Dyson Pure Cool Review: Tests Show Only 49% Effective

New Dyson Pure Cool TP04 tests show the purifier reduced indoor PM2.5 pollution levels by just 49% in a typical size room. This data adds to a growing amount of reviews and tests showing the Dyson air purifier underperforms purifiers far cheaper than it.

Dyson Pure Cool TP04 Test: Marketing Hype or Really Effective?

The Dyson Pure Cool TP04 air purifier is one the most-advertised air purifiers on the market. Dyson markets it as being “the only air purifier with 360° oscillation and air multiplier technology.” These are fancy sounding terms. But do they equate to more clean air and better protection for our health? To find out, Smart Air’s India team ran Dyson Pure Cool tests to see how well it performed in a real room – not a test lab.

The Test: Dyson Pure Cool Air Purifier

To measure the performance of the Dyson TP04 air purifier, Smart Air’s India team tested the Dyson purifier in the center of the 500 sq ft (46 sq m) office in New Delhi. Here’s the room, and the Dyson TP04 ready for testing:

Put to the test: Dyson TP04 versus the Sqair

Dyson’s Amazon page claims the TP04 is good for room sizes up to 600 sq ft. So for this test, we chose a room size of 500 sq ft.

Dyson TP04 room size area

To measure the performance, we ran overnight tests, turning the Dyson air purifier on every night from 10pm until 6am. That’s a total time of 10 hours, every night.

We then analyzed how much PM2.5 the Dyson TP04 cleaned during the tests by comparing the PM2.5 levels before turning on the purifier with the average level during the final four hours.

Since changes in outdoor air pollution levels during the tests can influence how well the Dyson TP04 performs, we repeated the tests over the course of many days. In total, we performed the tests 9 times over 9 days. 

Learn more: What is the Smart Air ‘room test’ and how we measure PM2.5 »

Results: Dyson TP04 Lowered Pollution Just 49%

Over 9 tests, the Dyson Pure Cool TP04 reduced PM2.5 levels by an average of just 49%.

Below is a breakdown for how the Dyson TP04 performed on each day of our 9 tests. The purifier filtered out less than 50% of PM2.5 on 6 of 9 days.

Disregarding days where the outdoor air pollution increased considerably during the test, the Dyson TP04 performed a little better, removing 62% of PM2.5 particles from the air. Here’s the data for one of those days:

Dyson Pure Cool TP04 Performance Test

Although slightly better than the 49% average across all 9 days, a 62% reduction after 8-hours is far from ideal. Air quality levels on this particular day still hovered around 25 micrograms, or 2.5 times above the WHO annual limit.

Other Third-Party Dyson Air Purifier Tests and Reviews

This is not the first time a Dyson air purifier has underperformed. Recently, the non-profit Consumer Reports tested Dyson’s TP04 model and found it under-performed many other air purifiers. Here is some of what Consumer Reports had to say:

Consumer Reports on Dyson Pure Cool TP04

Similarly, researchers at the University of Toronto tested the Dyson Pure Hot+Cool against several air purifiers and found a simple homemade purifier removed more particulate than the Dyson. 

Dyson TP04

Now, it’s possible that the Dyson isn’t designed for places like India. In India, PM2.5 levels average almost 9 times the WHO limit, and air pollution caused an estimated 120,000 deaths in 2020 alone. Perhaps it’s designed for countries with lower pollution levels like these? However the Dyson is heavily marketed in India, and a top seller on Amazon. This data shows that many of these buyers could well be under a false sense of security on just how clean the Dyson is making their air.

Dyson TP04 Review

The Dyson Pure Cool TP04 reduced PM2.5 pollution by an average of only 49% over 9 days of tests in India. The cleanest the Dyson made the air was still 2.5 times above the WHO safe limit, making it potentially an unsafe choice for use in India.

Smart Air

Open Data- Dyson TP04 Test Data

As part of Smart Air’s open-data pledge, the test data and results can be found here: Dyson TP04 air purifier – India test data

About Smart Air

The air purifier industry is opaque. It’s profit-driven, not health-driven. Big companies charge hundreds or thousands of dollars for technology that was invented over 70 years ago. We created Smart Air to bring open data and simple, effective air purifiers to opaque industry. We provide no-nonsense, honest purifiers to people (like us) who just want to breathe safe air.

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Smart Air is a social enterprise that creates simple, no-nonsense air purifiers and provides free education to protect people’s health from the effects of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.