Evaporative vs Refrigerated Cooling in Melbourne (2026)

These are not two versions of the same appliance. They cool by different physics, and almost every difference in cost, comfort and maintenance follows from that.

An evaporative cooler sits on the roof, draws outside air through pads that are kept wet by a pump, and pushes that cooled air into the house through ducts. Evaporation absorbs heat from the air passing through the pads. The unit consumes electricity for a fan and a water pump, and it consumes water continuously while it runs. Because it is constantly pushing fresh outside air in, that air has to go somewhere, which is where the open windows requirement comes from.

A refrigerated system, whether a split system or ducted, works on a refrigerant cycle. A compressor moves heat from inside the house to the outdoor unit and dumps it there. The house stays sealed, the air is recirculated rather than replaced, and moisture condenses out on the indoor coil and drains away. That is why a refrigerated system dries the air while an evaporative one adds moisture to it.

The consequence is straightforward. Evaporative cooling depends on the outside air being dry enough for evaporation to do meaningful work. Refrigerated cooling does not care what the outside air is doing.

In a genuinely dry climate this comparison is easy and evaporative usually wins. Melbourne is not that climate, and it is not a humid climate either. It is both, often in the same week and occasionally in the same afternoon.

The pattern most Melbourne households know well is a run of hot dry northerlies pulling desert air down over the city, followed by a change coming through from the south west. On the northerly days an evaporative cooler is in its element. The air is dry, evaporation works hard, the house fills with cool moving air, and the running cost is a fan and a pump.

Then the change arrives. Humidity climbs, the temperature may not drop much for several hours, and the evaporative system suddenly has far less to work with. Adding moisture to already humid air produces very little cooling and can make a room feel close and sticky. That is the day people ring us, and it is usually a February evening rather than a January afternoon.

Refrigerated cooling has no equivalent bad day. It removes heat and moisture regardless of what is happening outside, which is why it has become the default across the western suburbs from Werribee through to Yarraville. The trade-off is that you pay more to buy it and more to run it.

This is the practical comparison rather than the brochure one. Where a figure is not given, it is because it varies too much by house, unit and tariff for a single number to be honest.

Evaporative cooling is the cheaper of the two to run on electricity, and that is not a marginal difference. The unit is essentially a large fan and a small pump. There is no compressor, which is the component that dominates the electricity consumption of any refrigerated system.

Against that, evaporative cooling consumes water. It evaporates water continuously while running, and the sump is periodically dumped and refilled to stop mineral salts concentrating in it. On a long hot week that adds up, and in a household on tank water or watching a water bill it is a real cost rather than a footnote.

The other thing to weigh is what you get for the extra electricity a refrigerated system uses. If it is a reverse cycle unit, you are also buying your winter heating. That same box delivers 3 to 4 units of heat per unit of electricity, which is why it heats a room for roughly 28 to 36 cents an hour against 50 to 72 cents for ducted gas, a saving of about $200 to $450 a year for most households. Our guide on cutting winter heating bills works through that in detail.

Read that way, comparing summer running costs alone understates the refrigerated case. An evaporative cooler is a summer only appliance. A reverse cycle system is two appliances in one box, and for a household still heating on gas it is the piece that removes a whole fuel bill.

The open windows requirement is the part people underestimate. An evaporative system pushes a continuous stream of outside air into the house, and that air must be able to leave. In practice that means leaving windows or doors open in the rooms you are cooling. That is fine on a still afternoon in a secure home. It is less fine at night, in a house being left empty, in a windy northerly that slams doors, or for anyone with hay fever, because pollen and dust arrive with the air.

It also means you cannot easily zone an evaporative system by closing doors, which is the free zoning trick that works well on ducted systems. Close the doors and the air has nowhere to exhaust, so the performance drops in the rooms you were trying to cool.

On maintenance, both systems need attention and neither is arduous, but the burden is different. An evaporative unit needs a seasonal service: pads inspected and replaced as they degrade, the sump cleaned, the pump and float checked, and the whole thing drained and covered before winter so it is not sitting full of water through the cold months. Water quality matters, because mineral deposits are what shorten pad life.

A refrigerated system is mostly filter cleaning, which is a five minute job people still neglect. A blocked filter makes the fan work harder to move less air, which shows up as poor performance that gets blamed on an undersized unit. Beyond filters, the coils want an occasional clean and the system wants a periodic professional service. Any work on the refrigerant circuit itself requires an ARC licence, and the electrical connection requires a licensed electrician issuing a Certificate of Electrical Safety. Both apply on installation as well.

Evaporative is generally the cheaper of the two to buy and install for whole house coverage, because the unit itself is simpler and there is no refrigerant circuit to charge and commission. The install involves a roof mounted unit, ducting through the roof space to ceiling outlets, a water supply run to the unit and a controller inside.

Refrigerated is quoted differently depending on whether you go split or ducted. A split system runs $2,500 to $7,500 installed depending on capacity and how many indoor heads are involved. A single head covering a living area sits near the bottom of that. A multi head system covering a living area and two bedrooms sits nearer the top. Ducted refrigerated cooling is a larger job again and is quoted per house, because duct sizing, return air and zoning all vary with the building.

One item worth raising early is the switchboard. A refrigerated system needs a dedicated circuit with appropriate protection, and on older homes across the west that sometimes means a switchboard upgrade before anything else happens. It is far better to find that at quote stage than on install day, which is why the board is part of our site assessment.

If you already have a functioning evaporative system, the honest advice is usually to keep running it and replace it with refrigerated when it reaches the end of its life rather than before. A working appliance that costs very little to run is not a good candidate for early replacement, and the change days it struggles on are a minority of the summer.

If you are choosing from scratch, the question is what you want the system to do on the worst day rather than the average one. Cooling is bought for heatwaves and for humid nights, not for mild afternoons when a fan would do.

For most households in Melbourne west we end up recommending reverse cycle, because it covers both seasons, it works on every kind of hot day, and removing a gas heating bill is a larger saving than the summer running cost difference. Where evaporative still makes clear sense is in larger homes with high ceilings and good cross ventilation, in households that genuinely prefer fresh moving air over sealed conditioned air, and where the budget for whole house coverage is the binding constraint.

The full heating and cooling range is worth a look before you decide, and if you want a straight opinion on your specific house rather than a general one, get in touch. We fit and service both types across the western suburbs, so we have no reason to push you toward one.