With winter fast approaching, Sydney homeowners are reaching for their remotes and switching their split systems from cool to heat mode. As air conditioning technicians at Gemin3 — servicing homes and businesses across Air Conditioning Sydney every day — we get the same question constantly this time of year: “What temperature should I actually set my air conditioner to in winter?”
The answer might surprise you — and knowing it could save you hundreds of dollars over the cold months ahead.
What’s the Best Air Conditioner Temperature for Winter?
According to Finder’s utilities expert Mariam Gabaji, the sweet spot is between 18 and 20 degrees Celsius. That narrow two-degree margin is your Goldilocks zone — warm enough to feel comfortable, efficient enough to keep your power bill in check.
Here’s the part most people miss: every single degree you push beyond 20°C adds roughly 5 to 10 per cent to your running costs. Over a full Sydney winter, that adds up fast.
It might feel counterintuitive. Most people assume they need to blast the heat to stay warm. But if it’s 5 degrees outside and you’re sitting at 20°C indoors, that’s already a 15-degree difference — you’ll be perfectly comfortable. Trust the thermostat, not the impulse to crank it higher.
Why a Reverse-Cycle Split System Is Your Most Efficient Heating Option
Not all heaters are created equal. As technicians who install and service air conditioning in Sydney homes year-round, we consistently recommend reverse-cycle split systems for one key reason: they don’t create heat — they move it.
Your reverse-cycle air conditioner draws warmth from the outside air (even on cold days, there’s usable heat energy out there) and transfers it inside your home. Energy provider AGL confirms these units absorb heat from outdoor air and use it to heat your interior, distributing warmth across a room far faster than a traditional plug-in heater.
Every other heating type — convection, radiant, gas — has to generate heat from scratch. That’s exactly why they cost significantly more to run.
Winter Heating Cost Comparison: What Are You Actually Spending?
Here’s how common heating options compare for a full winter, according to Finder research:
- ✅ Reverse-cycle split system — approximately $155 for the whole winter
- Electric blanket — approximately 4 cents per hour
- 1,000-watt electric heater — approximately 32 cents per hour
- Convection heater — approximately $270 for the whole winter
- Gas heater — just over $300 for the whole winter
A reverse-cycle air conditioner running at the correct temperature setting costs roughly $115 less per winter than a convection heater, and over $145 less than gas. For Sydney households running heating daily, that’s a significant saving worth paying attention to.
Millions of Aussies Are Going Without Heating This Winter — Here’s Why That’s a Problem
Recent Finder data paints a sobering picture of how Australians are managing rising energy costs. Nearly 80 per cent of survey respondents said they are actively taking steps to keep their electricity bills down — and the humble heater is firmly in their sights.
Close to half (49 per cent) said they would simply wear extra layers rather than turn on the heating, while 45 per cent plan to switch off unused appliances to offset costs. More confronting still, 12 per cent said their heater is going straight into the cupboard for winter — equating to around 1.2 million Australian households going entirely without heating.
Of those who do use a heater, only one in three (36 per cent) are being strategic about it, running it only in the room they’re occupying rather than heating the whole home.
Gabaji summed it up well: going without proper heating isn’t just uncomfortable — it carries real health risks, particularly for older Australians and young children. A reverse-cycle air conditioner set to the efficient 18–20°C range gives you warmth where it matters at the lowest running cost available. It’s the smart middle ground between freezing through winter and watching your energy bill spiral.
Bonus tip: Close off rooms you’re not using and direct your system only to the spaces that need heating. Combined with the 18–20°C setting, this one habit can make a noticeable dent in your quarterly bill.
Stay Warm This Winter Without the Bill Shock — Choose Gemin3 Air Conditioning Sydney
At Gemin3, we believe staying warm in winter shouldn’t cost a fortune. Whether you need a new reverse-cycle split system installed before the cold sets in, your existing unit serviced and running at peak efficiency, or simply honest advice on the most cost-effective heating solution for your home — our team of experienced technicians is ready to help.
We’re local. We’re reliable. And we’re committed to keeping your energy costs as low as your comfort levels are high.
Contact Gemin3 Air Conditioning Sydney today for a free quote and make this your most efficient winter yet.
