Winix C545 review

The C545 is making a solid comeback thanks to Costco and it remains a great option for those on a budget
Updated on May 10, 2024
Written by
Danny Ashton
Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.

Our verdict

With newer, more efficient mid-sized air purifiers on the market, the C545 still delivers great cleaning performance in rooms of up to 360 sq. ft. Boasting smart features not usually found at this price point, this air purifier also has an excellent $-per-CADR ratio. 


The bonded activated carbon filter is under-performing compared to others, but the True HEPA and removable pre-filter do a great job at removing the tiniest particles. Fairly quickly, too -26 minutes is not bad at all.


Plus, Winix has included a 2-year supply of extra filters in the box.

With a trajectory of over 50 years, Winix has a solid background in indoor air cleaning.

During the COVID pandemic, the South Korean brand gained a foothold in the U.S. market, attaining a solid place among the most preferred brands to improve Americans’ home air quality.

Winix produces budget-friendly, well-built, and high-performing air purifiers, with the corporate mission as its compass: “To deliver perfect products that are superior in Innovation, Performance and Style.” 

The Winix C545 is not the brand’s latest model (it was Energy Star-certified in 2019). In fact, the unit is only available as refurbished on the U.S. Winix website. But it is still trending and hyped by Costco, so we got curious about its performance. 

Besides traditional mechanical filtration, all Winix units have the built-in PlasmaWave® function, a by-polar ionizer that boosts cleaning efficiency. Ionization is a known controversial topic, so you’ll be pleased to know Winix units emit less than 0.01 ppm of ozone and are CARB-certified. However, one of the highlights of these air purifiers is that the function can be easily disabled. 

We have previously reviewed three Winix units, the 5300-2, 5500-2 and A231 and found solid results. So, we decided to get the C545 and put it to the test.

  1. In our home lab of 728 cubic feet, we light an incense stick to generate particle pollution and VOCs.
  2. We set up our trusted Purpleair Indoor Sensor with the latest Bosch gas sensor to track levels of PM1ug/m3, PM2.5ug/m3 and PM10ug/m3 and VOCs in the air.

  3. We switch the air purifier to its highest speed and measure how long it takes to get our room air quality down to PM1 level to 0.
  4. We use an energy meter to measure precisely how much electricity is used when running the unit at the lowest and highest fan speed settings.

  5. We track sound levels emitted by the air purifier at different fan speeds with the help of a commercial sound meter.

Read more about our testing process, and feel free to get in touch if you have any questions.

As always, we bought the C545 with our own money like regular consumers — no special treatment for us, no free Winix for HouseFresh. We prefer it this way. We are free to write unbiased reviews with an honest take on every unit we test.

The lowdown on the Winix C545

“The C545 is very similar to other Winix devices, like the 5300-2, and it’s just as good for removing particles. One thing that stands out is its app support, which you don’t find in other Winix models.
The fact that this device is sometimes sold cheaply at $99-$139 at Costco makes it an easy choice for those wanting a good air purifier on a budget.”
— Danny Ashton, HouseFresh Founder & Senior Writer

Before we dive into the detailed analysis of the unit, I’ve condensed the C545 highs and lows:

What we really like

All-round budget-friendly unit: low initial price and affordable long-term running costs.
Faster than more expensive units and still competitive, even when compared to newer models.
There are plenty of smart features, including app support for remote control, air quality readings and a light sensor.
An easy-to-navigate control panel that lets you switch off the ionizer at any time.

What we think could be better

It lacks a sturdy activated carbon filter. Instead, the C545 comes with carbon-impregnated fabric that needs to be replaced every three months.
Considering its size, it is not the quietest air purifier. When running at top speed, it generates 59 dB of sound.
The Winix Smart app could be improved.

HouseFresh rating:★★★★☆
Time to clean our 728 cubic feet test room (with the device running at top speed):PurpleAir Touch: 19 minutes
PurpleAir Zen: 27 minutes
Air purifier technology:Washable pre-filter, activated carbon filter, True HEPA filter and Plasmawave technology
Recommended room size (4.8 air changes per hour):360 sq. ft.
Clean air delivery rate (CADR):– Smoke: 232 CFM 
– Dust: 243 CFM 
– Pollen: 246 CFM
Dimensions (in inches / in cm):13.7W × 8.4D × 20.5H inches (35W x 21D x 52H cm)
Weight (in pounds / in kg):11 lbs (5kg)
Filter life:– HEPA filter: 12 months
– Odor filter: 3 months
Noise level in decibels (measured from 3 ft. away with a sound level meter):Speed 1: 36.1 dB
Speed 2: 39.2 dB
Speed 3: 43.1 dB
Speed 4: 59.2 dB
Electricity consumption in watts (recorded with an electricity usage monitor):Standby: 0.27 watts
Speed 1: 4.15 watts (4.46 with ionizer)
Speed 2: 6.6 watts (6.9 with ionizer)
Speed 3: 10.15 watts (10.49 with ionizer)
Speed 4: 51.30 watts (51.01 with ionizer)
Estimated running cost (electricity consumption + official filter replacement):$113.6 per year
Cost per CADR cfm (based on dust CFM as reported by AHAM):$0.53
Manufacturer’s warranty:2 years
Country of manufacture:

The best feature of the Winix C545: good $ to CADR ratio

Impressive 232 CFM (smoke) for $90 if you get it refurbished from Winix

As mentioned in the introduction, the Winix C545 can be bought refurbished at the manufacturer’s website for a mere $89.99. At Costco, on the other hand, you’ll find the new unit for $129.99. At the time of writing this review, I wouldn’t recommend buying from Amazon, as the C545 rises to over $170.

This price disparity makes my job harder when trying to compare the C545 with other units in the same price and cleaning power range. But I will try my best anyway.

The TaoTronics TT-AP003, for example, has a CADR of 226 CFM for $80 and features a pelleted activated carbon filter instead of the carbon-impregnated fabric. The same goes for the Levoit Vital 200S, which outperforms both the TT-AP003 and the C545 BUT it doubles in price ($190).

Now, things are more favorable to the C545 when comparing it against the Winix C535 and 5300-2, which can be found at $140 and $135, respectively. While neither of them have smart features, they share similar CADR and are all suited for 360 sq. ft. rooms. With those numbers in mind, it is clear that the  C545 offers a great $ to CADR ratio with extra smart features, not bad.

An old design that’s compensated with a few aces up its sleeve

The Winix C545 won’t stand out from the crowd for its looks, but it remains functional and offers smart features.

I’d venture to say classic rectangular-shaped air purifiers are making a comeback; they seem to be regaining protagonism after cylindrical units occupied the central stage for some time. Take, for example, the bold-looking Coway Airmega 150 or the sober and stylish SmartAir SA600

While the C545 is not among the latest releases in the industry, its rectangular body with a front air intake benefits from this trend.

The C545 comes in an all-white matte style with curbed edges, and is shorter and somewhat chunkier than the larger (and darker) 5500-2 and the 5300-2.

While newer Winiexes come with a magnetized tab to fasten the front cover, the front panel on the C545 is only attached to the body by clips. True, many units on the market rely solely on tabs (take the TaoTronics TT-AP003, for example, although it has an extra clip compared to the Winix). Still, it is worth pointing out the magnet feature ensures a more secure attachment.

The controls on the Winix C545 are straightforward and self-explanatory, so you can set it up and have it running without browsing the manual – although I usually take a look when unboxing a new unit. 

Instead of having just one button to cycle through the four different fan speeds, the C545 comes with arrow buttons to go back and forth between Auto Mode, four different fan speeds and Sleep Mode. 

The P – 3SEC legend stands for PlasmaWave®. To toggle the PlasmaWave® function, you’ll need to press the two arrows for three seconds simultaneously. The white LED light will indicate when it’s activated (light on) or deactivated (light off). By default, the unit will turn on with PlasmaWave enabled — I’m not a fan of that.

The Auto-mode in the C545 is possible thanks to the onboard air quality sensors, which will adjust the fan speed to tackle the level of pollutants detected. The LED light on the control panel will indicate the air quality in the room with a color-coded scale:

LED indicatorFan speed
🔴 red for polluted airTop fan speed
🟠 amber for fair airMedium fan speed
🔵 blue for good air qualityLow fan speed

That’s the industry-standard Auto mode, but the Winix C545 has an extra perk: it has a built-in light sensor that detects the amount of ambient light in the room. 

So, when in Auto mode, the moment you turn off the lights, the unit will turn to Sleep mode automatically. It will adjust the fan speed to the lowest, reducing noise output, and turn off all LED lights (except for the night mode light, though).

The Winix Smart app is usually reserved for top-tier air purifiers, such as the 9800 ($329). However, for tech enthusiasts on a budget, the C545 fits the bill — at least for North American users. 


As of January 2021, the Winix Smart app is no longer available in Europe or the UK due to the EU general data protection regulation. 

Therefore, for those based in Europe or the UK to whom app support was a key driver to getting the C545, I’d suggest checking out the Winix 5500-2, which comes with a remote control and a more robust pelleted activated carbon filter.

Or check out the Levoit Vital 200S, which offers remote access to the unit through the user-friendly Vesync app.

The Winix Smart app will let you create schedules, monitor indoor and outdoor air quality, track the filter’s life (and get alerts when it’s time to replace it), and logically control the unit remotely from wherever you are. As a bonus, you’ll also be able to command the Winix C545 with Amazon’s Alexa.

Although you get useful features and an enhanced experience with the app, I must say that it’s not the most intuitive one:

  • The signing-up process is tedious and a bit of a maze. Luckily, you just need to do this once.
  • You’ll have to grant the app access to your exact location. Winix claims this is just to provide outdoor air quality readings, but it won’t let you go through the pairing process without it.
  • The app sometimes loses connection with the unit. This can be easily fixed by closing and reopening the app, but it would be nice to see the Winix team permanently solve the issue.

Winix four-stage filtration: mechanical filters boosted by PlasmaWave®

The C545 comes with a robust True HEPA filter for particles but a weak activated carbon filter that falls short when dealing with serious VOCs.

Almost every air purifier comes with a single set of filters for you to get the unit up and running the moment you take it out of the box. Well, Winix went the extra mile with the C545 and added an additional set (which could last up to 12 months!) That’s right, when you buy a C545, you get two years’ worth of indoor air cleaning. Nice touch, Winix!

But then, there are some highs and lows to the C545 filters worth considering before making up your mind. Let’s start with the good. 

Like all Winix air purifiers, the C545 features AHAM-verified True HEPA filters capable of removing 99.97% of particulate air pollutants from the air as small as 0.3 microns. The filter traps dust, pollen, mold spores, dander, smoke particles, bacteria and more, boosted by the unit’s 246 CFM Clean Air Delivery Rate.

A second advantage of the C545 four-stage filtration is the removable pre-filter. Picking up on the rectangular-shaped air purifiers’ comeback, I’d say this type of pre-filter is one good reason behind it.

In budget cylindrical units, like the Leoivt Core series (200S, 300, 400S and 600S) or the Shark HP102, you usually find pre-filters fitted into the HEPA, which makes maintenance a lot trickier. But when you get a removable pre-filter, you will find that it’s much easier to stay on top of vacuuming and washing the mesh.

Winix suggests cleaning their pre-filters every two weeks. It’s pretty often, for sure. But by doing this, you extend the life of your HEPA, as the pre-filter traps larger particles such as lint, hair and pet fur that would otherwise clog the main filter faster.

The greatest downside of the C545 is the activated carbon filter.

Activated carbon filters trap VOCs and odors through adsorption: the gas molecules stick to the carbon, accumulating on its surface. The Winix C545 comes with a thin fabric impregnated with activated carbon, which is less effective when compared to a filter with pelleted activated charcoal.

Utilizing carbon-impregnated filters means there is a far smaller surface for the pollutants to adhere to. This leads to filters that become full (and ineffective) way faster than you’d like.

You can see how flimsy the activated carbon filter in the Winix 5300-2 and the C545 look when compared to the sturdier pelleted activated carbon on the Winix 5500-2 (right):


The C545 carbon filter needs replacement every three months. As mentioned above, you are covered for two years as the air purifier comes with eight of these. But while the unit and app show the HEPA filter’s lifespan, you’ll have to keep track of the activated carbon filter’s life cycle.

What you need to know about PlasmaWave®

The last stage of Winix filtration is the PlasmaWave® function. To put it in (very) plain terms, bipolar ionizers on Winix units alter the composition of airborne gas molecules and particles. These are either neutralized and turned into water (H2O) molecules or regroup into bigger, heavier clusters that are thus drawn into the ground (or any other surfaces in the house). 

As a disclaimer, I’m not 100% into ionization, no matter if it is unipolar or bipolar. Even when the air purifiers’ ozone emission is tested, such as in the case of the Winix units, introducing ions into the air can alter all kinds of airborne molecules and particles, such as fumes from ordinary cleaning products, and potentially produce dangerous by-products. In my view, compensating a weak activated carbon filter with an ionizer is not the smartest (nor safest) choice. 

Besides, those re-formed ion-particle clusters will deposit all around you, the HEPA filter won’t trap them all. As proof, you’ll notice more dust around the air purifier when the PlasmaWave® is on.


New filters always come in plastic wrappings. When you open the C545’s front panel, you’ll find the 2-years worth of filter supply, each individually packed. 

Remember to remove the plastic before placing the filters in the unit, but do so only for the set you’ll be using first. Put away the remaining ones with their packaging intact: the plastic protects the filters and prevents them from trapping any airborne particles while stored.

The Winix C545 cleared our test room in 26 minutes

Although somewhat old, the C545 can still compete with newer units.

At HouseFresh, we run a series of performance tests for every single unit we review. We like taking matters into our own hands to contrast manufacturers’ specs. We evaluate the air purifiers’ performance in real-life situations – mirroring the use you’d give the unit at home. 

Our first step is the air cleaning performance test. We light incense to generate particulate pollution in the same 728 cubic feet we test all units. Then, we measure the time it takes to remove the smallest PM1.0 particles using two Purple Air sensors: the Touch and Zen.

These were the results of the Winix C545:

Air cleaning performance results, compared

The C545 took 26 minutes to remove all PM1 particles from our 728 cubic ft. test room. This is above average on the spectrum of mid-sized affordable air purifiers.

With such speedy results, the Winix C545 outpaced more powerful and costly units like the Mila and Levoit Core 400S

While it didn’t outbeat the Levoit Vital 200S, it was three minutes faster than the TaoTronics AP-003. Similarly, upon comparison with other Winixes, the C545 felt behind the 5500-2 but trimmed off a whole minute of the non-smart but otherwise almost identical 5300-2. 

Noise levels results, compared

Cleaning efficiency is undoubtedly a key indicator of an air purifier’s performance. However, considering the air purifier will be running in the background for most of your time at home, the noise output can also be a decisive factor. 

By measuring the noise levels of the Winix C545, we found out the output was:

It’s not the quietest Sleep mode we’ve come across, but it is still silent enough to let you rest unbothered. At top speed, though, the C545 gets noisy. On the bright side, it comes with app support and the Winix Smart App allows you to create custom schedules. You can program or command the unit to do a deep air clean before you get home. 

Here’s how the Winix C545 compares to other units:

Coway Airmega 15055.6 dB33 minutes
TaoTronics AP-00354.2 dB26 minutes
Winix C54559.2 dB19 minutes
Levoit Vital 200S57.7 dB18 minutes
Smart Air SA60052.5 dB33 minutes

I know from personal experience that noise levels are subjective. Have a listen at our full sound test to see whether the C545 is too noisy for you:

The cost to run a Winix C545: $190.52 per year

An affordable air purifier with average long-term running costs.

1. Electricity costs = $77.79 per year

Air purifiers are like any other appliance: they add to the electricity bill. Energy costs are rising worldwide and are a pressing matter for some households. Knowing your energy consumption will help you plan your monthly expenses and decide if a unit is right for your home. 

Winix units have the PlasmaWave® feature; common sense would suggest that with the ionizer on, the unit would need more power to operate. However, we found no significant difference after measuring the energy consumption with the PlasmaWave® on and off. 

However, there is a leap when comparing the energy consumption at the bottom and top fan speeds, which range from 4.15 to 51 watts. There’s no mystery here: the fan needs more energy to pull in extra air at the top speed than on the lowest setting.

The C545 is the most efficient than other Winix devices, such as the 5500-2 (51 watts) and 5300-2 (53.46 watts) when running at top speed. 

However, units at a similar price point and similar CADR, like the Levoit Vital 200S or the all-affordable TaoTronics TT-AP003, consume far less energy annually ($37.84 and $30.48, respectively).

Coway Airmega 15031.55 watts33 minutes
TaoTronics AP-00336.5 watts26 minutes
Smart Air SA60060 watts33 minutes
Levoit Vital 200S44.55 watts18 minutes
Winix C54551.30 watts19 minutes

2. Filter costs = $59.99 per year

While you get replacement filters to last for two years with the Winix C545, air purifiers are built to last longer. 

The C545 uses the S Filters. It’s worth noting that, as an older unit, genuine replacement filters are not always easy to come by. When writing this review, for example, the genuine S Filters are missing from the  Winix Store at Amazon. However, they are available on the Winix web at $60 for a year’s worth. 

On the other hand—and for the same reason—plenty of generic Winix S filters are available on Amazon for $34.99, which is $17.50 a year for two HEPA and four odor filters.

PUREBURG C545 Replacement True HEPA Filter Set Compatible with WINIX PlasmaWave P150 and B151, C545 Air Purifiers, Part Number Filter C / 113050, Filter S / 1712-0096-00,H13 Activated carbon
  • ✅2-Pack High efficiency Replacement True HEPA Filter Set ( 2 True HEPA + 8 Carbon Pre-Filters)
  • ✅Compatible with WINIX PlasmaWave P150 and B151, C545 Air Purifiers , Part Number Filter C / 113050 , Filter S / 1712-0096-00
  • ✅H13 True HEPA capture 99.97% of airborne dusts PM2.5 down to 0.3 microns in size. Remove large and airborne particles, including dust, common pollutants ,Activated carbon Pre-Filter reduce Chemicals VOCs, tobacco smoke, PM2.5,common household bad smell
  • ✅Please replace regularly to keep your machine fresh and clean,For best results, remove the filter once a month and clean with a soft brush or gently vacuum.
  • ✅Top-Notch Quality Used for Maximum Customer Satisfaction Guaranteed,Change the PUREBURG replacement filter in minutes, no tools required; note: please remove the new filter from the plastic bag before placing it into it.

The C545’s replacement filters are not among the most expensive, but considering the odor/activated carbon filter is not exceptional, I wouldn’t consider them the most affordable either. Once again, when comparing with similar units, a two-set of filters for the TaoTronics TT-AP003 costs only $35, while the Levoit Vital 200S filter price rises no further than $60 a year.

Bottom line

With affordable long-term costs and featuring app support, the C545 is a solid option.

The Costco hype that is turning the old Winix C545 into a popular unit once again is not unfunded. 

It boasts a fine CADR score and a better cost-per-CADR ratio when compared to similar air purifiers. Besides, the unobtrusive design, removable pre-filter and a fair share of smart features make the unit very easy to live with.

As for the C545 shortcomings, I would point out two. First (and most significant to me), is the lack of pelleted activated carbon on the odor filters. Having to replace these every three months just to get subpar VOCs and odor filtration in return is not great.

It would be nice to see some improvements done to the Winix Smart App, especially in terms of UI and UX as it would be good to have an app that is more intuitive for the user. Needless to say, the company should also review the app’s privacy policy to comply with European and UK legislation.


We calculated yearly costs associated with running the Winix C545 for 24 hours a day, 365 days per year utilizing the latest average energy prices as reported by the Bureau of Labor Statistics of $0.174/kWh as of April 29th, 2024.

Winix C545 review - HouseFresh

With a trajectory of over 50 years, Winix has a solid background in indoor air cleaning.

Product SKU: 8809490583459

Product Brand: Winix

Editor's Rating:


  • An all-budget-friendly unit: low initial price and affordable long-term running costs.
  • Faster than more powerful units and competitive when compared to newer, more efficient models.
  • There are plenty of smart features: app support for remote control, air quality readings and light sensor.
  • Easy-to-navigate control panel that lets you switch off the ionizer at any time


  • It lacks a sturdy activated carbon filter. Instead, the C545 comes with carbon-impregnated fabric that needs to be replaced every three months.
  • The Winix Smart app could be improved.
  • It is not the quietest air purifier. When running at top speed, it generates 59 dB of soun

Last update on 2024-05-17 / Affiliate links / Images from Amazon Product Advertising API

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About the author

Danny Ashton

Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.

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