How Does A Refrigerated Reverse Cycle Heating And Cooling System Work?

A refrigerated reverse cycle heating and cooling system is an electric air conditioner that heats and cools your home with the same equipment. It doesn’t burn fuel to make heat. Instead, it uses a refrigerant to move heat that already exists: from the outside air into your home in winter, and from inside your home to the outside in summer.

That is how one system can heat a Melbourne home in winter and cool it in summer. This guide explains what the word “refrigerated” means, how the refrigeration cycle runs in each season, what each part of the system does, and what to think about before you choose a system for your home.

• A reverse cycle system moves heat rather than making it, which is why one unit can both heat and cool.
• The Australian Government’s energy.gov.au says reverse cycle air conditioners on the Australian market are 300% to 600% efficient.
• Energy.gov.au advises choosing a model with the right capacity for your home and its layout.

What Is Refrigerated Heating and Cooling?

Refrigerated heating and cooling is the Australian name for air conditioning that runs on a refrigerant, the same principle your fridge uses. The Australian Government’s energy advice site, energy.gov.au, describes reverse cycle air conditioning as “an electrical climate-control system that provides heating as well as cooling.” The word “refrigerated” separates it from evaporative cooling, which cools air with water and cannot heat your home.

If you are weighing up the two, our guide to the difference between refrigerated reverse cycle and evaporative air conditioning compares them side by side.

How Does a Reverse Cycle Air Conditioner Work?

A reverse cycle air conditioner works by pumping refrigerant in a closed loop between an indoor unit and an outdoor unit. According to energy.gov.au, air conditioners “do not use electrical power to generate heating or cooling, but rather they use it to transfer heat,” which is how one unit of electricity can deliver 3 to 6 times as much heating or cooling energy.

The refrigerant does the carrying. When it evaporates from a liquid into a gas, it soaks up heat from the air around the coil. When the compressor squeezes that gas, its temperature rises, and it gives the heat up again as it condenses back into a liquid at the other coil. The refrigerant then passes through an expansion valve, drops in pressure and temperature, and starts the loop again.

Cooling Mode in Summer

In cooling mode, the indoor coil is the cold side. Warm air from your rooms passes over it, the refrigerant absorbs the heat, and the cooled air is blown back into the house. The compressor pumps that heat out to the outdoor unit, where the outdoor coil releases it into the air outside. The system also pulls moisture out of the air as it cools, so rooms feel less humid on a sticky day.

Heating Mode in Winter

In heating mode, a part called the reversing valve switches the direction the refrigerant flows. The outdoor coil becomes the cold side and draws heat out of the outside air, even on a cold Melbourne morning. The compressor raises the temperature of that heat, and the indoor coil releases it into your home. The reversing valve is the “reverse” in reverse cycle.

The Components of a Refrigerated Reverse Cycle System

A refrigerated reverse cycle system is built from two units joined by refrigerant pipes. Energy.gov.au describes split systems as “an exterior compressor and an interior unit,” where the interior unit is either mounted on a wall or ducted in the roof cavity and connected to rooms through ductwork. Each part below has one job in the cycle.

• Compressor: this sits in the outdoor unit and pressurises the refrigerant gas, which raises its temperature and keeps it moving around the loop.
• Indoor and outdoor coils: these are the two heat exchangers. One coil absorbs heat and the other releases it, and they swap roles when the system changes between heating and cooling.
• Expansion valve: this drops the pressure of the liquid refrigerant so it turns cold enough to absorb heat again.
• Reversing valve: this changes the direction of the refrigerant so the same system can heat in winter and cool in summer.
• Controller: the wall controller or app tells the system when to run and what temperature to hold in each room or zone.

Energy.gov.au suggests talking to an ARCtick registered licensed technician about the best position for the indoor and outdoor units and how to run a new system efficiently. Beyond Heating and Cooling holds an Australian Refrigeration Council licence, and our licence number is listed at the foot of every page on this site.

Is Reverse Cycle Heating and Cooling Energy Efficient?

Yes. Energy.gov.au states that “the energy efficiency of reverse-cycle air conditioners on the Australian market ranges between 300% to 600% efficient,” because the system moves heat instead of creating it. A heater that turns electricity straight into heat cannot deliver more heat energy than the electricity it uses.

The same government page gives a fair comparison for ducted systems. It says ducted systems “are not as efficient as the wall units, because a larger fan is used, and energy is lost through the ductwork,” and it also says ducted systems “are however more cost-efficient than gas heating.” That second point is why many Melbourne households with an old gas ducted heater look at replacing gas ducted heating with electric heating when the heater reaches the end of its life.

For wall-mounted units, energy.gov.au notes that non-ducted models carry a Zoned Energy Rating Label that rates efficiency for hot, average and cold climate zones. When you compare models for a split system installation, compare the rating for the climate zone your home is in rather than the best number on the label.

How Zoning Works in a Ducted Reverse Cycle System

Zoning divides a ducted reverse cycle system into separate areas of the house, and each area can be switched on, off or set to its own temperature. Motorised dampers in the ductwork open and close to send air only where you want it.

Take a two-storey home with an open living area downstairs and bedrooms upstairs. During the day you can run the living area only, and at night you can switch over to the bedrooms. You are not paying to heat or cool rooms that nobody is using, and each part of the house can sit at a temperature that suits the people in it.

You can read more about whole-home systems on our ducted air conditioning Melbourne page.

How to Choose the Right Reverse Cycle System for Your Home

The right reverse cycle system is one sized to your home, not the biggest unit on offer. Energy.gov.au advises buyers to look for “the model that suits the layout of your house and has the right capacity for your needs.” A system that is too small struggles on the coldest and hottest days, and a system that is too large costs more to buy and runs less evenly.

Several features of your home decide the right capacity:

• The size of each room and the height of the ceilings
• Which way the windows face, and the window coverings
• Whether you want one living area covered or the whole house
• Where the outdoor unit can sit, keeping the noise away from bedrooms and neighbours

Beyond Heating and Cooling offers a free walk-through of your home to plan a new installation. During the visit we measure the rooms, look at where the indoor and outdoor units can go, and explain which type of system suits the layout, whether that is a ducted system, a single split system or several wall units. Our guide on how to size a ducted heating system for your Melbourne home goes into the sizing steps in more detail.

Talk to Beyond Heating and Cooling About a New Reverse Cycle System

If you are planning a new refrigerated reverse cycle system for your Melbourne home, or you want to switch an old heater and cooler to one electric system, contact Beyond Heating and Cooling to book a walk-through. We install from three locations across Melbourne, Craigieburn and Fawkner.

Source: Australian Government, energy.gov.au, “Heating and cooling” (https://www.energy.gov.au/households/heating-and-cooling), retrieved 30 September 2026.