One of Dyson's key engineers has explained to TechRadar why even people with cosy centrally-heated houses will be buying the new fan heater from the company, and also why the dual-purpose device will not cannibalise sales of fans.

Tom Crawford is named alongside Sir James Dyson in the patent of the Dyson fan, and he was at the UK launch of the latest product from the company - the Dyson Hot.

The Dyson Hot is not just a fan heater but also a air multiplier fan, but Crawford is keen to point out that dual purpose doesn't necessarily mean that it makes sense to plump for it when you are looking to cool a room.

Dual-purpose

" It does have dual purpose but in fan mode it doesn't give as much multiplication in air flow as one of the existing fans, he told TechRadar. "It is dual purpose but as a fan it doesn't deliver as much.

"The heater provides 6 times airflow whereas the fan goes up to 18 times - which is quite a significant difference."

Dyson with a hot fan

TechRadar asked Crawford if the UK was a natural market for a premium fan-heater, with those that are considering forking out just shy of £270 likely to have double glazing and central heating.

"Heater sales are huge in Europe and people want them to heat a room quickly," explained Crawford.

"Central heating takes time to heat an entire house and, also you normally heat the entire house [when you turn it on] whereas a portable heater allows you to quickly heat individual rooms and also carry it with you when you move."

Years in the making

Finally, Crawford explained that, despite building on the now familiar air multiplier tech in Dyson fans, making it a heater as well was no mean feat.

"It's been three years in the making," he said. "We really had to go back to basics.

"We had to go back to the fan and work out how we could add in heating technology which was a lot harder than you could imagine."