Aircon Price Guide Get quotes
Menu
Get quotes

Evaporative cooling or reverse cycle, by climate

The right answer depends less on the brochure than on the air outside your window. Start with your climate zone.

Figures checked

Short answer

Where summers are humid, choose reverse cycle. energy.gov.au says evaporative coolers become less effective as humidity rises↗, and they have no heating as standard↗. The building code's humid climate zones, 1 and 2, include Darwin, Cairns and Townsville↗ and Brisbane and coastal Queensland↗.

Two ways to cool a room: an evaporative cooler pulls outside air through wet pads and lets it flow out of the room, while a reverse cycle system recirculates room air and moves the heat to an outdoor unit Evaporative cooler outside air wet pads air out Reverse cycle room air recirculates heat moved outside
Evaporative coolers push outside air through the house. Reverse cycle works on the air already inside.

Which climate zone are you in?

The National Construction Code groups Australia into eight climate zones↗. This is how it describes each one:

ZoneDescribed asIncludes
1 high humidity summer, warm winter↗ Darwin, Cairns and Townsville↗
2 warm humid summer, mild winter↗ Brisbane and coastal Queensland↗
3 hot dry summer, warm winter↗ Look up your address
4 hot dry summer, cool winter↗ Look up your address
5 warm temperate↗ Look up your address
6 mild temperate↗ Look up your address
7 cool temperate↗ Look up your address
8 alpine↗ Look up your address

The ABCB climate map will search by address, suburb or postcode↗, which is quicker than guessing from a state map.

Why does humidity undo evaporative cooling?

An evaporative cooler cools air by evaporating water into it. Dry air soaks that water up readily. Air that already holds a lot of moisture does not, which is why energy.gov.au describes evaporative coolers as less effective as humidity rises↗.

Anyone who has spent a February afternoon in Cairns knows the feeling that description is warning about. A reverse cycle system does not add water to the room at all, so the humid north is where it earns its keep.

What about heating in winter?

Evaporative coolers have no heating as standard↗, so a home that needs winter warmth will need a second system. A reverse cycle air conditioner covers both, and when heating it moves 3 to 5 units of heat per unit of electricity↗. Our heating running cost guide explains why that matters.

Where is the choice less clear?

Zones 3 and 4 are described as hot dry summer, warm winter↗ and hot dry summer, cool winter↗. Dry summers are where evaporative cooling works with the climate rather than against it. The cool winter in zone 4 still points towards needing heat from somewhere.

If you live in either zone, ask installers of both types for a running cost estimate for your house, and compare those rather than the purchase price alone.