that yellow pre-filter. I don't have many filters, just that one which we use to filter the kitchen/living room space. We also have dyson fans that double as filters, and some smaller portable off brand filters. Tbh, it's not like I have a device that measures the amount of dust particles in the air. Will only say, guests that come over say they don't smell the dog smell. There is also a light that comes on whenever the winix detects dust in the air and it seems to work (always turns red when the pup walks by lol)

IQ Air is one of the best as the Health Pro Plus Xe I think does a good 300ish CFM while also having I think 15 pounds carbon pellets + related to absorb odors/VOCs/smoke etc. Although if your allergies are purely particulate based you can get 400CFM of particulate coverage for like 90 bucks with a DIY CR box /Corsi Rosnethal box.  (A 30 dollar box fan taped to a set of 4 merv 13+ filters is as much or more particulate coverage than you will get from any 300-400 dollar air purifier pretty much.)  So you don't need to spend 1,000 dollars on a unit to get good air.  If smoke/odors/gasses and allergies related to those issues then definitely IQ Air.  And it's one of the best units anyway.   But for physical allergens many units do very well, units from Winix, Levoit and Coway all perform really well and close to each other.  In particulate coverage.  So I like Levoit as they are simple and effective and good value for what you get.  So a Levoit core 600 is a powerful unit with 390 or so CFM for 280 bucks or so.  Has air quality monitor as well.  If you want an ionizer you can get the plasma pro version, but be careful as ionizers can cause respiratory distress in some.  So some Winix + Coway units have ionizer that can be toggled on/off but you have to look closely.  As well Coway uses an antibacterial fungicide on their filters in low/safe levels but if you have allergies relating to that then I'd go Levoit or Winix,  but they are also good units otherwise. Dyson are known for being very quiet and have good air sensors but they don't move much air.  I think it moves as much as the Levoit 200 you already have...but it costs like 800 dollars more.  So not really worth the cost if you just want the best particulate coverage.  Alen is a good brand too that is kind of good at both particulate and VOCs, with their best filter.  And they have a lifetime warranty if you stay in filter replacement program.  Austin Air are also 2nd best for VOCs,  but don't move much air in terms of particulate coverage.  I think it's a good idea to have a unit good vs VOCs even if it's not your top priority so maybe an Alen 45i or 75i + a Levoit Core 600 or similar priced Winix.  Alens are also quieter, but don't move as much air as Levoit/Winix/Coway.  As slowly air flow is better at absorbing VOCs/gasses with the carbon pellets.  Levoit has some in their filters but not nearly as much as those other units more tailored for VOCs, so a Levoit can still help a little in that regard likewise Winix + Coway also I think.  But Alens are a little better for VOCs a little quieter and a little slower, but still decent at CFM speed.  IQ AIr best units also good at both and better than the Alen by a lot.  Austin Air very good VOC, kinda slow for particulates.   So again, depends what types.of allergies/needs.  But for just particulates, with a little help on VOCs...Levoit, Winix, Coway all pretty great.  Or even a CR Box which at 90 bucks and 400 CFM rivals or outdoes must about any unit for particulate coverage.  Even 1 box fan with a merv 13 filter in front/behind it..can do about 150 CFM...pretty close to what the vital 200 does.  As box fans are big,.cheap, energy efficient...and move a lot of air.  That's essentially all most purifiers are.  A filter + a smallish fan to move the air around.  You pay more for air quality sensors, filter replacement reminders, apps and various others features.    But lots of units can capture particulates every well,.even 90 dollar CR Boxes + related.  So something like a Levoit Core 600/Levoit Everest Air/Winix + a unit for VOCs like Alen might make sense.  (Alens are sortof thin so a hallway might work.)  Or get the IQ AIR if you have the money to spend.. but you will still want another unit too for total CFM coverage.  Lots of options...so what features are most important to you ?    Another really thin unit is Rabbit Air, as you can even hang them on a wall...however they also don't move much air.  Maybe if you put two, on one each wall, but that's pricey as they are a bit Dyson-esque in paying like 250 bucks or so for only I think 113CFM. So two of them would be around 500 bucks for only 226 CFM...so definitely not good value.  But space wise can be useful in some instances perhaps.  

Just throwing this out there to help with allergies. As you said you have lost your elder dog (rip buddy). Is this new pup the same breed? Just because he was immune to the other dog don’t mean that this one brings new allergies. But it can signify that it’s a different breed that kid can not tolerate. Each breed sheds differently from the other. Some more then the rest. Just a thought. I’m allergic to cats and dogs. But more so cats. We have the homedics 5-1 that really helps. But it’s recently gotten so loud that we are making the switch to the Winix brand. I would recommend staying away from the Lrg round units. Go with a rectangular one.