Evaporative Cooling vs Reverse Cycle: Which Suits You?

If you only read one line

Where summers are humid, choose reverse cycle. energy.gov.au says evaporative coolers are less effective on humid days^src, and it has evaporative cooling listed only as a cooling choice^src. The building code's humid climate zones are zone 1, northern Australia from Exmouth to south of Townsville^src, and zone 2, coastal Queensland from north of Mackay to just south of Coffs Harbour^src.

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^src. This is how it describes each one:

Zone	Described as	Includes
1	high humidity summer, warm winter^src	northern Australia from Exmouth to south of Townsville^src
2	warm humid summer, mild winter^src	coastal Queensland from north of Mackay to just south of Coffs Harbour^src
3	hot dry summer, warm winter^src	Look up your address
4	hot dry summer, cool winter^src	Look up your address
5	warm temperate^src	Look up your address
6	mild temperate^src	Look up your address
7	cool temperate^src	Look up your address
8	alpine^src	Look up your address

On the ABCB climate map you can search by address or postcode^src, 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 says evaporative coolers work well in low-humidity inland regions and are less effective on humid days^src.

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 in the humid north it keeps working when an evaporative cooler would struggle.

What about heating in winter?

Evaporative cooling is listed only as a cooling choice^src on energy.gov.au, 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^src. Our heating running cost guide explains why that matters.

The evaporative cooler has no bar: energy.gov.au lists it as a cooling choice, not a heating one. Source: energy.gov.au; Energy Rating, Australian Government.

Show the numbers

Winter heat from each system, per unit of electricity
Evaporative cooler	listed only as a cooling choice
Reverse cycle air conditioner	3 to 5 units

Where is the choice less clear?

Zones 3 and 4 are described as hot dry summer, warm winter^src and hot dry summer, cool winter^src. 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.

Where these figures come from

ABCB Climate Map, Australian Building Codes Board: The National Construction Code has eight climate zones, and the zones on the ABCB climate map were created using Bureau of Meteorology climatic data. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 1 is described as high humidity summer, warm winter. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 2 is described as warm humid summer, mild winter. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 3 is described as hot dry summer, warm winter. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 4 is described as hot dry summer, cool winter. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 5 is described as warm temperate. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 6 is described as mild temperate. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 7 is described as cool temperate. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: NCC climate zone 8 is described as alpine. Checked 16 September 2026.
YourHome, Australian Government: NCC climate zone 1 covers northern Australia from Exmouth in Western Australia across the country to south of Townsville in Queensland. Checked 16 September 2026.
YourHome, Australian Government: NCC climate zone 2 covers coastal Queensland from north of Mackay down to just south of Coffs Harbour in New South Wales. Checked 16 September 2026.
ABCB Climate Map, Australian Building Codes Board: The ABCB climate map gives the NCC climate zone for a location when you search by address or postcode. Checked 16 September 2026.
energy.gov.au, Australian Government: Evaporative coolers work well in low-humidity inland regions, and reduced effectiveness on humid days is listed among their drawbacks. Checked 16 September 2026.
energy.gov.au, Australian Government: Evaporative cooling appears among cooling choices but not heating choices, while reverse cycle air conditioning is described as providing heating as well as cooling. Checked 16 September 2026.
Energy Rating, Australian Government: During the normal operating range in Australia, reverse cycle air conditioners can move three to five units of heat into a room for every unit of electricity they use. Checked 16 September 2026.