The 7 Best Air Purifiers of 2026 (And Why the Square-Footage Claim Is Wrong)

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Our quick picks

Below you get the reasoning, the specifications worth comparing, and the limitations we found.

The square-footage number on an air purifier box is the most misleading figure in the category, and understanding why it is misleading is most of what you need to know to buy a good one.

Here is the problem. Manufacturers usually derive that coverage figure from a single air change per hour — the machine moves a volume of air equal to the room once every sixty minutes. That is a legitimate calculation, and it is also nearly useless for allergies, smoke, or pet dander, because particles are being generated continuously while the purifier works. What actually helps is four to five air changes per hour, which is the rate most indoor-air researchers point to for allergy relief. Run the arithmetic and a purifier advertised for 1,800 square feet is really a good fit for something closer to 400.

That single correction eliminates most buying mistakes. The second correction is learning to look for CADR — clean air delivery rate — and specifically an AHAM Verifide mark, which means an independent body tested the numbers rather than the marketing team writing them. Between those two ideas you can evaluate any purifier on the market in about ninety seconds.

This guide covers seven air purifiers that hold up under that scrutiny, sized from a bedside unit to a machine that can handle an open-plan main floor. We also cover the part of the category that deserves a warning rather than a spec comparison: purifiers that clean air by generating ozone, which is a genuine respiratory irritant and something to avoid rather than optimise. If humidity is also part of your indoor-air problem, our guides to the best dehumidifiers and the best humidifiers cover the other half.

Quick picks

• Best overall: Levoit Core 600S-P — AHAM Verifide CADR, really high airflow, and a filter ecosystem that is easy and cheap to keep fed.
• Best for very large open spaces: Coway Airmega (3,120 ft² rated) — dual-intake design with a washable pre-filter, built for open-plan main floors.
• Best for medium rooms with app control: Blueair Blue Pure 311i Max — quiet, simple, and one of the lowest-hassle filter designs in the category.
• Best for fine particles and gases: AirDoctor AD3500 — UltraHEPA media plus a substantial carbon stage, for wildfire smoke and VOC-heavy homes.
• Best for small rooms and bedsides: Medify MA-14 — H13 media, a quiet low speed, and a footprint that fits a nightstand.
• Best value for a mid-size room: PuroAir 240 — strong independent test documentation for the money and a sensible three-stage filter.
• Best for pet hair: Levoit Vital 100S-P — a wide U-shaped inlet that swallows fur instead of matting it across a pleated filter.

One safety issue to settle before anything else: ozone

Some air purifiers clean air by producing ozone, marketed as “activated oxygen,” “energised oxygen,” or simply as an ozone setting. Ozone is a lung irritant. Breathing it can trigger coughing, chest tightness and shortness of breath, and it is particularly bad for people with asthma. Public health agencies including the US Environmental Protection Agency have been consistent on this point: at concentrations that comply with public health standards, ozone is not effective at removing indoor air pollutants, and at concentrations that would be effective it is unsafe to breathe.

Ionisers and plasma-type purifiers are a related but separate question. These charge particles so they clump and settle, and many produce some ozone as a by-product. Some models are certified to California’s ozone emission limit, which is the strictest widely applied standard in the US, and those are reasonable. But an ioniser is not a substitute for filtration — it moves particles out of the air and onto your surfaces rather than capturing them. The sensible approach is simple:

• Buy a purifier whose primary mechanism is a mechanical HEPA filter, not ozone or ionisation.
• If your purifier has an ioniser or plasma mode, you can leave it switched off — the filter does the work.
• Avoid anything sold as an ozone generator for occupied rooms outright. Ozone machines have legitimate professional uses in sealed, unoccupied spaces; a bedroom you sleep in is not one of them.
• If you or someone in the house has asthma or another respiratory condition, this is worth raising with a doctor rather than resolving from product reviews, including ours.

Every purifier on this list is a mechanical filter machine first. Where a model includes an ioniser, we say so, and the recommendation stands on the filter performance with that mode off.

Our shortlisting process

We built this list from current Amazon listings, manufacturer specifications, published CADR and AHAM Verifide data where it exists, and the pattern of what large numbers of verified buyers repeatedly praise and complain about. We did not run these machines in a test chamber and we are not going to imply that we did. What we did was check whether the performance claims are independently verified, convert coverage claims into realistic room sizes at a useful air-change rate, and weight buyer feedback toward complaints that recur across hundreds of reviews.

Every pick holds a customer rating of 4.5 stars or better. We excluded several heavily marketed purifiers whose only performance evidence was the manufacturer’s own testing, and we excluded models whose primary selling point was ionisation or ozone for the reasons above. We also gave weight to something reviews rarely mention at purchase time and always mention a year later: the cost and availability of replacement filters.

What to know before you buy

CADR is the number that matters, and AHAM Verifide is the mark that makes it trustworthy

CADR, or clean air delivery rate, expresses how much filtered air a purifier delivers per minute, measured separately for smoke, dust and pollen. It is the closest thing this category has to an honest single figure, because it combines airflow and filter efficiency — a machine can have excellent media and a weak fan and still perform poorly, and CADR catches that.

AHAM Verifide is a voluntary certification program run by the Association of Home Appliance Manufacturers in which an independent laboratory verifies the CADR a manufacturer claims. It is not a quality award; it simply means the numbers were checked. Given how freely coverage figures are invented in this category, that is worth a great deal. Several picks on this list carry it, and where a model does not, we say so.

Converting coverage claims into a real room size

If a listing gives you CADR, the quick rule is: multiply the smoke CADR by about 1.55 to get the square footage that machine will clean at roughly 4.8 air changes per hour in a room with standard eight-foot ceilings. That is the figure you should compare against your actual room.

If a listing only gives you a coverage number, assume it was calculated at one air change per hour and divide it by four or five. A purifier advertised at 1,500 square feet is realistically a 300–375 square foot machine for allergy purposes. This is not a scandal — the one-change calculation is a recognized convention — but it is why so many people buy a purifier and feel like nothing changed.

True HEPA, H13, and the phrases that mean nothing

A true HEPA filter captures at least 99.97% of particles at 0.3 microns, the size that is hardest to catch. H13 is a European classification roughly equivalent to, and in some specifications slightly stricter than, true HEPA. Both are meaningful.

“HEPA-type,” “HEPA-like,” “99% HEPA” and “HEPA-style” are marketing constructions with no defined standard behind them. If a listing avoids saying “true HEPA” or naming an H-class, assume the filter is less capable than it sounds. Every pick on this list uses genuine HEPA-class media.

Worth knowing too: the 0.3 micron figure is a worst case, not a floor. HEPA media captures both larger and smaller particles more efficiently than it captures 0.3 micron ones, which is why the common claim that HEPA filters “let viruses through” is wrong. Smaller particles are caught by diffusion rather than interception, and the net efficiency goes back up.

Carbon matters more than people think, and it is where corners get cut

HEPA media captures particles. It does nothing at all for gases — cooking smells, paint fumes, VOCs from new furniture, the smell of smoke as distinct from smoke particles. That job belongs to activated carbon, and the amount of carbon is what determines whether it works.

A thin carbon-impregnated mesh bonded to the HEPA filter will knock down odors for a few weeks and then saturate. A genuine carbon stage weighs a noticeable amount and is measured in pounds. If odor control is one of your reasons for buying, look for the carbon weight in the specifications; if the manufacturer does not publish it, that is usually because there is not much to publish.

Noise is the reason purifiers get switched off

A purifier that is too loud to sleep beside gets run on its lowest setting or not at all, at which point its rated performance is irrelevant. The figure to look for is the decibel level at the lowest speed, and the figure to be skeptical of is the one at the highest.

Roughly: under 25 dB is actually unobtrusive in a bedroom. Around 30 dB is a soft hiss you will notice in silence but sleep through. Above 50 dB is a fan you cannot ignore. Because CADR is measured at the highest speed, a purifier you will only ever run at speed one is effectively a much smaller machine — which argues for buying one size larger than you need, so that a comfortable low speed still moves enough air.

Filter cost is the real cost

Filters are consumables, typically replaced every six to twelve months depending on use and air quality, and over a few years they often add up to more than the machine did. Before buying, check that replacement filters are actually stocked for the model you are choosing, and check whether the manufacturer sells them as a single combined cartridge or as separate pre-filter, HEPA and carbon stages. Separate stages usually work out cheaper, because a pre-filter you can vacuum or wash extends the life of the expensive HEPA layer considerably.

Be wary of subscription-only filter models and of very new brands whose filters may become hard to find. A purifier you cannot buy filters for in three years is disposable.

The 7 best air purifiers

1. Levoit Core 600S-P — best overall

Levoit has quietly become the default answer in this category, and the Core 600S-P is the reason why. It is AHAM Verifide, which immediately puts it in a smaller group than most of its competition, and its CADR is high enough that it can hold a truly large living room at a useful air-change rate rather than the fictional one. The three-stage filter separates pre-filter, HEPA and activated carbon, which is the arrangement that keeps running costs sensible.

It is also a well-judged appliance in the boring ways that matter. The app works, the particle sensor is responsive enough that auto mode actually tracks cooking and vacuuming rather than reacting ten minutes late, and the filter is cheap and universally stocked. Customer rating sits at 4.7 stars across an enormous number of reviews, which for a product with this many units in the field is meaningful signal rather than noise.

Why it made the list: it is the machine that does everything adequately and several things well, at a size that fits the room most people actually want cleaned. Verified performance figures, low filter cost, responsive auto mode and wide availability are a combination almost nothing else on this page matches at once.

The part that annoys people: it is physically large — this is a substantial cylinder, not a discreet box, and in a small bedroom it dominates. On its highest speed it is loud, as any machine moving this much air must be; if you intend to run it beside your head at night you will be using a lower speed and losing some of the capacity you paid for. The carbon stage is competent but not generous, so for serious VOC or paint-fume problems the AirDoctor below is the better tool. And the auto mode responds to particles, not gases, so it will not ramp up for an odor.

Who it is for: most people. Living rooms, large bedrooms, open-plan spaces up to a few hundred square feet at a real air-change rate, and anyone who wants verified numbers rather than claims.

See the Levoit Core 600S-P on Amazon →

2. Coway Airmega (3,120 ft² rated) — best for very large open spaces

When the space is big — an open main floor, a combined kitchen and living area, a large studio — the honest answer is usually two mid-size purifiers rather than one big one, because two machines in two places clean faster than one machine in a corner. But if you want a single unit, this is the one, and Coway’s dual-intake design is why. Air is drawn in from both sides rather than one face, which raises effective airflow for a given footprint and makes placement less critical.

The HyperCaptive filtration system combines a washable pre-filter with HEPA and carbon stages, and the washable pre-filter is a valuable detail: it is the part that clogs first, and being able to rinse it instead of replacing it materially reduces what the machine costs to run. Smart Mode adjusts fan speed to measured air quality. Customer rating is 4.6 stars, and Coway has a long track record in indoor air quality rather than a recent pivot into it.

Why it made the list: it is built for the case the rest of the list handles badly. Dual intake plus high airflow plus a washable pre-filter is the right architecture for a large space, and the long-term filter economics are better than the sticker suggests.

Where it disappoints: the 3,120 square foot rating is a one-air-change figure, so apply the correction from earlier in this guide — think of it as a serious several-hundred-square-foot machine, not a whole-house solution. It is expensive, both up front and for filters, and it is a large object that is hard to hide. Some models in this range include an ioniser; if yours does, you can leave it off with no loss of filtration. And a machine this size is not a bedroom purifier — it is too large and too loud at useful speeds for a small room.

Who it is for: open-plan main floors, large living rooms, and anyone who would rather buy one good machine than manage two.

See the Coway Airmega on Amazon →

3. Blueair Blue Pure 311i Max — best for medium rooms with app control

Blueair’s design philosophy is different from everyone else’s on this list, and for a lot of homes it is the better one. Rather than forcing air through dense media with a powerful fan, Blueair combines a lighter mechanical filter with an electrostatic charge applied to incoming particles, so the filter can be less restrictive while still capturing effectively. The practical result is a machine that is notably quiet for its output and uses very little electricity.

The 311i Max is the medium-room member of that family, rated for a couple of thousand square feet at one air change — call it a few hundred square feet in real terms. Built-in sensors and app control let you set schedules and watch the particle count, and the filter is a single wrap-around cylinder that takes about ten seconds to change with no tools. Customer rating is 4.5 stars.

Why it made the list: quietness and simplicity, which are the two attributes that determine whether a purifier stays switched on. The single-cylinder filter is the least annoying replacement design in the category, the running power draw is low enough to be truly irrelevant to your bill, and the sensor-plus-app combination is well executed rather than bolted on.

The drawbacks: the electrostatic charging means this is technically not a pure mechanical filter, and while Blueair units are certified to California’s ozone emission limits, people who want strictly passive filtration should know that going in. The carbon in the standard filter is a light coating rather than a substantial bed, so this is not the machine for a home with a persistent odor or VOC problem. Filters are proprietary and not cheap. And the coverage rating deserves the same fourfold haircut as everyone else’s.

Who it is for: bedrooms and medium living spaces where noise matters most, and anyone who wants scheduling and air-quality history without fighting a bad app.

See the Blueair Blue Pure 311i Max on Amazon →

4. AirDoctor AD3500 — best for fine particles and gases

This is the specialist pick, and it earns that position on two fronts. Its UltraHEPA media is rated to capture particles substantially smaller than the 0.3 micron standard HEPA benchmark, which is relevant if your concern is wildfire smoke, traffic-related ultrafine particulate, or a household member with significant respiratory sensitivity. And unlike most of its competition it pairs that with a substantial activated carbon stage rather than a token coating, so it addresses gases and odors instead of just particles.

AirDoctor pitches the AD3500 at large rooms — bedrooms, kitchens, living rooms — and the airflow supports that claim reasonably well once you apply the standard correction. Customer rating is 4.7 stars, and the recurring theme in positive reviews is smoke and odor performance specifically, which is exactly what the design targets.

Why it made the list: nothing else here does gases properly. If you live somewhere with a wildfire season, next to a busy road, above a restaurant, or in a house that has just been renovated, the carbon bed is the difference between a purifier that helps and one that only appears to. The finer media is a real advantage for ultrafine particles.

The catch: it is expensive to buy and expensive to feed — the filters are among the pricier in the category and the carbon stage is the part that needs replacing most often if it is doing its job. AirDoctor’s performance claims are largely based on its own commissioned testing rather than AHAM Verifide certification, which does not mean they are wrong but does mean they are less independently checked than Levoit’s. Denser media also means the fan works harder, so it is not the quietest machine at a given output. And the UltraHEPA advantage is real but incremental — do not expect a night-and-day difference over a good standard HEPA unit for ordinary dust and pollen.

Who it is for: wildfire-smoke regions, VOC-heavy homes, recent renovations, and households where respiratory sensitivity makes the extra capability worth the running cost.

See the AirDoctor AD3500 on Amazon →

5. Medify MA-14 — best for small rooms and bedsides

Most small purifiers are small because they are cheap, and they perform accordingly. The MA-14 is small because it was designed for a small room, which is a different thing. It uses H13 media, rated tighter than standard true HEPA, has three fan speeds with a quiet lowest setting, and covers a modest area properly rather than a large area badly.

The controls are physical and obvious — fan speed, timer, filter indicator — with no app to configure and nothing to pair. For a nightstand, a nursery, a home office, or a dorm room, that is a feature rather than an omission. Customer rating is 4.7 stars.

Why it made the list: honesty about size. A purifier rated for around 470 square feet at one change is a realistic 100–120 square foot machine, and that is precisely a bedroom. Buying a correctly sized small unit and running it continuously beats buying an oversized one and running it on speed one. The quiet low setting means it will actually stay on overnight, which is the whole point.

Where it falls short: it is a small machine and will not clean a living room — do not stretch it. The carbon layer is a light coating, so odor control is limited; this is a particle machine. There is no air quality sensor and no auto mode, so it runs at whatever speed you set, which means you are the sensor. And on its highest speed it is audible in a way you will not sleep through, so plan on speed one or two for overnight use and set it running earlier in the evening.

Who it is for: bedrooms, nurseries, home offices, dorm rooms, and anyone who wants buttons instead of an app.

See the Medify MA-14 on Amazon →

6. PuroAir 240 — best value for a mid-size room

PuroAir is a newer name than most of this list, and it has taken an unusual route to credibility: rather than leaning on coverage claims, it leans on published third-party laboratory testing of what the machine actually removes. For a brand at this price point that is a meaningful differentiator, because independent test documentation is exactly what the cheap end of this category normally lacks.

The machine itself is a straightforward and sensible three-stage design — pre-filter, HEPA, activated carbon — sized for a mid-size room such as a bedroom or a modest living room. Customer rating is 4.5 stars, and the consistent positive theme is that it noticeably helps with pet dander and general dust rather than that it feels luxurious.

Why it made the list: it is the pick for someone who wants a second or third purifier without doubling their budget. Running two correctly-sized mid-range purifiers in the two rooms you actually occupy will do more for your air than one premium machine in the hallway, and this is the model that makes that strategy affordable.

What owners complain about: PuroAir is not AHAM Verifide, so its CADR is not independently certified in the way Levoit’s is — the lab testing it publishes covers filtration efficiency rather than clean air delivery rate, and those are different claims. As a younger brand it has a shorter track record on long-term filter availability, which is the risk with any new entrant. Marketing language around “cleaner air in minutes” is optimistic for any purifier in a real room. And the carbon stage is modest, so treat odor control as a bonus rather than a feature.

Who it is for: anyone buying a second unit, anyone on a tighter budget who still wants real filtration, and pet households wanting coverage in more than one room.

See the PuroAir 240 on Amazon →

7. Levoit Vital 100S-P — best for pet hair

Pet households break normal purifiers in a specific way: fur and dander mat across the face of a pleated filter, airflow collapses, and the machine quietly stops working long before the filter indicator says anything. The Vital 100S-P addresses that directly with a wide U-shaped air inlet rather than a narrow grille, which spreads intake over a much larger area so hair accumulates loosely instead of forming a blanket. There is also a dedicated Pet Mode that runs the fan in a pattern intended to lift settled dander off surfaces.

Underneath the pet-specific design it is a conventional and well-executed Levoit: AHAM Verifide, three-stage filtration, cheap and widely available filters. It is sized for a bedroom to mid-size room. Customer rating is 4.7 stars, and pet owners specifically are the loudest positive voices in its reviews, which is the signal you want here.

Why it made the list: it solves a real problem rather than a marketed one. Anyone who has pulled a felted mat of fur off a purifier filter after two months understands why intake geometry matters, and this is the mainstream model that took it seriously. The verified CADR and low filter cost mean you are not paying a premium for the pet feature.

The downside: Pet Mode stirs air deliberately, which means it also stirs dust, and some people find it counterproductive in a bedroom — it belongs in a living room during the day rather than beside your bed at night. The pre-filter still needs vacuuming regularly; the inlet design slows clogging, it does not prevent it. It is a mid-size machine and will not handle a large open plan. And if you have no pets, the Core 600S-P above is the better buy at a similar level of quality.

Who it is for: homes with shedding dogs or cats, and anyone who has already destroyed a purifier filter with fur.

See the Levoit Vital 100S-P on Amazon →

Placement changes performance more than most upgrades

A correctly placed mid-range purifier outperforms a badly placed premium one, and placement costs nothing.

• Put it in the room you occupy, not the hallway. Purifiers clean the air in the room they are in. Air does not circulate between rooms nearly well enough for one machine to serve a floor.
• Give it clearance. Most units need six to twelve inches of clear space around the intake and outlet. Pushed against a wall or into a corner, a purifier partly recirculates its own clean output and throughput drops.
• Raise it if you can. A purifier on a low table often performs better than the same unit on the floor, because it is drawing from the air layer you actually breathe rather than the layer below it.
• Keep it near the source, not near the door. For cooking odors, close to the kitchen. For pet dander, near where the animal sleeps. For pollen, near the window you open.
• Close the windows while it runs. An open window resupplies outdoor particles faster than any consumer purifier can remove them. Ventilation and filtration are both good; doing them at the same time wastes the filtration.
• Run it continuously on a low or auto setting. Purifiers are not appliances you switch on when the air feels bad. Steady operation at a moderate speed produces far better results than bursts at maximum.

Maintenance that actually matters

• Vacuum the pre-filter monthly. This is the single highest-value habit. The pre-filter catches hair and large dust, and keeping it clear protects the expensive HEPA layer and maintains airflow.
• Do not wash a HEPA filter unless the manufacturer explicitly says it is washable — almost none are. Water destroys the media structure, and a washed HEPA filter looks fine and filters badly.
• Replace on schedule, not on appearance. Filter indicators count runtime hours, which is a reasonable proxy. A HEPA filter that looks grey is still working; a carbon filter that looks fine may be completely saturated, because saturation is invisible.
• Wipe the sensor. Particle sensors get dusty and start reading high, which makes auto mode run the fan constantly. A gentle wipe or a puff of air at the sensor port fixes a purifier that has mysteriously become loud.
• Keep the box or note the model number. Filter part numbers are model-specific and easy to get wrong a year later.

Common mistakes

• Trusting the square-footage number. Divide it by four or five, or work from CADR instead.
• Buying one machine for a whole house. Two correctly sized purifiers in two occupied rooms beat one large one in a hallway, almost always.
• Expecting it to fix a mold or moisture problem. A purifier captures airborne spores; it does nothing about the damp surface producing them. That is a repair and dehumidification job.
• Running an ioniser or ozone mode for extra cleaning. The filter is the machine. Leave the extras off.
• Ignoring the low-speed noise figure. The speed you will actually use determines the performance you will actually get.
• Forgetting filter cost before buying. Over three years, filters frequently exceed the purchase price. Check availability and whether stages are sold separately.
• Putting it in a corner. Blocked intake means a machine running at a fraction of its rating.

Frequently asked questions

Do air purifiers actually help with allergies?

For airborne allergens — pollen, pet dander, dust that has been disturbed — yes, and the research is reasonably consistent that HEPA filtration in the bedroom reduces symptoms for many people. The important caveats are that it needs to be the right size for the room, running continuously, and in the room where you spend time. It will do nothing for allergens that live in your mattress and carpet rather than the air, which is why purifiers work best alongside washing bedding hot and vacuuming with a sealed HEPA vacuum. If your symptoms are significant, this is worth discussing with a doctor rather than solving with equipment alone.

Should I run it all the time?

Yes. Particles are generated continuously by cooking, walking, pets and outdoor air leaking in, so intermittent operation means the air is only clean intermittently. Modern purifiers on low or auto draw very little power — typically comparable to a light bulb — and continuous moderate operation is both quieter and more effective than occasional bursts at maximum.

Where should I put an air purifier in a bedroom?

Reasonably close to the bed but not pointing at your face, raised off the floor if you have a surface for it, and with clear space around the intake. Six to ten feet from the head of the bed is a good compromise between cleaning the air you breathe and not being bothered by the airflow or noise.

Will a purifier help with wildfire smoke?

A HEPA purifier is one of the effective things you can do indoors during a smoke event, and a unit with a substantial carbon stage helps with the smell as well as the particles. Two things matter: close windows and doors and run the purifier continuously on a high setting, and expect to replace filters much sooner than normal, because smoke loads them quickly. Oversizing the machine for the room is a real advantage here.

Do I need one purifier per room?

For the rooms you actually spend hours in, yes — usually the bedroom first and the main living room second. Air moves between rooms far too slowly for one machine to serve several, and a closed bedroom door effectively isolates a purifier in the hallway completely. Two mid-size units usually beat one large one for the same money.

Are HEPA filters washable?

Almost never, and washing one ruins it. The fine fiber structure that does the filtering is damaged by water, and a washed filter dries looking normal while performing much worse. Pre-filters are frequently washable or vacuumable and should be cleaned regularly; check your manual, and if it does not explicitly say the HEPA layer can be washed, it cannot.

Do air purifiers remove carbon monoxide or radon?

No, and this is an important limitation to be clear about. Activated carbon does not meaningfully capture carbon monoxide, and no consumer purifier addresses radon. Carbon monoxide requires a detector and, if triggered, fresh air and emergency help — never a purifier. Radon requires testing and, if elevated, a mitigation system. Treat a purifier as a particle and odor device, not a safety appliance.

How long do purifier filters last?

Typically six to twelve months for the HEPA stage under normal residential use, and often less for the carbon stage if odor control is being used heavily. Heavy dust, pets, smoke events and continuous high-speed operation all shorten that considerably. Vacuuming the pre-filter monthly is the most effective way to extend the life of what sits behind it.

Our call

If you want one recommendation, the Levoit Core 600S-P is the purifier to buy. It has independently verified performance figures, enough airflow to hold a real living room at a useful air-change rate, cheap and universally available filters, and an auto mode that works. For most homes it is simply the right answer.

From there the picks divide by problem. Large open-plan space: the Coway Airmega, with its dual intake and washable pre-filter. Bedroom where quiet is everything: the Blueair Blue Pure 311i Max. Wildfire smoke, VOCs or a recent renovation: the AirDoctor AD3500, which is the only pick here with a serious carbon bed. A small room done properly: the Medify MA-14. A second or third unit without a second budget: the PuroAir 240. Shedding pets: the Levoit Vital 100S-P.

Whatever you choose, do two things. Divide the advertised coverage by four or five before deciding whether it fits your room, and check what the filters cost before you buy rather than a year later. Those two habits will get you a better outcome than any amount of comparing feature lists.

For the rest of the indoor climate picture, see our guides to the best dehumidifiers, the best humidifiers, and the best space heaters.

Also worth reading: our guide to the best mattress toppers.

Also worth reading: our guide to the best weighted blankets.

Also worth reading: our guide to the best blackout curtains.

Also worth reading: our guide to the best ceiling fans.

Also worth reading: our gift guide for dog owners — what solves the owner’s actual problem, and the toy-safety rules worth knowing.