Zone 2 is described as warm humid summer, mild winter. energy.gov.au says evaporative coolers become less effective as humidity rises, which is why humid zones lean on refrigerated air conditioning.
An estimate from a published rule of thumb and price guides, not a quote. Full output is the ceiling: inverter systems
spend most of their time below it.
How this estimate is built
Four published figures do the work here, and none of them is ours. Capacity comes from Canstar Blue's rule of
thumb, 0.12 to 0.15 kW per m²↗ of floor area. Split system prices come from CHOICE: $600 to $5,500↗
for the unit and $600 to $800 or more↗ for the installation. Ducted prices come from the same guide,
starting from about $5,000↗ for a small home.
Running cost starts with efficiency. Energy Rating says a reverse cycle system moves 3 to 5 units of heat per unit of electricity↗,
so the power drawn is the heat you want divided by that. Multiply by your own usage rate and you have dollars per
hour at full output.
Why does it ask for your electricity rate?
Because we could not verify a single national tariff worth printing, and a wrong default would quietly make every
dollar figure on the page wrong. Your bill has the number, usually labelled as the usage or peak rate.
What the estimate cannot know
The rule of thumb ignores ceiling height, orientation and glazing↗. It also assumes full output, which an inverter system rarely
runs at for long. Treat the result as a way to judge a quote, not as a quote.
Where the discounts come from
Victoria's figures are the Victorian Energy Upgrades maximums for replacing gas heating, up to
up to $5,530↗ for ducted gas. New South Wales publishes up to $550↗ for a new 6 kW
system. Queensland has nothing open: the state rebate is closed↗.