T800 WiFi (AT8U457-NWE)

Avoid Sans and Shark. Both are mediocre at best and use deceitful marketing. Blueair performs and is reviewed well. However, all of their units feature an always-on ionizer to charge the mechanical filtration media. Some people want to avoid this as there could be changes in air chemistry or possible negative health effects. Clean Air Delivery Rates (CADRs) are an important metric gauging cleaning effectiveness. For rooms in meters, ceiling height is very important. CADRs should be *at minimum* 3 times the room's volume in m^(3). I'll assume a height of 2.4 meters for calculations. * Room 1: 108 m^(3) × 3 = minimum 324 m^(3)/h CADR * Room 2: 66.48 m^(3) × 3 = minimum 200 m^(3)/h CADR For each room, you could buy the [Winix Zero-S](https://winixeurope.eu/en/air-purifiers/air-purifier-winix-zero-s/) (top CADR: 390 m^(3)/h) or the [Winix T800 WiFi](https://winixeurope.eu/en/air-purifiers/air-purifier-winix-t800/) (top CADR: 500 m^(3)/h). Both models have PlasmaWave, which is an optional bipolar ionizer. If you have pet birds, keep this off as it could harm them. Note: PlasmaWave turns back on after a power off/on cycle. Keep in mind the CADRs listed for purifiers apply to the highest airflow speed/setting only. Lower settings have lower CADRs which reduces cleaning effectiveness.

Okay... you STILL haven't told me where you're located, so I have to guess here. But something very oversized would be the Winix T800 WiFi or Winix 5500-2 if you're in Europe. Keep in mind most Winix units have PlasmaWave, a bipolar ionizer. If there are pet birds in your home, keep this *off* as it could harm or kill them. (NB: PlasmaWave is enabled by default after a power off/power on cycle.)

Freestanding air purifiers can't overcome walls and doors. You need one for each room or area. **Therefore we need each room's length x width x height to calculate Clean Air Delivery Rates (CADRs).** As for your questions: 1. Winix is good, but not the best. I'd generally say Coway is the best in terms of quality for consumer-grade units. 2. PlasmaWave is Winix's name for their bipolar ion generator. It can be turned on or off. PlasmaWave (in practice) seems to enhance Pollen CADR. I believe Levoit's PlasmaPro is also generates positive and negative ions. 3. HEPA vs. "True" HEPA is mostly marketing. What *is* important is listing the appropriate standard, the filter class (where applicable, like H13 or H14), and the filtration efficiency % at a particular particle size or sizes. 4. DIY Corsi-Rosenthal boxes can work very well, which typically use MERV 13 furnace filters. MERV 13 is a lower filtration efficiency than HEPA, meaning it captures fewer particles of certain sizes on a single pass. But... since MERV 13 is less restrictive, it can achieve more passes through the filter media faster which can result in higher CADRs. (Assuming sufficient airflow.) If you wanted to build a C-R box, I would recommend doing so with PC fans. Drawback: most C-R box configurations do not specify fine mesh pre-filters. Without these, the MERV filter media can clog sooner with coarse particulates such as visible dust and hair. 5. "Level of filter": I assume you mean filtration efficiency of a mechanical filter. Mold, fungus, pollen, and viruses are bioaerosols. They can be captured with HEPA, EPA, or certain MERV filters (generally MERV 13 and higher). EPA and MERV 13 filters are a lower filtration efficiency than HEPA, so it will allow more particles through on a single pass. But EPA and MERV 13 can achieve more filter passes and higher CADRs than HEPA with proper airflow for less money. 6. As for secondhand purifiers, that's up to you. Sometimes you can find items that are barely used. But it's also possible purifiers were used in highly polluted environments (e.g., lots of mold or post-fire remediation) or could have bed bugs inside. 7. The blue box looks like an air scrubber. These are meant for more challenging and large environments, e.g. during renovation, fire remediation, or serious mold remediation. Air scrubbers tend to be quite loud.

Winix shark and Honeywell are all well made and very efficient. Also its a huge plus if they have the mesh pre filter that you can wash/rinse as most of the pet dander will get caught in that vs. directly on the carbon or hepa filter which will save you some money on replacements. Winix hepa filters average 12 months for an average user but with pets im changing every 6 to 8 carbon filters are every 3 months or sooner depending on use kept in my room Shark "has a never change" (every 5 years replacement recommended) unit that my roommate has and that thing is awesome hasn't been 5 years yet but the pre filters have kept the hepa part clean (kept in living room) Honeywell is every 6 months i have two in the garage just because of dust accumulating due to non existent weatherproofing and it sucks walking onto a dusty room when you suffer from seasonal allergies. We have 2 dogs and a cat my ex adopted that somehow got left behind so the purifier is definitely a must. Hope this helps you

I have the first leviot on your list, it works good for pet hair and js fairly quiet. I dislike the winix because it has the plasmawave ozone stuff that is on by default. The winix is very strong but it makes my lings hurt if I forget to turn it off

Both of my Winix air purifiers started smelling like smoke, they are different models, cleaned weekly and filters changed regularly, I don’t recommend them.

I have the Winix. No issues to date. I don’t use the plasma wave feature.

We mainly use the winnix ones. They are fantastic.

Definitely recommend Winix. Australian and comes out top of various tests. (If you haven’t been warned- don’t buy Dyson) Super sensitive to more than just particulates and has a ‘pet filter’ that is changed monthly that goes around the main filter and prevents it getting clogged with dust. Helps to prolong its life if you have pets