Essentially the Dyson Hot performs very similarly to a bog standard fan heater in terms of the amount of hot air it pumps out. However, the way the air is projected means it does heat a room much quicker and more evenly than other fan heaters we've tried.
Also, the air flow is - or, thanks to the temperature control, can be - pleasingly warm rather than hot even when closeup. This means that whoever's sat next to the fan doesn't get roasted while everyone else is still freezing. Equally, though, this does mean you don't quite get that quick hand-warming effect that a normal fan heater provides.
Our other main gripe is that the temperature control doesn't control the ambient room temperature but rather that of the air leaving the fan. So if you pick a nice ambient temperature of, say, 20 degree Celsius, instead of getting the room up to temperature and turning off for a while - giving the user some peace from the fan noise - the Hot simply steadily churns out rather tepid 20 degree air.
The above is particuarly an issue as the Dyson Hot isn't exactly quiet. It's not significantly worse than a normal fan heater but it's nonetheless the case that you wouldn't want to use this as a background heater. Instead we'd recommend a classic oil filled radiator for those situations.
On the cold (air) front, the Dyson Hot performs rather better, providing a powerful cooling stream of air that thanks to the automatic rotation can be shared across a whole room of people. As with the not-Hot Air Multipliers, though, there's no option to mount the Hot on a wall as you can with most normal desk fans.
All of which brings us to the inevitable downside of any Dyson product: price. Its 2-in-1 hot and cold functionality arguably suggests it offers greater value than the cold-only AM01, but with a £299 RRP it is £100 more expensive. We have seen the Hot available online for £250 (and the AM01 for £170), but it is still a sizeable outlay for something that, when all is said and done, probably won't get used that often (unlike a vacuum cleaner). We'd suggest the outlay would be best spent turning up your thermostat during winter months for a number of years.
In many ways the Hot is a typical Dyson product: smart, innovative and arguably stylish, but like most Dyson products it also costs rather more than much of the competition. Dyson arguably gets away with charging a premium with its vacuum cleaners (and its hand dryers we suppose) because they're something everyone needs anyway. But both cooling desk fans and fan heaters are hardly what many people would consider essential to everyday living.
Nonetheless, there is something compelling about the all-in-one approach of the Dyson Hot and if money isn't an issue it definitely gets the job done.