When you reach that time of year when the weather traps you inside your house, it’s hard not to quickly realize that your indoor air quality may not be the best.

According to the World Health Organization, 4.3 million people a year die from exposure to household air pollution. That’s primarily because about 3 billion people cook and heat their homes using solid fuels such as wood and coal, which produces high levels of indoor air pollution. These families, mostly in undeveloped nations in Asia and Africa, can suffer life-shortening effects from pollutants such as fine particles and carbon monoxide.

But even in the U.S., people can have serious health reactions to household pollutants. Dust, dander and mold can worsen allergies, asthma and other respiratory illnesses. Not only that, but aging upholstered furniture can shed unhealthful flame retardant chemicals that mingles with house dust. The science is still emerging on how these affect people. But the EPA says indoor air pollution is among the top five environmental health risks.

To combat this, many people turn to air purifiers, which use various technologies to cleanse the air. Many units claim to deal with odors, smoke, germs and more. The most advanced units will even combat volatile organic compounds (VOCs) and other respiratory irritants that arise from adhesives, paints and household cleaning products.

Reducing dust, dust mites and pet dander remains challenging, because dust mites and pet dander are bigger particles that can fall to the floor, escaping filtration, according to the EPA. So there’s no getting around taking other steps, such as dusting, vacuuming and airing out a room. That said, an air purification device can still help cleanse indoor air, especially of smaller particle pollutants.

Which air purifiers work best seems to be in the eye — make that the nose — of the beholder. The EPA does warn against using ozone-generating air filters, because ozone is itself a contaminant, and these types of filters often aren’t effective anyway. Beyond that, the agency counsels that no cleaner will deal with every scenario.

There is one certification to look for, that of the American Home Appliance Manufacturers (AHAM). Their “Verifide” certification means air filters have been independently tested to check manufacturer claims. One more acronym to know: CADR, for Clean Air Delivery Rate. This number will tell you a little bit about how powerful the machine is and if it will be effective in the space you’re trying to purify.

Additional Clean Air Delivery Rate (CADR) ratings are available at the AHAM site. These show how efficiently the machine processes specific pollutants, based on scales set up for tobacco smoke (the range is 10 to 450); for dust, (10-400) and for pollen (25-450). The higher the number the better, but know that most household units fall into a mid-range. You can use these numbers to compare across units, but there’s no need to get too bogged down in them.

If you have the time, the EPA has an excellent set of publications dealing with indoor air pollution and air cleaners.

If you don’t have that kind of time, here are a few of the better choices on the market based on customer reviews and Consumer Reports’ testing:

 

Whirlpool Whispure Air Purifier, HEPA Air Cleaner, AP51030K

Like most of the filters we’ve selected for this list, the Whispure does a good job, some say great, on its core mission of picking up dust, pollen and smoke air pollution. It grabs particles down to .3 microns and is AHAM certified to purify the air in a room up to 500 square feet in size, making it big enough to handle a living/dining room combo.

Consumer Reports gives it an “excellent” rating for pollutant removal on its “high” setting and a “very good” for removal when on “low.”

Customers praise it for being powerful and some wish it were a little quieter, though it is among the quietest tested by Consumer Reports.

Pros: Does the job, well-tested and vetted by consumers, reasonable retail price of around $300. Top marks from Consumer Reports.

Cons: It won’t be the most lovely item in the room.

 

Blueair 403 HepaSilent Air-Purification System

This purifier did win a design award, in Sweden. But does it fill your filtration needs?

Probably, yes. It cycles the air of a 365 square foot room five times every hour — which is standard for this group of air purifiers — capturing particles down to .1 micron, which the smallest particle brag you’ll see. Most other purifiers, including the others listed here, capture particles down to .3 microns.

Getting down to .1 micron may matter to you if you’re trying to catch smoke particles and odors, the smallest particles around. Still it could be a distinction without a difference when it comes to microscopic air saboteurs. Even smoke particles clock in at 1 micron, or 10x larger than the smallest particles this filter can capture. Dust, dander and pollen particles are even bigger, generally 5-30 microns or more. Who knew?

Like all the units here, the Blueair verifiably picks up dust, pollen and smoke, because it’s been AHAM certified, and it’s Energy Star rated.

Pros: Consumers report that the Blueair 403 is quiet, effective and energy efficient. It is Energy Star certified and AHAM rated, indicating its claims have been tested by outside reviewers.

Consumer Reports gives it an “excellent” rating for removing dust, pollen and smoke when on its highest setting, though removal was only “fair” on the low setting. (The bigger Blueair 503 rated better on low setting.) A light alerts you when its time to change the filter.

Cons: Retailing around $500, this model is on the pricier side; apparently there’s an upcharge for this sleek design and its ability to snatch tiny particles out of the air.

Blueair 503 HepaSilent Air-Purification System

This larger Blueair unit can cleanse the air in a 580 square foot area, suitable for a larger living space, such as a living/dining or great room.

We mention it because its larger, still looks cool and performs like the 403 and gets an even better review from Consumer Reports for having “good” removal of pollutants at the low setting. The big drawback, now you’re looking at 650 clams. But if you like the design, and the assurance of a positive CR review…

 

Honeywell True HEPA Allergen Remover

No discussion of air purifiers would be complete without some mention of Honeywell, which makes a bazillion of them. Here’s the deal, though, models come and go so fast, it’s hard to pin them down when researching. The one shown here is the HCA200, which promises to cover a 310 square foot room. It’s a smaller version of the HCA300 (465 sf of coverage), which garnered Consumer Reports’ top scores, “excellent” for high setting and “very good” for the low setting for removing dust, pollen and smoke.

Given the mostly positive customer reviews of this model online, we’re gambling this one works well too. But a caveat, it’s a smaller unit.

One asthmatic pet owner raved on Amazon: “I was a major skeptic only because there are so many on the market. How can you really know you have the best or the right one? 5 days later I’m amazed to see how much dirt it has picked up.”

Even buyers who were less than thrilled with some features dubbed this air filtering machine “useful” and effective at tamping down allergies.

Pros: Effective, similar larger model is top-rated by Consumer Reports, can be set on a timer for 2, 4 or 8 hours. Filter replacement warning light. A reasonable retail price of $199. Choice of black or white casing.

Cons: Customers didn’t have much good to save about the carbon pre-filter, which is supposed to reduce odors.

 

Honeywell 50250-S 99.97% Pure HEPA Round Air Purifier

Another good point about buying Honeywell is that all of its air filters are AHAM tested and many are Energy Star certified as well, as is this one.

This is another model that’s been well-received and well-rated by Consumer Reports for dust, pollen and smoke removal. This unit is larger than the HCA200 above, with a capacity to cover a 390 square foot space.

Customers like that the HEPA filter is long-lasting 3 to 5 years, and it can be vacuumed in the interim.

The big design difference here: The unit captures surrounding air over 360 degrees. This expands your placement options, depending on your needs.

Pros: “Excellent” pollutant removal at high setting. An indicator light to alert you when the filter needs cleaning. Reasonably priced at $200-ish.

Cons: Noise rated as “poor” — because it makes too much. Some consumers have noted some irritation with the noise of this unit, though others say they aren’t bothered. This one won’t win any beauty contests, but then you didn’t pay for prize-winning looks either.

 

Winix FresHome Model P450 True HEPA Air Cleaner with PlasmaWave

This unit promises to get rid of odors, as well as smoke, pollen, pet dander and dust. It clears the air of pollutants down to .3 microns in a 450 square foot room.

It’s AHAM certified and boasts a triple layer of filtration. While other purifiers have two layers, a charcoal and HEPA filter, the Winix adds it’s own “Plasmawave technology,” which Winix says doesn’t just trap particles but “safely breaks down odor causing particles, allergens” and other pollutants, making them easier to whisk away.

Consumer Reports rates it as “excellent” at high setting, and “fair” at its low setting for removing dust, pollen and smoke.

Pros: A clever, slim design and a good buy at around $200 retail. Gets the job done at the high setting, and has garnered many positive customer reviews for picking up odors, as well as allergens, possibly because of the triple-layer filtration.

Sleep setting is apparently suitably quiet.

Cons: Some consumers say the unit is flimsier than they expected and louder than they like on higher settings (though Consumer Reports gave it a “good” for noise level at the high setting). Some say previous Winix models seemed sturdier. The “fair” rating for pollutant removal at the low setting is concerning. However, most of the air purifiers that Consumer Reports tested came in with only “good” or “fair” scores for effectiveness at the low setting.

 

Rabbit Air MinusA2 SPA-780A

People report this is everything they want from their filter — effectiveness, quiet and an unobtrusive look.

Here’s a typical comment, this one from a dad who credits this filter with solving his kids’ allergies: “I kept coming back to the rabbit. It was more than what I wanted to spend, but that was the only thing keeping me from buying it. I am glad I did… It was easy to get up and running and I like the fact that all the filters were individually wrapped. It is a bit bigger than what I expected, but that is a good thing. I ran it all night and when I woke up, my boys rooms smelled clean and they didn’t have stuffy noses.”

However, this machine was not tested by Consumer Reports, nor could we find an AHAM certification for it. That’s not to say it doesn’t work well, just that there was less documentation to consider, so we cannot pronounce it to be the Dyson of air purifiers.

But it seems worth a look, with its cool design and customizable filter system. This slender unit also has great reach, covering 815 square feet — your great room and adjoining kitchen, maybe even half the house.

Pros: HEPA technology, non-bulky, can stand or be wall-mounted, very quiet and almost silent in sleep mode, according to buyers.

Large capacity and unobtrusive design and many loyal fans (no pun intended).

This Rabbit has four customized filters: Pet Allergy, Germ Defense, Toxin Absorber and an Odor Remover and a six-layer filtration system, all in 7 inches. Top filter can be vacuumed and filters changed every 1-2 years.

Cons: Pricier at about $550, though it does cover more area; may not be certified by the AHAM — we couldn’t find a listing for this unit.