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Winix C535 (Winix Zero) True HEPA Air Purifier

Winix C535 is an air purifier that can clean air in the room rapidly thanks to its three-stage filtration system and the additional boost it gets with the ionizer turned on. Large filters allow this air purifier to perform at the highest level.

Design and Size

The build quality of the Winix C535 model is top-notch. The Winix C535 is white, except for the control panel on top of the device, which is black.

The color and appearance can fit into many rooms, such as the bedroom, living room, kitchen, etc. The device is easily transported thanks to the handle located on the top of the device. At the top of the device is the control panel with all the buttons, indicators, and sensors. I will say more about the control panel later in the following Winix C535 review. One thing that I need to mention is the power cord; its length is standard.

Control Panel – Initial Operations

There are buttons on the control panel for complete device control. Besides, there are all the necessary indicators and sensors that the Winix C535 has. The buttons are standard press buttons; they don’t respond on touch. They react to smooth pressure.

The buttons do not light up. However, you will hear a beep sound at each press. The control panel buttons are the on or off switch, the select mode button, the PlasmaWave technology on or off button, the fan speed button, and the timer button.

In addition to the buttons, there are indicators above each button.

When the Winix C535 is facing you, on the left side, next to the edge of the device, is a filter reset indicator as well as light and odor sensors.


Air enters on the front of the device, through the cover, and from the sides. After that, the air is filtered through a pre-filter, then through a carbon filter, and finally through a true HEPA filter. If PlasmaWave is on, the air will be additionally filtered. The filtered air comes out on the top of the device and is directed upwards.

Size and Dimensions

The air purifier weighs 14.7 lb. Although a little heavier than average air purifiers on the market, the C535 is easily transported from location to location thanks to the carrying handle. The dimensions of the device are 15 x 8.2 x 23.6 inches.

Winix C535 Features

Auto Mode

This mode regulates the speed of the device based on air pollution in the room. If the air quality is low, auto mode will automatically switch the fan speed to turbo mode, and vice versa if the air quality is good. In addition to the smart sensor, auto mode is also affected by the light sensor. This means that if the room is dark and the device is operating in auto mode, the C535 will automatically switch to sleep mode.

I used the Winix C535 for a while in the bedroom, and I can say that I was delighted, mainly because of auto mode. Because literally all I need to do is turn on the device, and I can comfortably forget about it. Besides, the remote controller was always at hand, so I could turn it off whenever I wanted. In the evening, when I go to sleep, auto mode on the C535 automatically switches to sleep mode, so I didn’t even notice it, and the air quality in the room was always exceptional.


This advanced technology produces hydroxyls to neutralize bacteria and viruses. PlasmaWave is an ionizer. It can be switched off or on as desired by the user.

Air Quality Indicator

The air quality indicator will display the current air quality by illuminating specific colors depending on what air quality is detected via the smart sensor.

Winix C535 air quality indicator will display three states. When the indicator lights up blue, then the air is good, orange means the air is not good, and when you see red, then the air is horrible.

Smart Sensor

The smart sensor detects odors in the air. Based on that, it determines the speed of the device if auto mode is on

Based on the smart sensor’s detected air quality, the air quality indicator will illuminate specific colors. I have described this process above in the air quality indicator section.

Sleep Mode

When sleep mode is on, the Winix C535 is barely hearable. The device produces almost inaudible sound, 40.8 dBA. I used the Winix C535 in the bedroom, and I can say that I didn’t even notice that the device is there, especially in combination with auto mode, which will automatically turn on sleep mode when the room gets dark. At the end of the review is the section about the volume that the Winix C535 produces at all speeds; check it out.


The Winix C535 uses a timer as an advanced option. The timer can be set to 1h, 4h, and 8h. A timer is a useful option if you like to use an air purifier for a particular period. After a set timer is up, the air purifier will turn off automatically.

Remote Control

The Winix C535 air purifier comes with a remote controller with included batteries. The remote controller controls the device from a remote location at a maximum of 20 feet from the device.

With the remote controller, we can use the following options: power (on/off), auto mode, changing fan speed, and turbo mode.

Check Filter Indicator

The check filter indicator will light up when it is time to replace the filter.

It will notify you when it is time to replace the True HEPA filter and the carbon filter.

Room Coverage and CADR Rating

Winix C535 is designed for rooms up to 360 sq. ft. AHAM verified for five clean air changes per hour in 360 sq. ft. space. Proper for medium to large size living rooms.

Winix C535 Filtration

The Winix C535 uses three-stage filtration. The primary filter is the True HEPA filter, the second stage filtration is the carbon filter, and the third stage of filtration is PlasmaWave.

Besides, there is a pre-filter that removes large particles. All filters used in the C535 are not washable except pre-filter.


The air first goes through the Winix C535 pre-filter. This stage is the first line of defense against the most extensive airborne particles found indoors.

The pre-filter is washable and should be cleaned on average every 14 days. Pre-filter will protect other filters, extend their lives, and make the whole machine work better.

Carbon Filter

The carbon filter is not made up of carbon pellets. The carbon filter in the Winix C535 is a fibrous filter coated with carbon. Carbon filters reduce VOCs and household odors from cooking, pets, and smoke.

This type of carbon filtration is common in many air purifiers. For example, Coway Mighty uses a fibrous carbon filter. The Winix 5300-2 and Winix P300, which are also popular models from the Winix company, use an identical filter for gas filtration.

True HEPA filter

The true HEPA filter captures 99.97% of airborne particles, including pollen, mold spores, dust, pet dander, microbes, and smoke. Almost all the particles that are as small as 0.3 microns in size.

A true HEPA filter is not washable, and under no circumstances should it be washed or cleaned in any other way.


I don’t particularly appreciate that PlasmaWave turns on every time the device starts. I think it would be more practical to leave this option off and let users decide to use it. However, the PlasmaWave can be turned off at any time.

How does PlasmaWave technology work?

The PlasmaWave technology creates a low electrical discharge to produce dual polarity ions ( + hydrogen (H+) and – oxygen ions (-O2)) from air moisture. The ions connect themselves to air pollutants’ surface to form Hydroxyls by removing hydrogen from the air structure. This synergy eliminates air pollutants and allows the ions to use the absent Hydrogen ion, removed from the air pollutants’ structure to return as air moisture (H2O).

Does Winix C535 produce ozone?

Winix claims C535 does not produce harmful ozone. Plasmawave CARB certificate has strict California state rules, which then implies that Winix C535 is actually safe to use. C535 has an ozone emission rating below the 0.05 parts per million limit, far from dangerous levels.

Noise Test

The Winix C535 is truly not a very loud device. A small objection is a drastic difference in volume between 4th, and 3rd speed. I feel like one speed is missing in-between.

At the first speed, Winix produces a noise of 42.4 dBA. At the second speed, it makes a noise of 44.2 dBA; at the third speed, it creates a noise of 47.1 dBA, while at the fourth speed, i.e., in turbo mode, the Winix C535 produces 63.2 dBA.

I am extremely satisfied and delighted with the sleep mode, which, when turned on, produces a noise of about 40.8 dBA.

Thanks to the high-quality engine, there is no rattling or unpleasant sound at any speed.

Performance Tests

I tested the Winix C535 in various rooms and conditions.

When it comes to general performance, the biggest complaint I have is the auto mode, and only because the smart sensor only detects odors. The main reason is that this way, the Winix C535 is not predestined for every user. It is a widespread situation when there is more dust in the room than smoke or other odors.

On the other hand, the auto mode feature has made it much easier for me to use the Winix C535 model, mostly due to the automatic switch to sleep mode during the night.

320 sq. ft. Room Test 

I tested the Winix C535 in a room of 320 sq. ft. for 60 min.

The device has made enviable results. The Winix C535 has significantly improved air quality. I used it on Turbo Mode (4 fan speed) all the time.

Winix improved the air quality in the first 30 minutes, so the AQI dropped below 50, which is a sign that the air is of good quality.

320 sq. ft. Room Test – Auto Mode

I tested the Winix C535 in the same room, in identical conditions, but this time with the auto mode ion.

As I already mentioned in the review, the auto mode is not always the best solution because the smart sensor only detects odors. However, the device improved air quality by about 90% in 60 minutes.

The Winix C535 lowered the Air Quality Index from 86 to 9. My recommendation is to use auto mode if you plan to use the Winix C535 at night or if your environment is polluted by wild smoke, cooking odors, smog, or something like that.

Operating Costs

The Winix C535 uses a 70W motor. This device is much more potent than some other, smaller devices, which I have tested so far. Interestingly, the C535 consumes only about 6W at a first speed, which is in the range of much smaller and weaker devices. In sleep mode, the Winix C535 is an even smaller consumer; more precisely, it consumes only 3W.

If you leave the Winix C535, running 24h on turbo mode, your electricity bill will be increased by about $ 4.8. In addition to the electricity bill, there is also a filter replacement cost that is slightly higher for the Winix C535. A replacement filter costs about half as much as a Winix C535 product. Therefore, if we consider the replacement filter’s price and the annual electricity consumption in one year, the C535 air purifier’s maintenance will cost you almost as much as the C535 device itself.

Final Thoughts

Winix C535 is an air purifier that is not intended for small rooms. Primarily because of its size and its power. It is ideal for medium or large rooms.

On all the tests I did, I got great results. The only complaint I have on the Winix C535 air purifier is that they use a fibrous carbon filter instead of carbon pellets and that the smart sensor only detects odors.

Winix for C535 gives a two years warranty. The price-quality ratio is excellent, even if we consider a slightly more expensive filter replacement. Winix has done phenomenal results on all performance tests, volume tests, and other tests I did.

The C535 is a great option to buy if you want to get rid of: cooking odors, wildfire smell, or other gases. Also, if you want cleaner air during the night, with undisturbed sleep, I recommend the C535.

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