Zero Breeze Mark 2 Air Conditioner

Most cheap portable coolers are evaporative: they blow air across a wet pad, which cools by evaporating water. That works in dry heat and does nothing in humidity, which is exactly when you want it. The Mark 2 has a real refrigeration compressor, the same principle as the air conditioner in your house or your car. It pulls heat and moisture out of the air instead of adding moisture to it, so it works on a sticky night up north as well as a dry one inland.

Two thousand three hundred BTU is a personal-space number, and Zero Breeze are straight about it: 2.3 to 3.7 square metres. That's a two-person tent, a swag, a rooftop tent or the sleeping end of a van. In that space it makes a genuine difference on a 35 degree night. What it will not do is cool a caravan with the door open, a shed or a room in your house. Close the space up, insulate what you can, and it holds a comfortable temperature all night. Leave it open and you're cooling the outdoors.

A single-hose air conditioner blows the hot exhaust outside but takes its cooling air from the room, which pulls hot outside air back in through every gap. A dual-hose unit takes its air from outside and puts it back outside, so the sealed loop stays sealed and your cool air stays cool. The hoses adjust from 30 to 120cm, which gives you room to work out where the unit sits and where the heat exits. Getting both hoses properly outside is the single biggest thing you can do to make it perform.

On full it draws 240W. In Sleep mode it's 120W. On a 1,000Wh power station that's roughly four hours flat out or eight hours asleep; on a 2,000Wh unit you're looking at a full night on Sleep. That's the calculation to do before you buy, because an air conditioner that flattens your battery at 1am has solved nothing. Zero Breeze make a matching Mark 2 Smart Battery if you want a purpose-built pack rather than a general power station.

The Mark 2 is the smaller, cheaper and lighter one, at 2,300 BTU for a tent or a swag. The Mark 3 more than doubles the cooling at 5,280 BTU, adds heating and a full thermostat, and suits a van, a rooftop setup or a small cabin. It also costs more and draws more. If your space is genuinely small and your budget matters, the Mark 2 is the sensible pick. If you're cooling a van you sleep in every night, go up. Ring the store on 03 7056 6732 and we'll work it out with you.