What Makes a Good Air Purifier?

To answer this question well, the industry has been working hard for years. However, under the mainstream hardware form factor, air purifiers still have pain points such as "small coverage area," "loud operating noise," and "high consumable costs." In non-mainstream product forms, the problems are even more severe. For example, Xiao Lei once bought a coffee-table-shaped air purifier with a built-in HEPA filter. He originally hoped this air purifier could serve multiple purposes and save his limited apartment space. Still, its low working efficiency, hard-to-ignore operating noise, and purely manual operation mode—comparable to the AC of a 20-year-old car—made him decisively list it on Xianyu (a second-hand marketplace) after using it for half a year.

It is precisely for this reason that upon receiving the Dreame PB20 air purifier for review, LeiTech (ID: leitech) immediately brought it home to conduct a comprehensive air purification of Xiao Lei’s residence.

Image source: LeiTech

Because of this, after receiving the Dreame PB20 air purifier sent for testing, Lei Tech (ID: leitech) immediately transported it home to give the house a thorough air cleaning.

Purifying Multiple "Pollutants" at Once

For long-time rhinitis sufferers like Xiao Lei, more than half of the year is spent dealing with particulate matter: spring pollen, winter PM2.5, dust mite excrement kicked up during seasonal transitions, and dust accumulated after a day of open-window ventilation. Even if these don't get inhaled into the lungs, they can cause the nasal cavity and throat to swell for half a day.

How effective is the PB20 at purifying these particulates? Over the past week, without deliberately opening windows for ventilation, Xiao Lei directly cleaned the carpets at home near the purifier, changed to a thicker duvet, and pulled out all long-dusted clothes to wash them.

Faced with this sudden dust storm, the PB20 would quickly kick into a higher fan-speed purification mode. But in less than half an hour, the PB20 completed a full air purification cycle and dropped back to its default low-power standby mode.

It's worth mentioning that the PB20 can not only purify particulates like PM2.5 and PM10 but also purify formaldehyde indoors. Note that I said "purify," not simply "capture."

Image source: LeiTech

In the past, many so-called air purifiers used formaldehyde capture solutions. Put plainly, this means adsorbing formaldehyde from the air onto activated carbon. Obviously, this doesn't truly solve the formaldehyde problem at home. Moreover, as temperatures rise in summer, formaldehyde may be released again.

To solve this problem, air purifier brands have begun researching "decomposition" technical routes in recent years, using catalytic technology to break down formaldehyde into carbon dioxide and water. For example, the Dreame PB20 uses a manganese-based composite formaldehyde-capturing catalytic layer. According to Dreame, this catalytic layer can efficiently remove formaldehyde and avoid secondary release after absorption. Additionally, the PB20 supports ultraviolet sterilization.

Image source: LeiTech

Since there isn't much newly purchased furniture in Xiao Lei's apartment, formaldehyde levels have always been low. However, during the PB20 experience, Xiao Lei bought a new mattress. Even when opening that mattress, which was wrapped layer by layer in plastic bags, indoors, there was no obvious pungent odor. You could "smell" that the Dreame PB20's purification effect was indeed quite good.

High Airflow and Quiet Operation Can Coexist

Of course, there are many choices on the market if you want a purifier with high purification capacity. But if you also consider the purifier's quietness, the Dreame PB20 does quite well. Although the Dreame PB20 is indeed larger than any purifier Xiao Lei has used before, thanks to the larger volume, Dreame was able to fit two sets of fans inside the PB20.

Image source: LeiTech

Compared to the single-fan mode, which increases fan speed to boost airflow, a dual-fan architecture can effectively reduce the load on each fan. Even if the air intake during purification remains the same, the load on each fan inside the Dreame PB20 is only 1/2 that of a single-fan model. Lower load naturally means quieter operating noise. The Dreame PB20's noise level in sleep mode is only about 32-33 dB. Even if you place the PB20 directly in the bedroom, its operating sound is smaller than the circulation fan on Xiao Lei's bedside table turned to the lowest setting, so it won't affect sleep quality at all.

During daytime use, Xiao Lei also compared the PB20’s noise levels across different fan speeds against other household appliances. At Level 3, its noise approximates that of an air conditioner operating in gentle-breeze mode; at Level 4, it matches the noise level of the circulating fan in the living room. At Level 5 or above, the PB20 produces noticeably higher operational noise—but correspondingly delivers exceptional airflow volume and purification efficiency.

In other words, if your indoor air pollution is severe enough to warrant the PB20 running at full capacity, it will complete purification rapidly and revert to its relatively quiet default mode shortly thereafter. It’s worth noting that Xiao Lei resides in a large, open-plan apartment—even in spaces with high ceilings, the PB20 maintains strong cleaning efficiency.

In fact, according to Dreame, the PB20 can fully purify a 190-square-meter open-plan residence in just 17 minutes. For most households, therefore, a single Dreame PB20 is more than sufficient to meet whole-home air purification needs.

Moreover, for specialized purification requirements, the Dreame PB20 supports three distinct filter configurations: choose the formaldehyde-removal filter set for new homes to rapidly eliminate indoor formaldehyde; opt for the antibacterial deodorizing filter set or the all-in-one high-efficiency filter set for everyday use. With one filter set priced at RMB 899 and rated for a three-year lifespan, the PB20 represents a genuinely sound “health investment” over the long term.

Dreame's Design is as Exquisite as Ever

Actually, in terms of performance, Lei Tech believes that the Dreame PB20 has achieved the top level in the current industry in both purification efficiency and operating noise. Of course, the high performance of the PB20 corresponds to a higher price. Generally speaking, mid-range home air purifiers from domestic brands are priced around 2,000-3,000 yuan. But even during Double 11, the final price of the Dreame PB20 is 3,599 yuan (down from 4,976.38 yuan).

But let's not forget that the PB20 is obviously not aimed at ordinary small apartments. Because the PB20's dimensions are a size larger than conventional home air purifiers, we must consider placement issues at home when purchasing.

Image source: LeiTech

Take Xiao Lei’s case: for the past week, he simply placed the PB20 beside his sofa and used it as a side table. However, the PB20 features dual-side air intake—so placing it flush against a wall blocks one intake panel. Furthermore, to facilitate mobility, Dreame equips the PB20 with four smooth-rolling omnidirectional casters as base feet—making Xiao Lei hesitant to place fragile items atop it.

Although the PB20 is larger than typical air purifiers, its overall aesthetic remains minimalist and restrained, with clean, sharp lines that effortlessly blend into diverse interior styles. Its parallel-line front panel and concealed indicator lights also harmonize well with a Nordic-brand PC chassis Xiao Lei previously owned. In terms of visual appeal, the Dreame PB20 is virtually flawless.

Image source: LeiTech

On the smart connectivity front, the Dreame PB20 seamlessly integrates into Dreame’s whole-home smart app. Users can monitor real-time operational status, purification efficiency, and remaining filter life directly within the app.

A Super Practical Air Purifier for Large Apartments

As usual, before giving purchasing advice, we first summarize the pros and cons of the Dreame PB20 according to Lei Tech's review template:

Strengths:

1. Outstanding particulate matter purification—real-world testing shows it returns to standby mode within 30 minutes after heavy dust generation;
2. Formaldehyde decomposition capability and UV sterilization;
3. Dual-fan design delivers extremely high airflow—suitable even for large open-plan residences;
4. Modular filter assembly allows individual replacement, delivering superior long-term cost-effectiveness.

Weaknesses:

1. Relatively large physical footprint, demanding dedicated placement space;
2. Dual-side filter configuration restricts placement options;
3. Touch panel surface is prone to fingerprints and scratches.

So who is the Dreame PB20 best suited for? If you live in a large open-plan residence or an open-concept living-dining area with genuine air purification needs—and are tired of the classic dilemma where “maximum fan speed is too noisy while minimum speed is insufficient”—then the PB20’s dual-fan architecture genuinely resolves this pain point. This is especially true for households with allergic rhinitis patients, individuals with heightened sensitivity, or families who’ve recently added new furniture or mattresses and require extended, continuous purification. In these scenarios, the PB20’s purification efficiency and silent operation truly justify its price.

Conversely, if you reside in a small apartment or studio where regular window ventilation adequately addresses most air-quality concerns, the PB20’s capabilities would be overkill. Compared to the large-space-focused PB20, Dreame’s smaller-form-factor models would likely better suit your needs.

Image source: LeiTech

Beyond evaluating this single product, LeiTech believes the emergence of the Dreame PB20 signifies a broader industry shift—from competing on spec sheets toward innovating in structural design, and from brute-force “spec stacking” to solving specific real-world user scenarios. Historically, air purifiers competed primarily on CADR ratings and filter-layer counts—often at the expense of user experience. By contrast, Dreame’s dual-fan architecture strikes an elegant balance between airflow volume and noise control. In LeiTech’s view, this user-centric design philosophy makes the PB20 far more approachable and practical.

Ultimately, an air purifier—like a refrigerator or water purifier—is an appliance you “turn on and leave on.” If users must “endure” using an air purifier, then the product has fundamentally failed—and will inevitably be phased out by the market. Yet if you’re looking to equip your new home with a robust, high-performance air purifier during the Singles’ Day sale, the Dreame PB20 is certainly worth serious consideration.