u/theorist9

I recently replaced my old bagged canister with a corded bagless upright (Shark Navigator Professional NV360).

I'm happy with it thus far, except for these two key downsides that accompany any corded bagless*: (a) the dust bin is smaller than a bag, so it requires frequent emptying; and (b) the dust cloud you get when emptying it.

That's why I think my cordless Samsung Bespoke Jet has a brilliant design—I just put the vaccum into the emptying/charging station, press a button, and the dust is whisked into a bag, which addresses both of those downsides.

And other brands of cordless sticks also have emptying stations.

Given this, I don't understand why this feature is only available (at least AFAIK) with cordless, but not corded, bagless models

Indeed, it seems that, with clever engineering, the emptying station might be also able to clear the dust from the HEPA filter, reducing clogging, which is another concern with bagless models.

*Though that clear dustbin does have an upside, since it alllows you to to see exactly how much dirt you are picking up, giving you direct feedback on which parts of your home require more or less attention. This is not something you can get from a bagged model (at least not conveniently).

My bedroom is 1680 ft^3, and thus needs a purifier with 1680/12 =140 CADR to give 5 ACH.

The problem is my bedroom is very quiet (it's below the 30 dB floor of my sound meter), and I'm a light sleeper, so I'd like a HEPA13 purifier (or combination of purifiers) that would come close to that CADR without raising the noise floor. And I'd like it to have some pelleted carbon filtration.

Thus far I've tried the Coway Airmega ProX (170 CFM on silent mode), BlueAir Signature (125 CFM on sleep mode) and Winix 5510 (55 CFM on sleep mode). Of these, only the Coway provides sufficient CADR, but only the Winix is sufficiently quiet. [Though it just developed a clicking sound on sleep mode, so I'll need to exchange it for a new unit.]

At this point, it seems my best bet is to use two Winix 5510's, which would give me 110 CFM. Since less dust is generated when you're sleeping (right?), I'm guessing that should be enough.

But I'm open to alternative suggestions.

Location: USA

Many air purifiers incorporate pelleted carbon granules.

Any carbon dust that may be created from the granules (which might happen if they are, say, jostled together during transport) is a health hazard if inhaled.

Thus it makes sense that most of the purifiers that incorporate carbon pellets put the carbon upstream of a HEPA or other particulate filter, which can then capture such dust. These include the Winix 5510, Coway Airmega ProX, IQ Air Health Pro Plus XE, AirPura (various models) and Austin Air Healthmate.

A notable exception, however, is the Alen Air Breathesmart series, which have no particulate filter downstream of the carbon. I.e., instead of prefilter/carbon/HEPA, they're prefilter/HEPA/carbon.

Presumably Alen Air knows what it's doing. But then again, so should Winix, Coway, IQ Air, AirPura, and Austin Air, all of which take the opposite approach, seemingly for good reason.

Thus is there any reason to be concerned about Alen Air's design? Any idea why they did it this way?

Note1: I'm referring specifically to pelleted carbon. I don't expect this would be a concern with bonded carbon filters.

Note2: I bellive the Oransi AirMend also doesn't have a particulate filter downstream of its carbon filter, since it's my understanding you can choose either their HEPA or their carbon filter, but not both. I'm not sure about the AllerAir models, or the BlueAir Signature.