What Is a Reverse Cycle Air Conditioner?
A reverse cycle air conditioner is a single unit that can both cool and heat your home by reversing the flow of refrigerant through its system. Unlike a standard cooling-only air conditioner, a reverse cycle unit gives you year-round climate control from one appliance. It is the most common type of air conditioner sold in Australia today, found in everything from small apartments to large family homes.
This article covers everything you need to know before buying one: how the technology actually works, the real benefits over other heating and cooling options, what it costs to run, and what to look for when comparing models.
Key takeaways
- A reverse cycle air conditioner provides both heating and cooling from a single unit by reversing refrigerant flow.
- Reverse cycle systems deliver three to five units of heat for every one unit of electricity consumed.
- They cost significantly less to run than portable electric heaters or gas heating options.
How Does a Reverse Cycle Air Conditioner Work?
A reverse cycle air conditioner works by moving heat from one place to another rather than generating heat from scratch. In summer it pulls heat out of your indoor air and dumps it outside. In winter it does the opposite, extracting heat energy from the outdoor air and transferring it inside to warm your room. Because it moves heat instead of creating it, the system is far more efficient than a resistive electric heater like a bar heater or fan heater.
The process relies on four core components working together in a continuous loop:
- Compressor: Pressurises the refrigerant, raising its temperature so it can release heat effectively.
- Condenser: The coil where the refrigerant releases its heat to either the indoor or outdoor air, depending on the mode.
- Expansion valve: Drops the pressure of the refrigerant rapidly, cooling it down so it can absorb heat from the surrounding air.
- Evaporator: The coil where the cold, low-pressure refrigerant absorbs heat from the air passing over it.
Because the system is moving heat rather than generating it, a reverse cycle unit can deliver three to five units of heating energy for every one unit of electricity it consumes. A 1kW input can produce up to 5kW of heating output. Compare that to a resistive electric heater, which converts 1kW of electricity into exactly 1kW of heat, and the efficiency advantage becomes very clear.
The Role of the Refrigerant
Refrigerant is the fluid that circulates between the indoor and outdoor units, carrying heat energy with it as it changes between liquid and gas states. Without it, the heat transfer process cannot happen. The refrigerant absorbs heat when it evaporates and releases heat when it condenses, which is what makes the whole cycle possible.
Most modern reverse cycle units use R32 refrigerant, which has a global warming potential roughly 68% lower than the older R410A refrigerant it has largely replaced. R32 is also more energy-efficient to use, which contributes to the improved star ratings you see on newer models. If you are replacing an older unit, this is one of the less obvious but genuinely meaningful upgrades you get with a current-generation system. For a full breakdown of how refrigerants work and what the regulations mean for Australian homeowners, see our guide to aircon refrigerant explained.
Cooling Mode vs Heating Mode
Switching between cooling and heating simply reverses the direction the refrigerant flows through the system. A component called a reversing valve redirects the refrigerant so that the indoor coil and outdoor coil swap roles.
In cooling mode, the indoor coil acts as the evaporator. It absorbs heat from your room air and the refrigerant carries that heat outside, where the outdoor coil releases it. In heating mode, the outdoor coil becomes the evaporator. It absorbs heat from the outside air and the refrigerant carries that heat indoors, where it is released into your room.
A common misconception is that reverse cycle heating stops working in cold weather because there is no heat outside to collect. In reality, even air at minus 10 degrees Celsius contains usable heat energy. Most modern reverse cycle units are rated to operate effectively down to around minus 15 degrees Celsius, which covers the coldest nights in virtually every Australian city, including Canberra and the alpine regions of Victoria and New South Wales.
Benefits of a Reverse Cycle Air Conditioner for Australian Homes
Reverse cycle air conditioners are the most popular heating and cooling choice for Australian homes because they handle both jobs from a single unit, run at a fraction of the cost of resistive electric heaters, and include features like dehumidification and air filtration that standalone heaters simply cannot match. Most split system air conditioners available today are reverse cycle as standard, so you are getting all of these benefits without paying a premium over a cooling-only unit.
Here are the four main reasons Australian homeowners choose reverse cycle over the alternatives.
1. Year-Round Climate Control From a Single Unit
One appliance handles summer cooling and winter heating, which means one installation, one remote and one set of running costs to manage. You do not need a separate heater sitting in the corner for six months of the year. For renters and homeowners alike, this simplicity is a genuine practical advantage.
2. Lower Running Costs Than Gas or Resistive Electric Heating
A 2.5kW reverse cycle split system typically costs around $0.25 to $0.40 per hour to run on heating mode, depending on your electricity tariff and the outdoor temperature. A portable electric heater of equivalent output costs $0.50 or more per hour because it converts electricity to heat at a one-to-one ratio. Gas ducted heating is cheaper per unit of energy but requires a gas connection, ongoing supply charges and periodic servicing of the gas system.
Over a full winter, the difference in running costs between a reverse cycle unit and a portable electric heater adds up to hundreds of dollars. Our energy efficiency guide on the blog covers running cost calculations in more detail if you want to work out the numbers for your specific situation.
3. Built-In Dehumidification
In humid climates like coastal Queensland, northern New South Wales and Darwin, moisture in the air makes heat feel far more oppressive than the temperature alone suggests. Reverse cycle units remove moisture from the air as part of the cooling process, which lowers the 'feels like' temperature significantly. Many models also include a dedicated 'dry' mode that runs the dehumidification function without aggressively cooling the room, which is useful on mild but sticky days.
4. Air Filtration on Modern Units
Most current-generation reverse cycle units include multi-stage filtration that captures dust, pollen and other airborne particles as air circulates through the system. Higher-end models from Daikin, Mitsubishi Electric and Fujitsu add activated carbon filters or plasma ionisation to reduce odours and fine particles. This is a meaningful benefit for households with allergy sufferers or pets, and it is something no gas heater or portable electric heater can offer.
Energy Efficiency: COP and Star Ratings Explained
The Coefficient of Performance, or COP, is the number that tells you how efficiently a reverse cycle unit converts electricity into heating output. A COP of 4 means the unit delivers 4kW of heating for every 1kW of electricity it draws from the wall. Most modern reverse cycle split systems have a heating COP between 3.5 and 5.5, which is why they run so much cheaper than resistive heaters with a COP of exactly 1.
The Australian star rating system translates COP and its cooling equivalent (the Energy Efficiency Ratio, or EER) into a simple scale you can compare at a glance. More stars means lower running costs over the life of the unit. The zoned energy rating label also shows an estimated annual energy consumption figure in kilowatt-hours, which you can multiply by your electricity tariff to get a rough annual running cost. When comparing models, always check the star rating for the mode you will use most. A unit with six stars for cooling but four stars for heating is not the best choice if you live in Melbourne and run it on heat for five months of the year. For a full breakdown of how to compare models on efficiency, see our energy efficient air conditioner buying guide.
Reverse Cycle vs Other Heating Options: How Does It Stack Up?
Choosing a heating and cooling solution comes down to upfront cost, running cost, versatility and how well the system suits your climate. The table below compares a reverse cycle split system against the three most common alternatives Australian homeowners consider.
| Heating Type | Upfront Cost | Running Cost (approx. per hour) | Cools as Well? | Energy Efficiency | Best For |
|---|---|---|---|---|---|
| Reverse Cycle Split System | $1,000 to $3,000+ (supply and install) | $0.25 to $0.40 | Yes | High (COP 3.5 to 5.5) | Most Australian homes, year-round use |
| Gas Ducted Heating | $3,000 to $8,000+ | $0.20 to $0.35 (gas) | No (heating only) | Moderate (depends on gas tariff) | Large homes with existing gas connection |
| Portable Electric Heater | $50 to $300 | $0.50 to $0.80 | No | Low (COP of 1) | Occasional use, renters, single rooms |
| Evaporative Cooler | $500 to $2,500 | $0.10 to $0.20 | Cooling only | High for cooling, no heating function | Dry climates (inland Victoria, SA, WA) |
The portable electric heater wins on upfront cost, but that advantage disappears quickly once you factor in running costs over a full winter. A reverse cycle split system costs more to buy and install, but it pays back the difference through lower electricity bills and gives you cooling in summer at no extra cost. Gas ducted heating can be competitive on running costs if you have an existing gas connection and heat a large home, but it requires a separate cooling solution and carries higher installation costs. Evaporative coolers are very cheap to run but only work well in dry climates and provide no heating at all. For a closer look at how evaporative cooling compares to refrigerated air conditioning across different Australian climates, see our article on evaporative vs air conditioner.
For most Australian homes, a reverse cycle split system is the most practical all-round choice. Entry-level options like the Mitsubishi Electric 2.5kW MSZAP25VGKD at $1,040 suit bedrooms and small living areas up to around 20 square metres. Step up to the Mitsubishi Electric 3.5kW MSZAP35VGKD at $1,236 for medium-sized living rooms up to around 30 square metres. For large open-plan areas, the Daikin 8.5kW XL Premium Inverter FTXM85WVMA at $2,909 delivers the capacity and efficiency to handle the load without running up excessive electricity bills.
What to Look for When Buying a Reverse Cycle Air Conditioner
The five factors that matter most when buying a reverse cycle air conditioner are capacity in kilowatts, inverter technology, star ratings, noise levels and Wi-Fi control. Getting capacity right is the single most important decision. Before you compare models, use our guide on what size air conditioner do I need to calculate the right kilowatt output for your room, because an undersized unit will run constantly without reaching your target temperature, and an oversized unit will short-cycle and leave the room feeling clammy.
The table below summarises what to look for across each factor and why it matters.
| Factor | What to Look For | Why It Matters |
|---|---|---|
| Capacity (kW) | Match output to room size and climate zone | Correct sizing prevents short-cycling and ensures the unit reaches set temperature efficiently |
| Inverter technology | All modern split systems are inverter; avoid older non-inverter stock | Variable compressor speed uses significantly less electricity than fixed-speed cycling |
| Star ratings | Check both heating and cooling stars; prioritise the mode you use most | Each extra star reduces annual running costs by roughly 10% |
| Noise level (dB) | Look for indoor units rated below 40dB for bedroom use | A unit running at 45dB or above will be noticeable at night in a quiet room |
| Wi-Fi control | Built-in Wi-Fi or optional adapter for app control | Lets you pre-cool or pre-heat before arriving home, reducing peak energy use |
To give you a sense of what these factors look like across different budgets, here are three concrete examples. The Mitsubishi Electric 2.5kW Split System MSZAP25VGKD at $1,040 is a solid entry-level choice for bedrooms and small living areas up to around 20 square metres. Step up to the Mitsubishi Electric 3.5kW MSZAP35VGKD at $1,236 for medium-sized living rooms up to around 30 square metres. For large open-plan areas, the Daikin 8.5kW XL Premium Inverter FTXM85WVMA at $2,909 delivers the capacity and efficiency to handle the load without running up excessive electricity bills.
Inverter vs Non-Inverter: Does It Matter?
An inverter air conditioner varies its compressor speed continuously to maintain your set temperature, using only as much electricity as the conditions require. A non-inverter model runs its compressor at full power until the room reaches the target temperature, then shuts off completely and repeats the cycle. That constant starting and stopping draws more electricity overall and creates noticeable temperature swings in the room.
In practice, this distinction is largely academic for anyone buying new today. Virtually all reverse cycle split systems sold in Australia are inverter models as standard, so you are unlikely to encounter a non-inverter option unless you are looking at old stock or a very low-cost portable unit. The efficiency gains from inverter technology are real and meaningful, particularly for heating, where the compressor runs for longer periods. For the full breakdown of how inverter technology works and how much it can save on your electricity bill, see our article on what is an inverter air conditioner and is it worth it.
Ready to Find the Right Reverse Cycle Air Conditioner?
A reverse cycle air conditioner is the most versatile and energy-efficient climate control option for Australian homes, delivering both heating and cooling from a single unit at a fraction of the running cost of resistive electric heaters or portable alternatives. Choosing the right capacity for your room size and prioritising a strong star rating for the mode you use most will make a genuine difference to your electricity bills over the life of the unit.
If you are ready to compare models, browse the full range of split system air conditioners on Oz Air Online, where you can filter by capacity, brand and features to find the right fit for your home and budget. Not sure what size you need yet? Work through the room sizing guide first so you go into your purchase with the right kilowatt figure in mind.
Frequently Asked Questions
Which is better, a reverse cycle or split system?
A reverse cycle split system is actually the same thing, and it is the most popular and practical choice for Australian homes. 'Split system' describes the physical setup, with a separate indoor and outdoor unit, while 'reverse cycle' describes the ability to both heat and cool. The vast majority of split systems sold in Australia are reverse cycle, so you get year-round comfort from a single unit.
Is AC good for BP patients?
Air conditioning can be beneficial for people with high blood pressure because it reduces heat stress, which is a known trigger for elevated blood pressure. However, very cold settings or sudden temperature changes may cause blood vessels to constrict, which can work against you. Keeping the thermostat at a comfortable 22 to 24 degrees Celsius is a sensible approach, and it is always worth consulting your doctor for personalised advice.
Does AC dry out your sinuses?
Air conditioners do remove moisture from the air as part of the cooling process, which can dry out nasal passages if the unit runs for extended periods. Setting the unit to a moderate temperature, using dry mode sparingly and keeping filters clean all help maintain better air quality. In very dry conditions, running a humidifier alongside your AC can offset the moisture loss effectively.
Which AC is better for allergies?
Reverse cycle split systems with multi-stage filtration are the best choice for allergy sufferers, as they capture dust, pollen and other airborne particles before recirculating air into the room. Models like the Daikin CORA series (from $997) use streamer discharge technology to break down allergens, while the Mitsubishi Electric MSZ-EF series (from $1,246) features a plasma quad plus filter for fine particle capture. Keeping filters cleaned every four to six weeks is just as important as the filter type itself. Ducted systems can also be fitted with high-grade filters for whole-home allergy relief.