Air Purifier MAX with True HEPA

FWIW you need to measure individual rooms and target the best or most frequent areas. The size of the house is somewhat irrelevant as these air purifiers work with smaller spaces. Additionally air purifiers are marketed very deceptively if you are not familiar with CADR or AC metrics. Some manufactures list square footage “up-to” a certain square footage. This is typically for 1 Air change rate an hour. For a decent filter in a room (that is used) you need at least 3 air changes for hour but the recommendation is 4.8 so I use 5 for my measurements. Will smaller air purifiers work? To some degree yes but they will take a very long time to clear out existing particulate matter from the air. So how does CADR fit in? It’s the actual measured rate at which clean air can be delivered by the unit. By knowing the CFM (cubic feet per minute) of the CADR (clean air delivery rate) you can size accordingly. budget constraints can definitely put pressure on your decision making but I would try to go with the larger most cost affordable option to get a better option. My suggestion would be the levoit Everest. Most places have it for $500 but for some reason BBY has them on clearance right now for $299. This single unit my provider more filtered air than the individual smaller units combined. I just added 2 more. Remember over sizing is ok but undersizing will take much longer to clear out existing particulate matter not accounting for new load. Additionally the Everest has wheels and can be easily moved. It is advertised as up to 2656 sq ft. This is for 1 air change. However we can see to hit the target 4.8 air changes to filter the air means this should really be used in a room no larger than 550 sq ft. If that doesn’t work in the budget focus on the smaller rooms for sure and size the air purifier accordingly. Otherwise you may feel like you wasted money and that air purifiers are not working. For what it’s worth I have shark never change (not great for large rooms but nice for bedrooms) the levoit plasma core 600 for our living room, the levoit Everest is in 4 bedrooms (price per performance while on clearance is hard to beat outside of DIY), a smart air blast mkII, and a 20x20 CR Cube with an 16” drum fan (garage) If you’re crafty a DIY Corsi Rosenthal cube can out perform every one of these for under $200 but the aesthetics are not very appeasing. (Hence why mine is in the garage) TLDR - sizing is important and advertising is not straightforward in regards to actual coverage.