ComfortGuard
Best temperature for your home when you are away
There is no universal setting that suits every Australian home. The best temperature for your home when you are away depends on the season, the local forecast, insulation, your heating and cooling system, and how long the house will be empty. A comfortable occupied home usually sits around 18–22°C, but an empty house does not need to be held at exactly that temperature.
Your aim should be a stable, moderate indoor environment that protects pipes, furnishings and anything vulnerable without wasting energy. Leaving heating completely off on a cold day can allow pipes and ductwork to chill, while leaving cooling at a very low set point is unnecessary. Small adjustments to the normal occupied setting are usually a better balance.
Three ranges provide practical starting points: about 16–18°C for heating in cool weather, 24–26°C for air conditioning in hot weather, and 20–22°C during mild conditions. The middle of each range is a sensible default, especially if the forecast is uncertain. These targets are not a substitute for advice tailored to unusual buildings or equipment.
Duration matters too. A house empty overnight needs a different response from one left for a fortnight, and a week of forecast heat deserves more attention than a normal weekend away. Households with pets, plants, medical refrigeration, a pool or monitored security systems should build those needs into the decision rather than choose a number from a general rule.
Find the right starting range
Start with the lowest comfortable set point rather than trying to recreate an occupied daytime temperature. In cool weather, leaving heating at 16–18°C can reduce demand while limiting condensation and the chance of pipes becoming very cold. If the home is well insulated, has reliable heating and the forecast is mild, 18°C is an easy compromise; 16°C suits a longer absence or a strong focus on lower bills.
In hot weather, 24–26°C is a useful cooling range. Set it near 25°C, use ceiling fans to improve perceived comfort, and close blinds before the house heats. Lower temperatures can make a split system work harder without making the occupied part of the day any better. If the air conditioner also dehumidifies, a setting around 24°C may be enough to keep the house dry and comfortable.
The selected mode matters as much as the number. A reverse-cycle system on heat and an evaporative cooler cannot provide the same protection. Before relying on a timer or app, learn what your controls actually do. ComfortGuard's system operation videos give you a practical way to check operating guidance, and you can then test the chosen setting while you are still home.
Adjust for Australian seasons
Australia's seasons do not run evenly across the country. In Melbourne, Adelaide, Hobart and much of southern New South Wales, a cold morning can be followed by a mild afternoon, so a heating setting that worked overnight may waste energy later. Time the change to the forecast, and avoid setting the thermostat for the coldest possible moment when the day is expected to warm quickly.
Further north, the challenge is usually humidity rather than just heat. Brisbane, Cairns and Townsville can remain muggy after sunset, and 24–26°C with dehumidification may feel quite different from a dry 26°C. Alice Springs presents the opposite pattern: hot days and surprisingly cool nights, making scheduled heating useful even when daytime temperatures are extreme.
Seasonal mode changes also affect efficiency. Keeping a ducted heater on through a mild week is wasteful, while a cooling system left running in a cool room may short-cycle or create excess condensation. If you are still deciding how to coordinate heating, cooling and schedules, this guide to seasonal HVAC adjustments provides a useful framework for checking each transition before your trip.
Account for how long you will be away
Many households say they will “leave the aircon on”, but that phrase can mean very different things. For an absence of a day or two, adjust the usual set point by only a couple of degrees and use schedules around the likely return. For a week or longer, heating at 16–18°C or cooling at 24–26°C gives a more stable background temperature. The longer the house is empty, the more value there is in remote monitoring, but alerts are not a substitute for a working thermostat.
Think about how heat builds and how the property can drift outside the intended range. An unoccupied room behind a closed door can behave differently from the zone containing the thermostat. Keep the temperature sensor in a representative area, avoid opening the home to an unheated porch or garage, and do not seal every room if the system relies on airflow for circulation.
Some absences have needs that a generic temperature cannot cover. Pets may need a stable warm room, plants may need watering or relocation, and refrigerated medication has strict storage limits that a household thermostat cannot satisfy. Keep essential appliances on reliable power, arrange a house-sitter or emergency contact for long trips, and tell the responsible person what set point is expected rather than expecting them to infer it.
Reduce running costs while keeping control
Energy savings come from avoiding unnecessary extremes, not from switching everything off. Move the thermostat modestly, use the system's efficient operating range, and use blinds and timers to reduce the load. Fans can make a slightly warmer cooling setting feel comfortable, but they add little when the air is already very warm and do not remove moisture. Keep the fridge on its normal setting; unplugging it usually wastes food while offering little useful saving.
Household electricity markets shape the payoff. Most states use retailer tariffs and the National Electricity Market, so the value of shifting heating or cooling to daytime depends on your plan, solar generation and the charges applied to your home. NSW's cooling-off period for embedded generators allows eligible household solar and battery customers to request a period in which they can negotiate connection or disconnection terms with their retailer. Western Australia operates under different market arrangements, so check the local rules rather than assuming interstate options apply.
If solar is on the roof, running the air conditioner during bright middle-of-the-day hours may use some of that generation, but self-consumption depends on your inverter, tariff and household usage. Do not force equipment to run merely to capture a tariff; equipment wear and an uncomfortable house are poor trade-offs. A fixed tariff, a time-of-use plan and a battery can produce very different results, so compare the actual rates and your own usage pattern.
Test the system before departure
Test the setup at least a day before leaving. Run the system on each required mode, confirm the thermostat reaches the set point, check that vents are open and clear, and inspect filters for dust. A neglected filter can restrict airflow, raise energy use and make a system less able to maintain the selected temperature. Make sure the condensate drain is clear if the air conditioner is a ducted unit.
Set the schedule, verify notifications and check the app from outside the home network. If the thermostat, hub or internet connection fails, you want a sensible fallback and someone who can access the property. Change remote-access passwords if needed, but avoid displaying travel dates in a way that advertises an empty house. Keep doors and windows secured and follow the instructions for any security alarm, sensors or monitored systems.
Review the forecast just before departure and again while you are away if alerts are available. During a heatwave, power outage, bushfire warning or smoke event, a fixed set point cannot solve every problem. Know how to operate the system manually, where the breaker is and who can provide help. For a complex system, a qualified HVAC technician can verify controls, drainage and maintenance needs rather than leaving you to troubleshoot after the house has already heated up or cooled down.
For most Australian homes, 18°C is the safest heating starting point and 25°C the easiest cooling setting, with a small adjustment for climate, duration and equipment. A 16–18°C heating range can suit a longer, well-insulated absence; tropical homes may need a slightly higher cool setting if humidity is the concern. Treat these as practical defaults and adjust them using the actual forecast and the way the house performs.
Choose your setting, test it and check the controls before you leave. Then use schedules, monitoring and a trusted contact to make the absence predictable and protect the home without keeping the air conditioning unnecessarily aggressive.