Evaporative or Refrigerated Cooling? The Honest Trade-Offs for a New Melbourne Home

In short

Evaporative cooling uses water rather than refrigeration. It can be inexpensive to run, but it needs windows or doors open, works best when the air is dry, and does not heat. Refrigerated reverse cycle air conditioning cools a closed-up home and heats it in winter.

With all new Victorian homes built all-electric from January 2027, the deciding question for most new builds is how you will heat the home.

Key takeaways

•    Evaporative coolers cool by evaporating water, work best in low humidity, and need some windows or doors left open while they run.

•    A central evaporative system can use 25 litres of water or more an hour on hot, dry days.

•    Evaporative running costs can be low because only a fan and a small water pump use energy.

•    Heat pumps, including reverse cycle air conditioners, are the most energy-efficient heating and cooling systems you can buy, according to the Australian Government's YourHome guide.

•    From January 2027, all new homes in Victoria must be built all-electric, which puts your heating plan at the centre of the cooling decision.

Evaporative cooling and refrigerated air conditioning both keep a house cooler in summer, but they work in completely different ways and ask different things of the home. If you are building new in Melbourne, the choice also depends on something that has nothing to do with summer. Here are the honest trade-offs.

What is the difference between evaporative and refrigerated cooling?

Evaporative cooling uses the evaporation of water to cool outside air and blow it into the house. Because it keeps bringing outside air in, some windows or doors need to be left open while it runs so the indoor air can escape.

Refrigerated cooling is what most people mean by air conditioning. It removes heat from the air inside your home and moves it outside, cooling to the temperature you set, with the house closed up. It comes as a split system, a multi-split, or a ducted system. Reverse cycle models heat as well as cool with the same system.

Where does evaporative cooling make sense?

Evaporative cooling has real strengths. YourHome, the Australian Government's guide to sustainable homes, notes that operating costs can be low because only the fan and a small water pump use energy, although some units have large or inefficient fans. It suits households that are happy to keep windows open on hot days, like the feel of moving fresh air, and already have their heating sorted another way.

The trade-offs are just as real. The same guide notes that evaporative coolers work best in climates with low humidity, so on muggy days they have less to give. Central systems can use 25 litres of water or more an hour on hot, dry days. Because they draw in large volumes of outside air, their use may need to be limited when outside air quality is poor, such as during bushfires. And a built-in evaporative system can push up winter heating bills, because warm air can escape through its ducting unless the outlets seal or are closed off.

Where does refrigerated cooling come out ahead?

•    Humid days. Refrigerated cooling does not rely on dry air, so it keeps working when the weather turns muggy.

•    A closed-up house. You can keep windows and doors shut, which matters for security, noise, dust and smoky days.

•    Heating as well. A reverse cycle system heats in winter with the same equipment.

•    Room-by-room control. Split systems cool individual rooms, and a zoned ducted system with MyAir zoning lets you switch areas on and off from your phone.

There is a design point for new builds too. If you are building a well-sealed home to hold heat in winter, cooling that relies on open windows works against that design, while a refrigerated system paired with heat recovery ventilation brings fresh air in with the doors shut.

How does the all-electric rule change the decision?

From January 2027, all new homes in Victoria must be built all-electric. Gas ducted heating is off the table for a new build, so every new home needs an electric heating plan, and evaporative cooling does not provide one.

That leaves three common paths, each with a different answer on cooling:

•    Reverse cycle heating (ducted or split). Your heating system already cools. Adding evaporative cooling means a second set of equipment to buy, install and maintain, for a job your system can already do.

•    Hydronic heating from a heat pump. Hydronic radiators or underfloor heating handle winter, so cooling is a separate decision. This is where evaporative or a few split systems both deserve a fair comparison.

•    A hybrid system. Our hybrid systems for new builds use one outdoor unit to power both hydronic heating and reverse cycle air conditioning, so cooling is designed in from the start.

What about running costs?

Evaporative coolers can be inexpensive to run on electricity, but they use water, and some models have large fans that use more energy than you might expect, so check the specific unit. YourHome rates heat pumps, including reverse cycle air conditioners, as the most energy-efficient systems you can buy. For reverse cycle units, the zoned energy rating label lets you compare models: the more stars, the less energy it uses. Zoning and correct sizing matter as much as the label. We do not quote running cost figures without seeing the home, because insulation, glazing and room sizes change the answer.

A quick way to decide

•    Lean evaporative if your heating is already sorted another way, you are comfortable cooling with windows open, and water use is not a concern.

•    Lean refrigerated if you want one system for heating and cooling, a closed-up house on hot days, or reliable cooling on humid days.

•    Compare both properly if you are heating with hydronic. That is the one case where the answer genuinely depends on how you live.

If you have settled on refrigerated and are now choosing the format, read our guide to ducted vs split systems for a new Melbourne home.

Frequently asked questions

What is the difference between evaporative and refrigerated cooling?

Evaporative cooling cools air by evaporating water and needs windows or doors open to work. Refrigerated cooling removes heat from inside the home and moves it outside, so it works with the house closed up, and most modern units are reverse cycle so they heat as well.

Does evaporative cooling work on humid days?

It works less well. The Australian Government's YourHome guide says evaporative coolers work best in climates with low humidity, so on muggy days they deliver less cooling than a refrigerated system.

Does evaporative cooling cost less to run than air conditioning?

It can be, because only a fan and a small water pump use energy. But central systems can use 25 litres of water or more an hour on hot, dry days, and some units have large fans, so compare specific models. Sizing, zoning and how you use the system also change running costs.

Can evaporative cooling heat my home?

No. Evaporative systems only cool. A reverse cycle air conditioner heats and cools with the same equipment, which matters in a new Victorian home that must be all-electric from January 2027.

Your next step

Weighing it up for a new build? Book a free assessment and we will look at your plans, your heating and how you live, and give you a straight answer on the cooling that suits the home. Prefer to start on your own? Take the 2-minute system finder, or call 1300 139 177.