Dyson Pure Hot+Cool Review

Introduction:

Dyson currently has several variations of air purifying fans on sale and the one that is being reviewed here is the most expensive out of the bunch called the Dyson Pure Hot+Cool purifying fan.

Dyson currently offers the ‘Dyson Pure Cool desk’ for £399.99 the ‘Dyson Pure Cool tower’ for £499.99, the ‘Dyson Pure Hot+Cool Link’ for £499.99 and the ‘Dyson Pure Hot+Cool’ for £549.99. The units can also be found on both ​John Lewis and Curry's websites for the same price.

The latest model in Dyson’s line of air-purifying fans is the ‘Dyson Pure Hot+Cool’ air purifier. It has been advertised as being able to offer both particulate and gas filtration. According to Dyson, the unit uses a proper HEPA filter to eliminate particulate pollution and a carbon filter to deal with gases, chemicals and odours. The unit is able to display air quality readings on the device and also via the ‘Dyson Link’ app. The unit claims to record the quality of the air in relation to PM2.5, PM10, Nitrogen Dioxide (NO2), Volatile Organic Compounds (VOCs), as well as temperature and humidity levels.

The ‘Dyson pure Hot+Cool’ features 10 different fan speed settings. It can be controlled via the remote (included as standard) or via the ‘Dyson Link’ app on supported smartphones. A timer function allows you to specify when the unit turns on/off and on what speed setting.

Marketing of the Dyson Pure Hot+Cool

The ‘Dyson Pure Hot+Cool’ is marketed as a ‘purifier fan heater’[1], meaning it is supposed to be able to purify the air, be used as a heater or a fan. Dyson says that “you could use three products, for three jobs…or just one machine”[2].

They claim that the Dyson Pure Hot+Cool “senses particles and gases, then reports them in real-time”[3].  These results can be viewed directly on the unit or on the ‘Dyson Link’ app.

Dyson also claim that they use a ‘Glass HEPA’ filter and that the filter system is able to “capture 99.95% of microscopic allergens and pollutants as small as 0.1 microns”[4]. In terms of the airflow that the unit can produce, Dyson says that it projects over ‘290l/s’ on the highest speed setting; which is equivalent to 1044 m3/h.

Dyson Pure Hot+Cool Review- First impressions

The styling of the product is the same as other Dyson fans, heaters and purifying fans. The construction of the unit is made largely from plastic. The plastic that has been used for the ‘Air Multiplier loop’ has a glossy white finish and during our trial – seemed to become static and attract dust easily. Cleaning the loop is most likely going to be a regular occurrence.

The remote of the Dyson Pure Hot+Cool is similar in design and functionality to other Dyson fans and purifying fan remotes, with it being slightly curved and magnetic which enables it to attach to the top of the fan purifier for storage.

Dyson Pure Hot+Cool Review- a Closer look

On the previous Dyson units, the ‘air multiplier loop’ was separate from the main base where the fan and motor were located and would need to be connected prior to use, but this is not the case with this model as the loop is already attached to the base.

Gaining access to the filter compartment is easy; you just push down on the two buttons located on either side of the filter housing and both parts come off. By default the carbon filter is not pre-installed within the unit, but arrives sealed in separate bags and will need to be fitted prior to use, this is done to protect the carbon from prematurely saturating, i.e. stay fresh until you actually start using the unit. Dyson has placed a large sticker on the bottom of the filter casing to remind you that you need to unwrap and insert the carbon filters prior to use.

The ‘Dyson Pure Hot+Cool’ purifying fan incorporates a heating element into the design.

Dyson Pure Hot+Cool Review - App

As we have seen in previous Dyson models, the ‘Dyson Pure Hot+Cool’ is Wi-Fi enabled; meaning that this purifying fan can be controlled on your smartphone. Another feature of the ‘Dyson Pure Hot+Cool’ purifying fan is that it can be controlled from a compatible smartphone via the ‘Dyson Link’ app. From within the app, you have all the controls that are available with the Dyson remote control, with a few other added features and functions. You are, for example, able to view the air quality data that the Dyson is reporting in a graph format. This gives you a visual representation of what the unit thinks the air quality is like in your environment. Within the app, it supposedly shows readings for PM2.5, PM10, VOCs, NO2, temperature and humidity. The Dyson Link app is also able to report what the outdoor air quality is like for the city you are in. The outdoor readings are based on the Air Quality Index (AQI) which is a scale from 1 – 10, 1 being the lowest level of pollution and 10 being the highest. The data is taken from the ‘Department for Environment, Food and Rural Affairs’ (DEFRA) website[5].

In terms of the extra functions of the app, you are able to programme the unit to turn on when you want it to. You can specify individual timers for each day of the week so if you do not have a set schedule this is a great feature to have available.

You can also control your Dyson unit by using your voice, provided you have an existing voice service, such as Amazon ‘Alexa’.

Dyson Pure Hot+Cool Review - Filtration

When it comes to what features are important when choosing an air purifier, one of the most important things to consider is the filtration efficiency of the unit. The ‘Dyson Pure Hot+Cool’ is advertised as having a Glass HEPA filter which Dyson claims to be 9 meters of ‘Borosilicate microfibers’ and pleated over 200 times. Dyson also say that the filter can “remove 99.95% of allergens and pollutants as small as 0.1 microns”[6].

With the filtration efficiency in mind, we put the unit to the test and found that the actual filtration efficiency of the HEPA filter and how it is fit in the unit is very good. However, there is a big problem. Just as with the previous model, the ‘Air Multiplier Effect’ is such that only a very small amount of air that the unit moves is actually filtered. Thus, the overall filtration efficiency for the whole system is very poor. In air purification you want the highest level of filtration efficiency in combination with high airflow to make a significant reduction in contamination levels. The Dyson Pure Hot+Cool has a high airflow, however, the whole system filtration efficiency (i.e. the level of filtration of the air it actually moves) is low. More on this under the ‘Airflow’ section.

The Dyson Pure Hot+Cool air purifier also contains activated carbon which is used to remove gases, chemicals and odours from the air. Apparently, the activated carbon is “engineered using a dense layer of carbon crystals” which has been “treated with oxygen to make it more porous.” Dyson says this “increases the carbon’s surface area, further helping to trap gases – such as formaldehyde, benzene and NO2”[7]. All of this just sounds wonderful.

Dyson, however, also say that the weight of carbon used in their carbon filter is 300 grams[8]. The entire weight of the filter, including the housing, weighs about 500 grams, so 300 grams for the carbon sounds about right. However, 300 grams of carbon is not very much, especially for an air purifier at this price point, and certainly, one that claims to use ‘advanced purification’[9]. It is much more carbon than the amount that was used in the Dyson Pure cool unit that was released previously. At least this time around, Dyson has gone for a completely separate carbon filter.

Nevertheless, we would have liked to have seen more carbon in the filter to provide effective long term gas and chemical removal in line with the claimed filter life.

Dyson currently sells the replacement HEPA and the Carbon filters for £50 each and this can be found on the Dyson website. Dyson has said that the filters should last about 12 months if you operate the unit for 12 hours a day but they don’t tell you what speed setting that is based on and what the pollution they expect. With 10 different speed settings available, the actual filter life could be significantly shorter or longer.

Airflow

Airflow is another important factor to take into consideration when looking at a potential air purifier. You need to ensure that the air purifier is able to purify enough air for the given space that it is to be used in. Ideally, you would want the volume of air to be cleaned about 2 – 3 times per hour in order to be effective. When it comes to the Dyson Pure Hot+Cool, Dyson claim that the unit has an airflow rate of 290 litres per second. 290l/s converts to 1044 m3/h, which is a considerably high airflow rate for such as a small air purifier.

As Sir James Dyson himself has stated when explaining how the air multiplier technology works, only a small percentage of air gets pulled in through the bottom of the unit. The air then gets multiplied by their ‘Air Multiplier Technology’ by about 16 times. Now, this is just great for a regular fan but it is a problem for an air purifier because this means that of the total airflow, the air that is purified is actually only a fraction of the air the unit moves. On the highest speed setting only 65m3/h is cleaned as this is the amount that passes through the filter at the bottom of the Dyson Pure Hot+Cool. And you would only get 65m3/h of purified air on the highest speed setting. Due to the low level of actual air being filtered, it is hard to believe the Dyson Pure Hot+Cool is able to produce a meaningful reduction in contamination levels in any given room.

Our suspicion is obviously that the Dyson Pure Hot+Cool is not really a purpose-built air purifier and that adding the filter (i.e. making air purifying fan out of the fan) was a bit of an afterthought.  The design of the Dyson Pure Hot+Cool is likely to have started out as a purpose-built fan, and in that regard, it works very well. Later on, Dyson might have decided to add a couple of filters and call it a ‘purifying fan’ but the performance is not good for an air purifier.

It is interesting to also see how the Multiplier as a key feature of the Dyson fans has changed.  Originally, we saw the Multiplier effect being described as a feature that creates a vacuum because of the way the air comes out of the back of the units loop and is pushed over the loop itself. Similar to the air that passes the wing of an airplane.  The Dyson Pure Hot+Cool, however, seems to have the air outlet on the front rather than the back of the loop – i.e. it does not use what Dyson originally described as the ‘Mulitplier effect’.

The airflow of the Dyson Pure Hot+Cool is still very high and the fan does not seem to have changed much. But why was the air outlet moved? Our suspicion is that the original design was a bit too noisy and that this improved the overall sound levels of the Dyson Pure Hot+Cool.

Dyson Pure Hot+Cool Review Summary

The Dyson Pure Hot+Cool is marketed as a three in one product; a fan, a heater and a purifying fan. The main drawback of the Dyson Pure Hot+Cool is the fact that the purifying aspect is not as good as it should be considering the price tag of the product. Granted, Dyson mostly calls the unit an air-purifying fan rather than an air purifier, nevertheless, it is a lot of fan and little purifier. If you spend £549.99 for an air purifier, you should expect to get more than 65 m3/h in clean air per hour.  You might also not always appreciate the large air movement that comes with the 65 m3/h of clean air.

While the Dyson does contain carbon, this only equates to 300g which is not much. This small amount of carbon would, while being able to remove small amounts of gases and chemicals, not be suitable for dealing with elevated gas and chemical levels or effectively take out gases over a longer period of time.

Dyson has a somewhat misleading statement on their site where they claim “the machine projects over 290 litres of smooth, purifier air per second”[10] which might make you think that all 290 litres of air is purified – well they are not.

Another concern we have is in regards to the life of the filter and its filtration efficiency. It remains to be seen whether the Dyson Pure Hot+Cool can maintain its filtration efficiency when the filter gets loaded as this is usually the case with a lot of air purifiers on the market. Also, filter changes could be more frequent due to Dyson not specifying what speed setting the filter life calculator is based on, this would also increase the maintenance cost of the unit.

As you would expect with a Dyson product, the fan element works well, with a steady stream of air being delivered at you directly or via the different oscillation modes. It should be noted that the Dyson works like a regular fan, in so far that you need to be in the path of the directed air to benefit from the cooling effect.

In terms of the heating capabilities, we found this worked well too, with a good amount of heat being produced. The oscillation modes really helped here in heating the room evenly.

Overall, the Dyson is a good product but the price is steep considering especially when it is being sold as cleaning your air. If you are looking for an air purifier; whether that be for removing dust, pollen, viruses, bacteria or even to help with serious respiratory conditions we would recommend a standalone air purifier with proper HEPA filtration- that moves a lot of air and all the air is cleaned. If your main concern is the removal of gases and chemicals, then an air purifier with a larger quantity of high-quality carbon would give you best performance.  Some domestic units offer 2.5 kg or even 5.4 kg of high-quality carbon, rather than just 0.3 kg as in the Dyson Pure Hot+Cool.

[1]

1. www.dyson.co.uk/fans-and-heaters/dyson-fans-range.html

[2] [3] [4] www.dyson.co.uk/purifiers/dyson-pure-hot-cool-all-features.html

[5]
https://uk-air.defra.gov.uk/forecasting/

[6] [7] www.dyson.co.uk/purifiers/dyson-pure-hot-cool-technology.html

[8] www.dyson.co.uk/purifiers/dyson-pure-hot-cool-engineering-story.html

[9] [10] www.dyson.co.uk/purifiers/dyson-pure-hot-cool-technology.html