Dyson Air Purifiers

Note: all Dyson air purifiers except for the Pure Cool Me share approximately the same design. Thus, our guide for Dyson air purifiers below applies to all models (except again, for the Pure Cool Me).

Advantages of Dyson Air Purifiers

1. They provide terrific airflow

a. substantial directional air flow over a large area

Dyson air purifiers feature “air multiplier technology” which is the same technology used in their fans.

It essentially involves forcing a lot of air through a small opening or slot around the inner rim of the ring that sits above the base of the unit.

There's still an impeller (fan) pulling air in and through the base of the unit just like every other air purifier, but once the air goes past impeller it goes through a small opening or slot around the inner rim of the ring above the unit.

Pushing air over a large surface area (throughout the inner rim) with a special design (small slot, specially curved rim, etc.) essentially multiplies air SPEED as it exits out of the air purifier.

Measured air speed for the Dyson we tested for review (the Pure Cool Link Desk) was actually quite low compared to most other air purifiers we’ve tested. The Dyson’s maximum outlet air speed was measured at about 12 ft/s. We tested multiple units with a maximum outlet air speed over 30 ft/s (the Coway AP-1512HH and Austin HealthMate, for example).

The difference is that that Dyson offers directional airflow. Air exits the Dyson in a forward direction while air exits most other units on the market in the upwards direction which doesn’t allow the user to choose the direction of that airflow.

The Dyson also provides this airflow over a large surface area. Remember, air exits the Dyson over the whole inner rim of a large ring perched on top of the unit. Air exits most other air purifiers through a single usually rectangular outlet.

Thus, substantial directional air flow over a large surface area is a unique feature of Dyson air purifiers. Do note, however, that this has little to no impact on air purification.

Air is a gas an immediately moves from areas of high particle concentration to low particle concentration. As soon as clean air exits the Dyson, unclean air that’s higher in particle concentration immediately swoops in and diffuses into that block of air.

The air in any particular room is constantly and very quickly moving towards total particle concentration equilibrium in the whole room. This is the dominant process that occurs in a room containing an active air purifier. The speed and direction of the newly cleaned air has very little impact on this process. What we just outlined is also the reason why there’s no such thing as a “clean air bubble” around an active air purifier. In practice, an air purifier lowers the particle concentration of the whole room. There is no such thing as a clean air bubble close to the air purifier.

b. oscillation

All Dyson air purifiers can be set to automatically oscillate back and forth in the x-axis. That is to say, they can be set to oscillate left to right.

Most other air purifiers on the market do not offer this functionality as they are primarily air purifiers (not multipurpose appliances that double as fans like these Dysons) and as we noted above, air direction (in this case constantly changing direction) has little to no impact on air purification.

c. tilt

Dyson air purifiers can physically be pushed to tilt air flow out of the unit up or down. Again, this is a unique feature to Dyson air purifiers.

2. Can be used as multipurpose appliances

a. regular airflow (operating these units on their standard air cleaning modes) provides a cooling effect giving these units the ability to double as fans.

Do note that the cooling models – Pure Cool Me, Pure Cool Desk, Pure Cool Tower – are not air conditioners. The cooling effect is solely provided by the airflow out of the unit (working like a fan).

b. the Pure Hot + Cool can also heat the air it processes

Most other air purifiers on the market do not offer this multipurpose functionality. They only clean the air. They cannot cool or heat it.

3. Smart functionality

All Dyson units provide

• App support – this allows you to monitor and control the unit with an app on your phone
• Voice control as well

There are several air purifiers on the market that do offer this functionality. However, it is especially well implemented in Dyson units. It’s clear from Dyson’s marketing that it’s a priority for them to synonymize their brand with the idea that their appliances are made with an emphasis on cutting edge technology. Thus, smart functionality is a priority for them. And it shows when you use their app to control their appliances. The user interface is well laid out, everything works, and everything works really well.

4. Easy control and fine tuning

a. easy control

Full app control via wifi.

A remote control with lots of buttons. Most other air purifiers on the market either do not have a remote control or if they do, have a very limited remote control – with few buttons. You can control absolutely everything there is to control – fan speed, auto modes, etc. - with the remote control included with a Dyson air purifier. The remote control for these units also snaps to top of unit (magnetically) for easy storage.

b. fine tuning

As many as 10 fan speeds. Most other air purifiers feature 3 or 4 fan speeds at most. We certainly appreciate the extra control this provides; however, the truth is that in practice, you’re likely to use only 2 or 3 fan speeds at most – one for when you want the unit to operate as quietly as possible (a low fan speed) and one for when you want the unit to clean the air as quickly as possible (the highest fan speed).

Auto mode, Night mode. These are not unique features but nice to have nonetheless. We generally do not recommend running any air purifier on auto mode. The air quality sensor installed on most air purifiers does not offer the necessary accuracy or precision to properly control the cleaning level (i.e. fan speed) for regular everyday use. We therefore recommend that you run the unit on a consistent manual fan speed if you can. For more information on this topic see here.

The night mode works relatively well – it essentially shuts off the LED display. However, it is itself an automatic mode. And again, we do not recommend running the unit on any auto mode but rather that you set fan speed manually.

5. The look of these units

There’s no denying that Dyson air purifiers have a very clean modern aesthetic. They really are great looking appliances.

Disadvantages of Dyson air purifiers

1. Low air processing power

Earlier we talked about the great airflow – directional airflow over a large area, oscillation, tilt – provided by Dyson air purifiers. However, none of these things affect the air purification process.

Ultimately, you’re buying an air purifier to lower the particle concentration in a particular room as quickly as possible.

The rate at which the overall particle concentration in a room is lowered is directly proportional to the rate at which an air purifier can take unclean air, processes it through a filter, and output clean air.

The rate at which an air purifier can do this is determined by the quality of the filters and the total VOLUME of air the air purifier can process each minute. This air processing rate is the air purifier’s CFM – the cubic feet (VOLUME) of air the air purifier can process every minute.

Air processing rate (CFM) is essentially unaffected by

• High airflow and
• High outlet air speed

Dyson air purifiers intake air at a low SPEED and then outputs air at a higher SPEED with “air multiplier technology”. Earlier we said that this output speed isn’t very high compared to most other air purifiers on the market but it’s still a much higher speed than the intake speed. Regardless, the air outlet speed has little to no effect on air processing rate or air purification. Earlier we discussed how airflow also does not affect air processing rate or air purification.

Again, two things impact air processing rate the most

• the quality of the air filters and the
• VOLUME of air pulled in and through the air purifier (CFM)

In terms of filters, Dyson units do just fine. They’re equipped with a combination HEPA/carbon filter. HEPA is the industry gold standard for particle filtration and carbon is the standard for gas filtration.

Here’s the problem: in terms of VOLUME (CFM), Dyson units do quite poorly.

All Dyson units currently on the market – and that includes even the largest of them all,–the Pure Cool Tower, have an effective output right around or below 100 CFM.

100 CFM is a very low output. For comparison, a relatively small standard air purifier like the GermGuardian AC4825 has an output of around 130 to 140 CFM.

What does all of this mean in practice? What this means is that Dyson air purifiers cannot be used in rooms much larger than 100 to 150 sq. ft. Anything larger than that and a Dyson air purifier will not be able to effectively lower particle concentration in the room.

And keep in mind that in such a room – a small room under 150 sq. ft. - they need to be run on maximum fan speed to be effective. For the Dyson Pure Cool Link Desk that’s fan speed 10 with a noise output of approx. 63 dB and a power draw of approx. 33 watts. For comparison, the top rated Winix 5500-2 outputs at slightly more than 100 CFM on a medium setting (it outputs at 250 CFM on its highest fan speed) where it makes less than 50 dB of noise and draws less than 10 watts of power.

If you were to run a Dyson air purifier on a lower setting than max – let’s say, fan speed 7 or 5 – it would not be able to lower particle concentration effectively in even a small 100 sq. ft. room. What do we mean by “effectively”? It would not be able to lower particle concentration in the room fast enough to maintain a particle concentration less than what you could accomplish with an HVAC system equipped with a good filter. And if you’re going through all the trouble of buying an air purifier to begin with, you certainly want your air purifier to perform better than your HVAC system in cleaning the air in your home.

2. Poor value

The least expensive Dyson air purifiers retail in the $300 to $400 range. Better equipped units like the Pure Hot + Cool cost upwards of $600 (approx.) or more.

What does all of that buy you? The effective air purification of a standard air purifier in the $80 to $100 range. Recall the GermGuardian AC4825 we referenced earlier. The AC4825 also has a HEPA and carbon filter and it offers even more output than any Dyson. The best part? It retails for about $80 – a fraction of the price for even the cheapest Dyson air purifier.

Replacement filters for standard air purifiers in this price range are also cheaper. They usually cost well under $50. Dyson air purifier replacement filters cost at least $70 or so.

The bottom line: if you’re strictly looking for an air purifier (and not an appliance that also heats and/or cools) – Dyson air purifiers are simply not a good value at all.

Recommendation

So what is our recommendation regarding Dyson air purifiers? It’s this:

Look into purchasing a Dyson air purifier if you value its

• Aesthetics
• Its airflow – you want to use it as a fan
• Its technology – you want to use the app, the very high quality remote control

If you don’t care for these things or if you don’t think they’re worth the Dyson’s much larger price tag, we recommend a standard run-of-the-mill air purifier.

Specifically, we recommend a top rated 250 CFM unit like the Coway Mighty or Winix 5500-2.

Top rated 250 CFM units have more than double the processing power of Dyson units. This means that they can be used in rooms twice as large – up to 300 sq. ft. on high fan speed – but also can be used in smaller rooms at lower fan speeds – where they’re much quieter than Dyson units that have to run on a maximum fan speed to be effective in a smaller room.

Top rated 250 CFM units are also more energy efficient and of course a much better value – they retail for around $150 to $200 with 250 CFM of output, still with a HEPA filter, and with an even better carbon filter for gas filtration than any Dyson unit currently on the market.