> "I think what we're trying to do is pull back a little bit from the CADR metric," he said. "Not everyone needs an enormous CADR, has huge rooms or incredibly dirty air."
> Several experts told Marketplace the CADR is the most important metric and an internationally recognized benchmark.
> "CADR is what you want to know, period," said Francis (Bud) Offermann, an indoor air quality researcher who has helped develop test methods for the performance of portable air cleaners with the American Association of Home Appliance Manufacturers (AHAM).
CADR may well be "what you want to know, period" when it come to air filtration. However it might NOT be all you want to know when buying a consumer product. If the filter is quiet and effective and good looking and only ramps up when needed, is this not in some ways a better PRODUCT than a box fan running at full speed all the time with a filter taped to it?
I think it would be interesting to run a purifier in a normal house for 48 hours and see what the steady state particulate levels settle at around the house. I would guess that over a certain threshold CADR, there might not be that much difference. Room air circulation combined with a good enough CADR might even be more important, which is what Dyson claims.
For all the people in the bay area worried about the next fire season, CADR is probably the most important since there's an extreme source of particulates. I'm just not sure that's the final say on air purifier effectiveness in less extreme conditions.
Viruses are generally too small for even the best filters, but the droplets that carry them are well within what a HEPA filter can manage.
The average diameter of coronavirus particles is around 0.12 μm. The diameter of the envelope is 0.08 μm and the spikes are 0.02 μm long.
A P100 HEPA filter will remove as much as 99.97% (for P95 it is 95%) of all airborne particulates with an aerodynamic diameter of 0.3 μm, and particles both larger and smaller are removed with an efficiency greater than 99.97%.
Even if viruses are smaller than 0.3 μm, they are an easy target for HEPA filters.
The masks we all wear are primarily droplet guards, not air filters, they catch splatter that might float. All of the air that blasts out the back and escapes is barely going to be diverted by another mask after it’s already escaped the other mask and has had time to exist, right?
I guess for my threat analysis, if you’ve already invited them inside your house and they’ve stayed long enough that you think their breath particulates are floating in the air, you’ve already lost the war, so to speak.
Probably just a few minutes will be all that matters, I suspect. If you like, go take a walk and wait for the droplets to land?
That's why ventilation is important if you are sharing a room with other "external" people.
These people come from civil engineering backgrounds where air filtration requirements might often be thought of from an industrial or at least much larger than a domestic/micro loft scale.
Having any air filtration at all at a smaller scale is generally just great if you replace filters often enough, don't aren't near industry or aren't in a city, don't cook at home often... Even then, a smaller air purifier's going to do an awesome job if you let it run regularly.
Same as "processor speed is all that matters"... well, not. I honestly would gladly pay more for a QUIET computer (they are become more available).
It does seem that they're comparing apples to oranges. Of course if you optimise for one metric ignoring the trade-offs and extra features: fixed air flow for a single given particulate removal measure, the cheapest solution that arrives at and maximises that metric is going to come out on top.
But if you consider:
- Hepa vs Merv - Additional carbon filter - Remote control - Multiple pivot options - Multiple power options - In built sensors and real-time reporting for small particles, large particles, no2, volatile organics, temperature and humidity - smaller horizontal footprint - Smartphone integration + remote operation - noise footprint
then "shock", you have to pay more to have those features! (and they do provide value).
Dyson certainly offers "I like to burn my money" options like many other companies, and they're not priced cheaply, but it's dishonest to review a sports car and a utility van on the metric of boot space and proclaim a "one little trick they don't want you to know about" type headline.
Also, I haven't seen anyone else tackle it: what the hell is up with this "corona-virus protection" hints and claims in this article? Is that not enough to set off most people's internal alarms that the article is quackery?
Looks do matter, and at least for our decor, there isn't really much choice. We pick our furniture based on how it mathes our interior decor, why would an air purifier be any different if it's out and on all the time?
It's not surprising a 3-in-1 product isn't very good at (at least) 1 of those functions.
> It has a remote
Check
> It looks attractive
Check. It's invisible.
> sound profile
Check. Furnace fans are in the garage.
> analyze the temperature, humidity, and air quality
Nope. But purpleair will sell it to your for $175.
> oscillates
Check. Covers entire flat.
Having said that, oscillating fans annoy me because the degree of rotation is almost never controllable. I have very rarely seen fans with a clip underneath that causes the rotation to reverse direction.
I suspect that you're fairly lucky.
That said yes it was expensive, but it replaced needing a fan for cooling and an air purifier, and if I needed a heater it could have done triple duty.