Evaporative to refrigerated conversion in Melbourne, with the roof unit gone for good

Evaporative cooling was the common choice on Melbourne estates for decades because it is cheaper to buy and cheaper to run on a dry day. The trouble is the days it does not work. Evaporative cooling relies on water evaporating into the air, and on a humid afternoon that slows to a crawl: the fan runs, the pads are wet, and the house sits at whatever the outside air feels like. It also needs windows open to work at all, which brings in pollen, dust and street noise, and it does nothing in winter.

Refrigerated ducted reverse cycle cools by removing heat from the air inside the house, so it works whatever the humidity is doing outside, and it takes moisture out of the air rather than adding to it. You set a temperature with the house closed and it holds it. The same unit heats, which means one system, one set of ducts and one controller for the whole year, and for homes that also run a gas ducted heater, a path off gas. There is no water to top up, no pads to replace, no unit to winterise and no drip line running down the roof tiles.

The trade-off is honest: refrigerated uses more electricity to cool than an evaporative fan does, and it costs more to put in. Our reverse cycle versus evaporative guide lays the comparison out, and if a service would get another few summers out of the cooler you have, our evaporative cooler service is the cheaper first step and we will say so.

Roof unit off. The evaporative unit is disconnected, drained, lifted off the roof and taken away, and the water supply and drain are capped. With our height equipment that is a controlled lift, not a wrestle down a ladder.

The opening closed. An evaporative cooler sits over a large hole cut through the roof and the ceiling. That hole is framed, sheeted and flashed over by a licensed roof plumber so it is weathertight, and the ceiling side is closed and insulated so the roof space is sealed again. On a tiled roof that means tiles back in; on a metal roof, a new sheet section or a properly dressed cover flashing.

Fan coil in, condenser out. A refrigerated fan coil unit is hung in the roof space, usually near where the old dropper came down, with a new return air grille in a hallway ceiling so the system can pull air back to the coil. The condenser goes outside on a slab or bracket, joined by insulated refrigerant lines and a condensate drain. A licensed electrician runs the dedicated circuit; an ARC-licensed technician pressure-tests, vacuums and commissions the refrigerant side.

Outlets, controller, zoning. Outlets are swapped or resized for the new airflow, a wall controller replaces the evaporative one, and zoning dampers go in where you want the bedrooms and living areas run separately. Then the system runs in both modes and you get photos of the roof, the roof space and the condenser.

This is the question that decides the quote, so here is the honest version. Evaporative ducts are large, because an evaporative cooler moves a lot of air at low pressure and pushes it out through open windows. Size on its own is rarely the problem; a bigger duct carries air with less resistance. What decides it is everything else. Refrigerated air is cold and the roof space in January is not, so the duct has to be well insulated and its joints sealed or the cooling is lost before it reaches the room. Evaporative ducts were often installed with light insulation, or none, because the air in them was never that cold.

So we assess rather than assume, and on older ducting it is common for more runs to be replaced than kept. Runs that are sound and properly insulated are reused. Runs that are uninsulated, crushed, split or full of the dust an open-window system pulls in over twenty summers are replaced. Outlets almost always change, because evaporative outlets are sized for a torrent of air and refrigerated outlets for a controlled one. And the return air is new either way, because an evaporative system never had one.

Every run is photographed and you get the pictures with the quote, marked keep or replace. If you would rather understand the duct side first, our duct replacement guide explains what a sound duct looks like, and our duct cleaning crews are the people doing the looking.

An evaporative cooler is sized by how much air it can move through the house. A refrigerated system is sized by how much heat it has to remove, which depends on floor area, ceiling height, insulation, glazing, orientation and how many rooms you actually want cold at once. The number on the old roof unit tells us nothing useful about the new one; we size from the house, and our ducted reverse cycle sizing guide explains the method.

Zoning is where the running cost is won back. An evaporative cooler runs the whole house or nothing. A zoned refrigerated system cools the living areas by day and the bedrooms at night, so the compressor is not working for rooms nobody is in. Set it up that way from the start and the compressor only works for the rooms in use, which is what keeps the running cost sensible.

On discounts, plainly: removing an evaporative cooler is not decommissioning a heater, so the Victorian Energy Upgrades discount that applies to replacing a gas heater does not come with an evaporative swap on its own. The program does allow a much smaller discount for a new reverse cycle system with nothing decommissioned, and the office checks whether it applies to your quote. If the home also has a gas ducted heater you are ready to retire, doing both at once is a different job with a different answer: the heater has to be connected, more than two years old and the main heating in the home, and the office quotes it that way, with the discount arranged through our accredited installation partners. See our replace gas ducted heating page.