Yes. Although I only tend to use the heating element around this time of year. It’s great to take the chill out of the room and does build the temperate up. My advice, place it in the room either next to you or where the airflow will directly hit you when you put the heater one. If you want to maintain a temperate, use the heater in Auto and set oscillation.

Here’s two posts that might help you get started !

(1) Using Auto mode (Purifier, Heater and Humidify) | Dyson Community

(2) Keeping your purifier performing at its best | Dyson Community

Did you check the website caveats?

Dyson’s Purifier Hot + Cool Machines have built in thermostats which can save you up to 30% in running costs when maintaining room temperature.¹¹

¹¹.After reaching target temperature and maintaining it. Tested in a 35 m³ chamber when using the hot air mode and the product setting temperature is 25 °C. Comparing with continuous operation with power consumption of 2050W. Real life results may vary depending on room insulation.

May explain the leaflet text. 

I understand what is being said but I am still concerned that the safety document suggests occasional use.

Why would I want to have the heat pointing towards me if it was tested in a 35m3 chamber at 25'c.

I have the Dyson set to Auto and 20'c.

It performs well .... but based on the safety document comment on the front page .... is it ok to have it on Auto for 12 hours & more?

Hi @Actuator,

Congratulations on your new Dyson Purifier Hot+Cool Formaldehyde! Your machine is suitable for whole-room heating, with long range airflow projection to heat the room evenly. We recommend use in well-insulated rooms to help make sure your machine can reach and maintain the target temperature you've chosen.

It's safe to use continually. Auto mode, and the intelligent themostat, mean it can react to pollution events as they happen, and maintain temperature to the degree. It's ideal if you're just looking to heat the room you're currently in, without needlessly running your full central heating system.

Hope this helps, but we're here if there's anything else you wanted to know.

Yes. I interpret the text as: 

If the space you’re using it in isn’t well insulated, you may want to use it occasionally. Using it on full power to heat a space with air escaping will cost a fortune. It doesn’t necessarily mean that it can’t be used.