A fan and a portable air conditioner solve different problems, and the confusion between them is common enough that it’s worth stating plainly: only one of them changes the room’s temperature.
What a fan actually does
A fan like the DREO DR-HPF002 moves air — 1,615 m (5299 ft)³/h by DREO’s own figure — across your skin, which speeds evaporation of sweat and feels cooling. The room’s air temperature doesn’t change.
What a portable air conditioner does
A compressor-based unit like the Dreo AC318S actively removes heat from the room’s air, genuinely lowering the temperature. That’s a fundamentally different mechanism, and it’s why an air conditioner works in conditions where a fan stops helping.
The honest dividing line
If the room is merely warm and still, a fan is cheaper to buy and run, and often enough. Once a room is genuinely hot — regularly above the mid-to-high 20s °C — a fan increasingly just moves hot air around, and a compressor becomes the tool that actually fixes the problem.
Running cost is not close
A fan draws tens of watts; a portable AC draws over a thousand. If the room only needs help occasionally, a fan run more often and an AC run only on the worst days is usually cheaper than either extreme.
What we would not do
Buy a portable air conditioner for a room that a fan and an open window handle fine most of the year. The upfront and running cost only pays off once the room’s heat genuinely exceeds what moving air can address.
The questions that keep coming up
Can a fan replace an air conditioner in a heatwave?
No. A fan moves air across skin, which feels cooling, but it does not lower the room's actual temperature the way a compressor does. In sustained high heat, a fan alone has real limits.
Last reviewed 24 August 2026