SereneLife - 7,000 BTU Portable Air Conditioner (SLPAC7UK)

I bought one for about £150 in Jan. Used it for about 6 days and I reckon it has paid for itself already. Might go look at current sale price actually.. EDIT: Exact same one is now £229. Edit 2: I got it from Amazon, it's a 7000BTU SereneLife portable air conditioner.

Some very good advice has been shared by u/loco2000; I'll just add that if you’re going the portable route, look for a model with a dual hose system. Believe me it’s worth the upgrade. Bit of physics: single hose units create negative pressure in the room which ends up pulling warm air back in from other parts of the apartment. That makes the unit work harder and cool less efficiently. Dual hose models avoid this problem and cool faster and more evenly. In terms of a specific unit, I’d recommend the serenelife portable AC. It covers up to 450 sq ft so it’ll easily handle your 300 sq ft bedroom. It’s got a built in dehumidifier and heating mode so it’ll be usable year round.