Are Levoit Air Purifiers Good? Which Levoit Air Purifier Is Best?

Levoit sells more air purifiers on Amazon than almost any other brand. But the difference between a Core 300S in a 300-square-foot bedroom and a Core 600S in that same room is the difference between 2 air changes per hour and 5.

One helps. The other actually controls allergies, asthma triggers, and wildfire smoke particles. This guide covers every current Levoit model: the Core 300, Core 300S, Core 400S, Core 600S, Vital 100S, Vital 200S, and LV-H132. Each one gets a specific room size where it works and a room size where it fails.

What Makes Levoit Air Purifiers Different from the Competition?

Levoit built its reputation on three things: aggressive pricing, genuine True HEPA H13 filtration across the entire lineup, and a refusal to include ionizers in most models. That last point matters more than most buyers realize.

Many competitors in the under-$200 range include an ionizer stage. The Winix 5500-2 uses PlasmaWave ionization which can be disabled, but the feature is there. Levoit skips ionization entirely on the Core series. No ozone output. No surface particle redistribution. Just mechanical filtration through a pre-filter, True HEPA H13 media, and an activated carbon stage.

This matters because the California Air Resources Board (CARB) sets the strictest ozone limit in the United States: 0.050 ppm maximum. Every Levoit Core model is CARB certified. For asthma sufferers, this is not a nice-to-have. It is the single most important certification after AHAM CADR verification.

Levoit also uses a cylindrical filter design that pulls air through 360 degrees. A flat-panel purifier can only pull air through one face. The cylindrical design gives Levoit units higher CADR per dollar than most flat-panel competitors. A Levoit Core 300S delivers 145 CFM smoke CADR at $99. That is roughly $0.68 per CFM. Few competing units beat that ratio.

The trade-off is activated carbon capacity. Levoit units use a thin carbon-impregnated pre-filter sheet rather than a deep carbon bed. This removes light odors from cooking and pets effectively. It does not remove heavy VOCs, formaldehyde, or sustained chemical off-gassing. For that, you need an Austin Air HealthMate or an IQAir GC MultiGas with multiple pounds of activated carbon.

For most households without major chemical sensitivity issues, Levoit’s filtration profile is exactly right. True HEPA for particles. Enough carbon for daily odors. No ozone. Low noise. Low operating cost. That combination explains why Levoit dominates Amazon’s bestseller lists.

Levoit Air Purifier Model Lineup: Every Current Model Compared

Levoit currently sells seven distinct air purifier models across three product families. The Core series is the flagship line. The Vital series is the budget-conscious alternative. The LV-H132 is the compact desk unit.

Use the table below to compare smoke CADR, coverage area at both 2 ACH and 5 ACH, noise level, and annual operating cost across the entire Levoit lineup.

One number matters more than any other on that table: the coverage at 5 ACH column. Levoit (like every air purifier manufacturer) advertises coverage area at 2 ACH. That is the industry standard for general air quality maintenance. It is not the right number for allergy sufferers, asthma patients, or anyone buying an air purifier for a specific health reason.

For allergies and asthma, the American Lung Association and multiple peer-reviewed studies in the Journal of Allergy and Clinical Immunology point to 4 to 5 ACH as the effective minimum. At 5 ACH, a Levoit Core 300S covers 87 square feet, not the advertised 219. That is a small bedroom, not a master suite.

How Much CADR Do You Actually Need for Your Room?

Most buyers pick an air purifier by matching the manufacturer’s stated square footage to their room. That is the single most common sizing mistake. The manufacturer number assumes 2 ACH. If you need 5 ACH, the effective coverage drops to 40% of the stated figure.

The calculator below gives you the correct smoke CADR for your actual room and your actual health needs. Enter your dimensions and use case. The output tells you which Levoit model (or competitor) actually fits.

Core 300S vs Core 400S vs Core 600S: Which One Is Actually Right for You?

The Core 300S, 400S, and 600S share the same cylindrical True HEPA H13 design, the same VeSync app compatibility, and the same basic filtration architecture. The only meaningful difference is CADR. Higher CADR means faster cleaning and larger effective room coverage.

A Core 300S replacement filter costs about $25 per year. The Core 400S filter costs about $40 per year. The Core 600S filter costs about $55 per year. Over five years, a Core 300S costs roughly $225 total. A Core 600S costs roughly $525 total. The question is whether your room size and health needs justify the difference.

Use the table below to match your room type and health priority to the correct Core model.

Levoit Core 400S: The Best All-Around Levoit for Most Buyers

The Core 400S sits at the sweet spot of Levoit’s lineup. It delivers 260 CFM smoke CADR covering a 403-square-foot room at 2 ACH or a 161-square-foot room at the more demanding 5 ACH rate. That means effective allergy control for a standard master bedroom.

At 24 dB on sleep mode, this unit is effectively silent. For context, a whisper registers at 25 to 30 dB. A quiet library sits at 30 dB. The Core 400S at sleep mode is quieter than both. This makes it viable for light sleepers who need filtration overnight, which is when most allergen exposure occurs.

The VeSync app integration on the Core 400S is genuinely useful, not a gimmick. It shows real-time PM2.5 readings from the unit’s laser sensor. It graphs indoor air quality trends over hours and days. You can set schedules that automatically ramp fan speed during high-pollen hours (early morning) and drop to sleep mode at night. The Molekule Air Pro costs over $1,000 and uses unproven PECO technology that independent testing could not validate. The Core 400S costs $130 and uses True HEPA, which has decades of peer-reviewed evidence behind it.

For filter replacement, plan on swapping the Core 400S filter every 6 months under standard use. During heavy pollen season or wildfire smoke events, check it at 3 months. The filter wrap indicator on the VeSync app shows remaining filter life as a percentage based on fan speed and runtime hours. This is more accurate than a simple 6-month timer.

Budget Pick: Levoit Core 300S for Small Rooms

At $79 to $99, the Core 300S delivers 145 CFM smoke CADR with the same True HEPA H13 filtration as the more expensive models. It covers 219 square feet at 2 ACH or 87 square feet at 5 ACH. That makes it a small bedroom purifier, not a living room solution.

The Core 300S runs at 24 dB on sleep mode and draws roughly 22 watts on medium speed. Annual electricity cost is about $9 at 13 cents per kWh running 8 hours daily. Filter replacement is $25 per year. Total five-year cost: approximately $224 including the unit. For a dorm room, nursery, home office, or small bedroom under 150 square feet, this is the best value Levoit sells.

The non-S Core 300 (without WiFi) sells for about $79 and uses the same filter and motor. If you do not need app control or a PM2.5 sensor, save the $20. The filtration performance is identical. Both units use the same genuine Levoit Core 300 replacement filter.

Premium Pick: Levoit Core 600S for Large Rooms

The Core 600S is Levoit’s most powerful unit at 410 CFM smoke CADR covering 635 square feet at 2 ACH or 254 square feet at 5 ACH. It uses a larger cylindrical filter with more media surface area, which means both higher CADR and longer filter life at equivalent fan speeds compared to the 400S.

At $250, the Core 600S competes with the Coway Airmega 400 (400 CFM, $250) and the Winix 5500-2 (243 CFM, $150). The Core 600S beats the Winix on CADR and ties the Coway on price while delivering comparable filtration. The Coway Airmega 400 uses dual fans and covers slightly more area at 2 ACH (1,560 sq ft vs 635 sq ft), but that comparison is misleading: the Airmega achieves its 1,560 sq ft rating at a lower ACH rate. At 5 ACH, the two units are close.

The Core 600S includes a PM2.5 laser sensor with a color-coded display ring on the unit itself. Blue for good. Green for moderate. Orange for poor. Red for very poor. This gives you a quick visual read without opening the app. During a wildfire smoke event or high-pollen day, you watch the ring shift from blue to orange and know to close windows and bump the fan speed.

For anyone with a large master suite, open-plan living area, or combined living-and-kitchen space, the Core 600S is the correct Levoit. The Core 400S in a 500-square-foot room delivers only 2.6 ACH on turbo, which is below the 4 to 5 ACH target for meaningful allergy control. The 600S in that same space delivers 4.1 ACH. That is the difference between a purifier that helps and one that actually manages symptoms.

Levoit Vital Series: Budget Air Purifiers Worth Considering

The Vital 100S and Vital 200S are Levoit’s entry-level smart purifiers. The Vital 100S delivers approximately 130 CFM smoke CADR for $79. The Vital 200S delivers approximately 240 CFM for $90. Both include WiFi and VeSync app control. Both use the same True HEPA H13 cylindrical filter design as the Core series.

The trade-off is build quality and sensor accuracy. The Vital series uses a less precise PM2.5 sensor than the Core 400S and 600S. The auto mode responds more slowly to pollution spikes. The plastic housing feels lighter and less damped. None of this affects filtration performance. A Vital 200S at $90 delivers more CADR per dollar than any other Levoit. If your priority is maximum cleaning power on a tight budget, the Levoit Vital 200S is the best value in the lineup.

The Vital series also offers a pet-specific filter variant with a denser carbon pre-filter layer for odor control. If you have one cat or a small dog in a bedroom under 200 square feet, the Vital 100S with the pet filter is a solid $79 solution. For multiple pets or larger rooms, step up to the Vital 200S or Core 400S.

For comparison, the Honeywell HPA300 uses a flat-panel filter design and delivers 300 CFM smoke CADR with higher noise levels and no smart features. The Vital 200S at $90 with 240 CFM and app control offers a more modern feature set at roughly half the Honeywell’s price.

Are Levoit Air Purifiers Good for Allergies and Asthma?

Yes, with one critical caveat about room sizing. Levoit Core and Vital units use True HEPA H13 filtration that captures 99.97% of particles at 0.3 microns. Pollen grains range from 10 to 100 microns. Dust mite allergen particles range from 10 to 40 microns. Pet dander ranges from 2.5 to 10 microns. All of these are far larger than the 0.3-micron HEPA test particle size. The filtration itself is not the issue.

The issue is air changes per hour. The Asthma and Allergy Foundation of America (AAFA) certifies air purifiers based on their ability to reduce allergens in a specified room size at an adequate ACH rate. Most Levoit units are not AAFA certified (the RabbitAir MinusA2 and Coway AP-1512HH carry AAFA certification). Levoit filters are capable. The units are CARB certified for zero ozone. But the lack of AAFA certification means no third party has validated their allergy performance claims.

In practice, a Core 400S running in a 150-square-foot bedroom delivers roughly 5.2 ACH on turbo. That is sufficient for allergy control based on peer-reviewed research in the Journal of Allergy and Clinical Immunology. A Core 300S in a 200-square-foot room delivers about 3.6 ACH on turbo, which is below the evidence-based 5 ACH target. For allergy and asthma buyers, choose the Levoit model that delivers 5 ACH in your actual room, not the one whose advertised square footage matches your room.

What Levoit Air Purifiers Cannot Do

Levoit units use a thin carbon-impregnated pre-filter sheet. This is effective for light cooking odors, pet smells, and everyday household odors. It is not effective for VOCs, formaldehyde off-gassing from new furniture, or sustained chemical sensitivity needs.

Activated carbon removes gaseous pollutants through adsorption. The capacity is directly proportional to the mass of carbon in the filter. A Levoit carbon pre-filter contains less than 0.5 pounds of carbon. An Austin Air HealthMate contains 15 pounds of carbon and zeolite. The difference in VOC removal capacity is roughly 30 to 1. If you are buying an air purifier specifically for chemical sensitivity, paint fumes, new construction off-gassing, or formaldehyde, Levoit is the wrong tool.

Levoit units also lack UV-C germicidal irradiation. For mold spore inactivation, a Germ Guardian AC4825 includes a UV-C lamp alongside True HEPA. But UV-C in portable air purifiers has limited effectiveness because air moves past the lamp too quickly for meaningful inactivation. The EPA notes that UV-C is most effective in in-duct systems where exposure time is longer. For mold, source control (fixing the moisture problem) matters more than any air purifier technology.

Before You Buy a Levoit Air Purifier – Complete Checklist

Check off each point before making your Levoit purchase decision. These eight checks prevent the most common buyer mistakes.

How Long Do Levoit Filters Really Last?

Levoit recommends replacing filters every 6 months. In reality, filter life depends on three factors: daily runtime, fan speed, and local air quality. A filter running 24 hours per day on turbo in a home with two shedding pets will not last 6 months. A filter running 8 hours per day on auto in a clean, pet-free apartment may last 9 months.

The VeSync app on smart Levoit models tracks filter life as a percentage based on actual runtime and fan speed. This is more accurate than a calendar-based replacement schedule. When the app shows 10% remaining, order a replacement. Do not wait for the filter indicator light to turn red. Running a clogged filter reduces CADR, increases noise, and strains the fan motor.

Genuine Levoit filters cost $25 to $55 per year depending on model. Third-party compatible filters are available at lower prices but have not been verified for HEPA H13 efficiency. For allergy and asthma use, the $10 to $20 annual savings from a generic filter is not worth the uncertainty about filtration performance. The filter is the entire value proposition of an air purifier. Cutting cost here defeats the purpose of the device.

Levoit vs the Competition: Where Levoit Wins and Where It Does Not

Levoit’s strongest competitive position is the under-$150 price tier. The Core 300S at $99 and Vital 200S at $90 deliver True HEPA H13 filtration with smart features at prices that competitors struggle to match. The Blueair and Coway comparison reveals that both brands charge a premium for comparable CADR in their entry-level models. A Blueair Blue Pure 411a Max costs $130 for 141 CFM smoke CADR. The Levoit Core 300S costs $99 for 145 CFM. That is a 30% price advantage for equivalent performance.

In the mid-range ($150 to $300), the comparison tightens. The Winix 5500-2 at $150 with 243 CFM offers similar CADR to the Core 400S at $130 with 260 CFM. The Winix includes a washable activated carbon grid (AOC) and PlasmaWave ionization (which can be disabled). The Levoit has no ionizer stage at all. For buyers who want zero ozone by design rather than by disabling a feature, Levoit is the cleaner choice. The Winix 5500-2 remains a top-rated Amazon favorite with proven long-term reliability, but the Core 400S offers a more modern design with app integration and a PM2.5 display.

In the premium tier (above $300), Levoit does not compete directly. The Core 600S at $250 is the ceiling. For higher CADR needs or medical-grade filtration, buyers should look at Coway Airmega 400S, IQAir HealthPro Plus, or Blueair 605. The Holmes and Honeywell air purifier comparison shows both legacy brands focus on the budget and mid-range segment with flat-panel designs and higher noise levels. Levoit’s cylindrical design and quiet operation give it an edge over both in bedroom applications.

Levoit vs Other Brands: Trust and Durability Questions

Levoit is a relatively young brand compared to Honeywell (founded 1906) or Coway (founded 1989). The company was founded in 2017 and built its market position through Amazon’s platform. This raises a legitimate question: will Levoit still be selling replacement filters in 5 years? The answer, based on current trajectory, is almost certainly yes. Levoit is now one of the largest air purifier brands in North America by unit volume. Filter availability is not a concern for the Core series.

Long-term durability is harder to assess with a young brand. The Core series uses DC motors that are rated for 20,000+ hours of continuous operation. That is roughly 6.8 years at 8 hours per day. Early Core 300 units from 2019 are still running with original motors according to long-term user reports on Reddit and Amazon reviews. The cylindrical filter design also puts less strain on the motor than flat-panel designs because air enters from all sides rather than being pulled through a single face.

The VeSync app is a potential longevity concern. If Levoit discontinues app support or the app becomes incompatible with future phone operating systems, the smart features stop working. The purifier itself will continue to function using its manual controls. But auto mode, scheduling, and remote monitoring require the app. This is a risk with any smart home device, not unique to Levoit.

Is a Levoit Air Purifier Loud?

No. Levoit Core models are among the quietest air purifiers in their price class. The Core 300S and 400S measure 24 dB at sleep mode. The Core 600S measures 26 dB. All three are effectively silent in a bedroom at night. For comparison, the Honeywell HPA300 measures 38 dB at its lowest setting. That is roughly four times louder perceptually (a 10 dB increase is perceived as roughly double the loudness).

At turbo mode, Levoit units are audible. The Core 400S reaches 52 dB at maximum, which is comparable to moderate rainfall or a quiet conversation. This is not disruptive during daytime use but would be noticeable in a bedroom at night. The auto mode manages this by running the fan at the lowest speed needed to maintain the target PM2.5 level. In a closed bedroom with no active pollution source, auto mode typically settles at the lowest or second-lowest fan speed after 30 to 60 minutes of initial cleaning.

Can You Run a Levoit Air Purifier Continuously Without Damage?

Yes. Levoit Core and Vital units are designed for continuous 24/7 operation. The DC motor is rated for 20,000+ hours. Running continuously at auto or medium speed puts less wear on the motor than frequent on/off cycling. The main consequence of continuous operation is shorter filter life. A filter rated for 6 months at 8 hours per day will last roughly 2 months at 24 hours per day on turbo.

The energy cost of continuous operation is modest. A Core 400S draws 28 watts at medium speed. Running 24 hours per day at the national average rate of 13 cents per kWh costs roughly $32 per year in electricity. At sleep mode (5 watts), the annual electricity cost drops to about $6. ENERGY STAR certification on the Core 300S and 400S confirms these efficiency figures.

Do Levoit Air Purifiers Emit Ozone?

No. All Levoit Core and Vital models are CARB certified, meaning they have been tested and verified to emit less than 0.050 ppm ozone. This is the strictest consumer air cleaner ozone standard in the United States. Levoit units do not include an ionizer, UV-C lamp, or any other ozone-producing technology. They are purely mechanical filtration devices.

This is a meaningful differentiator. Many air purifiers in the same price range include an ionizer that can be disabled but not removed. The Winix 5500-2 has PlasmaWave. The Germ Guardian AC4825 has UV-C. The Blueair Blue Pure 211+ has an ionizer that is always on. Levoit has none of these. For asthma patients and anyone with chemical sensitivity, the absence of ozone-producing components is a safety advantage that costs nothing extra.

Why Is My Levoit Air Purifier Red Even Though the Air Seems Clean?

The red indicator on a Levoit Core 400S or 600S means the PM2.5 laser sensor is detecting elevated particle concentrations. Common triggers include cooking (even boiling water releases fine particulates), opening a window on a high-pollen day, burning a candle, vacuuming without a HEPA vacuum, or spraying aerosol products nearby. The sensor is measuring particles you cannot see.

If the indicator stays red for more than 30 minutes with no obvious source, check two things. First, clean the sensor lens with a dry cotton swab. The sensor port is on the back or side of the unit. Dust accumulation on the lens causes false high readings. Second, check that the pre-filter is not clogged. A clogged pre-filter restricts airflow, which reduces CADR and causes the sensor to read higher PM2.5 levels because the unit is not cleaning effectively.

Where Should I Place My Levoit Air Purifier for the Best Results?

Place it at least 12 inches from walls on all sides. The cylindrical design pulls air through 360 degrees. Blocking one side with a wall reduces effective intake area and CADR by 15 to 25 percent. The unit should sit in the same room where you spend the most time, typically the bedroom. Doors should be closed during operation. An air purifier cannot clean air in a room with an open door any more than an air conditioner can cool a room with an open window.

Do not place the purifier in a corner. Do not place it behind furniture. Do not place it under a desk or table where airflow is restricted. The ideal position is mid-room or against a wall with at least 18 inches of clearance on all accessible sides. For two-story homes, each floor needs its own unit. An air purifier on the first floor does not clean the air in a second-floor bedroom.

Can One Levoit Air Purifier Clean My Whole House?

No portable air purifier can clean a whole house. The physics does not permit it. Air does not move efficiently between rooms with closed doors. A single Levoit Core 600S running in a living room cleans the air in that living room and, to a lesser extent, connected open areas. It does not clean the air in a bedroom down the hall with the door closed.

For whole-house air cleaning, you have two options. Option one: place a correctly sized unit in every room where you spend significant time. For a three-bedroom house, that means three to four units. Option two: upgrade your HVAC system filter to MERV 13 and run the fan continuously during high-pollen or wildfire smoke events. A MERV 13 furnace filter captures 75% or more of particles in the 0.3 to 1 micron range per ASHRAE Standard 52.2. Combined with one well-placed portable unit in the primary living space, this approach covers both whole-house circulation and targeted room-level cleaning.

Do I Need to Replace Both the HEPA and Carbon Filter in a Levoit?

Levoit Core and Vital units use a single integrated filter cartridge that contains both the True HEPA media and the carbon pre-filter layer in one assembly. You replace the whole cartridge. There is no separate carbon filter to replace independently. This simplifies maintenance but means you cannot extend filter life by replacing only the carbon layer.

The outer pre-filter mesh is washable. Vacuum it every 2 to 4 weeks to remove visible dust and pet hair. This extends the life of the HEPA media inside by preventing large particles from prematurely clogging the fine filtration layer. Do not wash the HEPA or carbon layers. Water destroys the electrostatic charge on HEPA fibers and saturates activated carbon, rendering it useless.

Are Levoit Air Purifiers Good for Wildfire Smoke?

Yes, with the correct model sizing. Wildfire smoke consists primarily of PM2.5 particles in the 0.4 to 0.7 micron range. True HEPA H13 filters capture particles at 0.3 microns with 99.97% efficiency. The filtration technology is effective. The question is whether the unit’s CADR is high enough for your room at the sustained ACH rate needed during a smoke event.

During an AQI 150+ wildfire event, the EPA recommends running air purifiers on maximum fan speed and targeting 5 to 6 ACH. A Core 300S at 145 CFM delivers 6 ACH in a 72-square-foot room. That is a walk-in closet, not a bedroom. A Core 600S at 410 CFM delivers 6 ACH in a 205-square-foot room. That is a modest bedroom. For wildfire smoke protection in a 300-square-foot master bedroom, you need roughly 600 CFM smoke CADR. No single Levoit unit delivers that. The solution is two units or one very high-CADR unit from a different brand such as the Blueair 605 at 500 CFM.

Replace filters more frequently during wildfire season. A filter rated for 6 months under normal conditions may need replacement after 2 to 3 months of continuous wildfire smoke exposure. The carbon layer saturates with smoke odor compounds and the HEPA media loads with fine particulates faster than during normal operation.

Can I Use Essential Oils in My Levoit Air Purifier?

No. Do not add essential oils, fragrance pads, or any scented product to a Levoit air purifier. The oils coat the HEPA fibers, destroy the electrostatic charge that attracts particles, and permanently reduce filtration efficiency. The oil residue also attracts dust, which accelerates filter clogging. Levoit does not include an aromatherapy tray or essential oil pad on any Core or Vital model. This is intentional. Air purifiers are medical devices for particle removal, not scent diffusers.

If you want aromatherapy, use a separate ultrasonic essential oil diffuser in a different part of the room. Keep it at least 6 feet from the air purifier. The diffuser emits oil droplets that behave like ultrafine particles. Running a diffuser next to an air purifier forces the purifier to work against a pollution source you intentionally created.

Is the Levoit VeSync App Worth Using?

Yes, for three specific features. First, the app displays real-time PM2.5 readings from the unit’s laser sensor. This lets you see exactly how your indoor air quality changes throughout the day and in response to activities such as cooking or opening windows. Second, the app allows you to create schedules that automatically adjust fan speed. Set the unit to turbo for one hour when you typically cook dinner, then return to auto mode.

Third, the app tracks filter life as a percentage based on actual runtime and fan speed rather than a simple calendar timer. This is more accurate and prevents both premature filter replacement and running a filter past its useful life. The app is free and does not require a subscription. The non-S Levoit models (Core 300, Vital 100) lack WiFi and cannot use the app. The $20 premium for the S version is worth it for the filter life tracking and scheduling features alone.

Levoit Air Purifier Returns and Warranty: What to Expect

Levoit offers a 1-year limited warranty on Core and Vital air purifiers. This covers defects in materials and workmanship. It does not cover filter replacements (wear items), damage from using non-genuine filters, or damage from improper cleaning. The warranty process requires proof of purchase from an authorized retailer. Amazon purchases qualify. Third-party marketplace purchases may not.

Levoit’s customer service is responsive by email and phone during business hours. Replacement units for verified defects are typically shipped within 5 to 7 business days. The most common warranty claim is fan motor failure, which is rare based on Amazon review analysis. Less than 2% of verified purchase reviews mention motor issues across the Core series. If a unit fails, it typically fails within the first 30 days (infant mortality) or lasts for years. Test your unit thoroughly during the return window.

For most buyers, the Core 400S is the right Levoit. It delivers 260 CFM smoke CADR for $130, runs at a genuinely silent 24 dB on sleep mode, costs $40 per year in filters, and carries CARB certification with no ionizer. It covers a standard bedroom at allergy-grade 5 ACH and a living room at standard 2 ACH. The Core 300S is the budget alternative for rooms under 150 square feet. The Core 600S is the large-room solution for open-plan spaces.

Measure your room. Calculate your CADR requirement at the correct ACH rate for your health needs. Match the Levoit model to the requirement, not to the advertised square footage. That is the difference between owning an air purifier and owning one that actually works.