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Reverse cycle vs evaporative cooling
Short answer
Evaporative cooling uses water and a fan, costs less than half as much electricity as a refrigerated system of similar size, and works well only in dry heat. Refrigerated (reverse cycle) air conditioning cools in any humidity, heats in winter and keeps the windows shut; ducted reverse cycle is about $7,500 to $18,000 installed in 2026.
Prices are estimates, not quotes (how we estimate them). Rebate rules checked September 2026.
Compare 3 quotes for my houseEvaporative coolers push outside air through wet pads. On a dry 38 in Adelaide or Perth they feel like a miracle and the power bill stays small. On a humid Brisbane evening they just move warm soup around the house.
Reverse cycle is a heat pump. It cools and it heats. It dehumidifies. It costs more to buy and a bit more to run than evaporative on those perfect dry days. It works in February and in July.
If you already have evaporative ducts in the roof, a lot of Adelaide and Perth installers will talk about reuse. Sometimes the ducts are fine. Sometimes they are leaky and undersized. Make them prove it, not assume it.
People who work from home in a single room almost always win with a split. People who want the whole house quiet and even, and who also heat with gas, should look at ducted reverse cycle, especially in Victoria.
What is refrigerated air conditioning?
Refrigerated air conditioning is what Perth and Adelaide call a normal air conditioner. It is the same machine the east coast calls reverse cycle, split or ducted air con. The word exists to separate it from evaporative cooling, which was the default in both cities for decades.
"Refrigerated" means it cools with a refrigerant loop. A compressor pumps refrigerant between an indoor coil and an outdoor coil and moves heat out of the house. No water, no open windows. Most refrigerated systems sold today are reverse cycle, which means the same loop runs backwards in winter to heat.
Watch one thing on a WA or SA quote. A handful of older ducted units and some budget quotes are cooling-only refrigerated. If the quote says "refrigerated" and not "reverse cycle", ask whether it heats. In Perth in July, you want the answer to be yes. Our explainer on what reverse cycle air conditioning is covers how the heating side works.
How does evaporative cooling work?
An evaporative cooler is a fan, a pump and a set of wet pads, usually sitting on the roof. The pump soaks the pads. The fan pulls hot outside air through them. Water evaporating off the pads takes heat with it, so the air coming out the other side is cooler and damper. That air is pushed through ducts into the house.
Because it keeps pumping fresh outside air in, the stale warm air has to go somewhere. The federal energy.gov.au guidance is explicit that evaporative systems expel hot indoor air through open windows and doors. Shut the house up and the cooler just pressurises it with humid air.
The physics sets the limit. Evaporation slows when the air already holds a lot of moisture. On a dry 40 degree day in the Perth hills a good ducted evaporative system drops the air a long way. On a sticky 32 degree day in Brisbane it barely moves it and adds humidity you did not need.
Refrigerated vs evaporative: the comparison
| Evaporative | Refrigerated / reverse cycle | |
|---|---|---|
| How it cools | Water evaporating off wet pads | Refrigerant loop moves heat outside |
| Heating | None | Yes, and efficiently (300% to 600%) |
| Humid days | Weak, and adds moisture | Works, and removes moisture |
| Windows | Must be partly open | Kept shut |
| Electricity | Less than half a refrigerated system of similar capacity | Higher for cooling, but the cheapest electric heating |
| Water use | Up to about 25 litres an hour on a hot, dry day | None |
| Bushfire smoke days | Pulls outside air in; limit use | Recirculates indoor air |
| Installed price | Varies by house; we do not price evaporative | $7,500 to $18,000 ducted; $1,500 to $4,800 per split |
| Suits | Dry inland heat, people who like fresh air | Every Australian climate, year-round use |
Refrigerated vs evaporative in Perth and Adelaide
These are the two cities where the argument is real. Summer heat is mostly dry, so evaporative does its job most days, and a lot of homes built through the 1980s and 1990s came with a roof-mounted evaporative unit.
The case for keeping evaporative is running cost and fresh air. The case against is the days it fails you. Perth and Adelaide both get humid spells in late summer when a storm is building, and evaporative performs worst exactly when the nights stay warm. It also does nothing in winter, so those homes usually carry a second system, often gas, for heating.
Swapping to refrigerated reverse cycle gives you one system for both seasons and a house you can shut. It costs more to buy and more to run on a dry hot day. For many families the deciding factor is winter, since reverse cycle heating is cheaper to run than most gas heating at current tariffs. City detail is on the Perth and Adelaide pages, and you can get up to three local quotes to see what the switch costs on your house.
Replacing evaporative cooling with refrigerated ducted
This is one of the most common jobs in Perth and Adelaide. The old unit comes off the roof, the roof penetration is sealed, and a ducted reverse cycle fan coil goes in the roof space with an outdoor unit on the side of the house.
Budget it as a ducted install: $9,000 to $16,000 for a single storey three bedroom home, $13,000 to $20,000 or more for two storey or a tight roof. The ducted cost guide breaks that down. Removal of the old cooler and making good the roof should be a line item on the quote, not a surprise on the invoice. The fastest way to a real number is a local quote from an installer who has been in your roof.
- Ask whether the quote reuses the existing ducts or replaces them. Evaporative ducts were designed to move large volumes of air, not to carry chilled air without condensation. YourHome recommends ducts for refrigerated systems insulated to at least R1.5.
- Ask where the new outlets and return air grille go. Evaporative homes often have no return air path at all, because the windows did that job.
- Ask about zoning. A new system is the cheap moment to split living and sleeping areas.
- Ask for the model's heating capacity, not just cooling. You are buying a heater too.
Bonaire, Breezair, Braemar and Coolair: the evaporative brands
The names you will see on roof-mounted evaporative coolers mostly come from two Australian companies. Breezair, Braemar and Coolair are Seeley International brands, sold as Australian designed and made. Bonaire is a brand of Climate Technologies. Both companies also sell reverse cycle and gas heating products, so the salesperson for your old cooler can quote refrigerated too.
If your old Breezair or Bonaire has started leaking, rattling or smelling musty, you have two choices. Replace like for like and stay evaporative, or use the moment to switch to reverse cycle. We only help with the second, and a local quote for reverse cycle is a sensible thing to have in hand before you pay to repair the old unit. That is not a verdict on the brands. Evaporative units are simple machines and a good one lasts. It is just that the question "what should I heat with" usually comes up in the same conversation.
What is the downside of evaporative cooling?
- It cannot heat. You need a second system for winter.
- It loses most of its punch on humid days, and humid days are common on the east coast and in the north.
- Windows and doors have to stay partly open, which is a problem for security, dust, pollen and bushfire smoke.
- Ducted units can use 25 litres of water or more an hour in hot, dry weather, which matters under water restrictions.
- The pads and tank need regular cleaning, and a neglected unit smells.
- In winter the roof unit and its ducts can leak warm air out of the house unless it has automatic seals or you cover it.
Which should you choose?
- Inland, dry heat, you already heat well with something else, and you like open windows: evaporative still makes sense.
- Brisbane, Sydney, the Gold Coast, the tropics, or anywhere with humid summers: refrigerated reverse cycle.
- Perth or Adelaide, and you also need heating: reverse cycle, split or ducted, usually wins over two separate systems.
- One room does the living: a single reverse cycle split. Size it with the size calculator.
- Replacing gas ducted as well as evaporative: ducted reverse cycle, and check the rebate on your postcode.
Want a number for your house? Check the rebate on your postcode. No name required. Check the rebate on your postcode.
Or do the sums yourself first: what size you need and what it costs to run.
Sources
FAQ
Common questions
What is refrigerated air conditioning?
It is the Western Australian and South Australian name for a conventional air conditioner that cools with a refrigerant loop, as opposed to evaporative cooling. Most refrigerated systems sold now are reverse cycle, so they heat as well. Check the quote says reverse cycle if you want heating.
Is evaporative cooling cheaper to run than refrigerated air conditioning?
Yes, for cooling. The federal energy.gov.au guidance says ducted evaporative coolers use less than half the electricity of an air conditioner of similar capacity. They use a lot of water instead, and they cannot heat, so the year-round comparison depends on what you heat with.
Do I need to leave a window open for evaporative cooling?
Yes. Evaporative coolers push outside air into the house, and the warm indoor air has to escape through open windows or doors. With everything shut the system stops cooling and the house gets humid. Refrigerated systems work with the windows closed.
Does evaporative cooling work in humid weather?
Poorly. Evaporation slows when the air is already damp, so the cooling effect shrinks and the air inside gets wetter. That is why evaporative is common in Perth, Adelaide and inland areas and rare in Brisbane, Sydney and the north.
Which is cheaper to run, a ducted or split system?
A split is cheaper per room. A 3.5 kW split costs roughly 15c to 25c an hour at temperature, while ducted reverse cycle runs about 70c to $1.10 an hour depending on zones open. Our split vs ducted guide has the full comparison.
What is the cheapest way to heat a house in Australia?
For most homes, a reverse cycle air conditioner. Government guidance rates reverse cycle units at 300% to 600% efficient, compared with 100% for a plain electric heater. Gas heating also loses heat through the flue. Heat only the rooms you use and set 18 to 20 degrees.
How much does it cost to change evaporative cooling to refrigerated?
Budget a ducted reverse cycle install, $9,000 to $16,000 for a single storey three bedroom home and $13,000 to $20,000 or more for two storey or a tight roof in 2026. Old-unit removal, roof make-good and any duct replacement should be itemised on the quote.
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