Australian Home Energy Efficiency: Why Power Bills Stay High

We’ve written a lot about heat — about why Australian homes overheat and about the links between heat, health and housing. It’s the story we tell ourselves in this country: Australia is hot, our problem is keeping cool.

But there’s a quieter story that doesn’t get told nearly enough, and this winter I’ve been living inside it. So let me get personal for a moment.

My own home is proof the system isn’t working

I work from home, full-time. I’m also someone who simply refuses to sit in the cold — I don’t think anyone should have to. So this winter, my heater has been on for most of the day.

Here’s the part that should give us all pause: my rental was built in 2022, which means on paper it should be a 6-star energy-efficient home. It has a new split system. I run it at 21°C through the day. My two girls are with me half the time, and when they’re here they’ll flick on the split in their room for a bit in the morning and again at night. That’s it. That’s not extravagant heating — it’s one person working from home who wants to be warm, plus two kids taking the edge off their room morning and evening.

My electricity bills this winter have been between $140 and $200 a month. I actually switched to monthly billing so the cost wouldn’t land as one overwhelming quarterly hit.

Let that sink in. This is a new, supposedly energy-efficient home, and heating it to a comfortable temperature costs that much. If this is what “6 stars” delivers, isn’t that proof the current system isn’t working?

It raises a bigger question about australian home energy-efficiency: if a relatively new home can still be expensive to heat and uncomfortable overnight, are we measuring the things that actually matter?

And here’s the uncomfortable part

I can afford those bills. That’s the privilege I’m very aware of as I write this. But I’m certain a lot of families can’t — and the research backs that up. When heating is this expensive, people don’t keep paying. They turn the heater down, or off, and they sit in the cold. They put on another jumper, close off rooms, and quietly go without.

That’s not a comfort issue. It’s a health one.

And this is where australian home energy-efficiency becomes more than a discussion about energy ratings or reducing household bills. It’s about whether people can afford to keep their homes at a healthy temperature in the first place.

The 18-degree line, and where my home sits

The World Health Organisation puts the minimum healthy indoor temperature at 18°C. Below that, the risks aren’t trivial — cold indoor conditions are linked to higher blood pressure and cardiovascular strain, respiratory problems, and worse mental health. It’s why the WHO names cold housing as a source of unhealthy housing outright.

And Australian homes fail this constantly. Recent research found that around 81% of sampled homes averaged below 18°C across winter, and a study tracking renters found their homes sat below that healthy minimum for an average of more than 17 hours a day. We are, quietly, a nation of cold houses.

My own place isn’t the worst of it — I’ll be honest about that. It’s not an old, draughty weatherboard. But even turning the heaters off overnight when we go to bed and switching them back on in the morning, my home drops to about 13–14°C by morning. Not as brutal as the older housing stock, but still well below what’s considered healthy — and that’s the temperature my kids and I wake up into before the heating catches up.

This is the gap between what we might call australian home energy-efficiency on paper and what people actually experience inside their homes.

This is the flip side of the heat story

We obsess over summer because heat is dramatic and visible. But cold is doing slow, steady harm through winter, and it’s costing people a fortune to hold it at bay — or costing them their health when they can’t.

The maddening thing, as a passive house designer, is that none of this is necessary. A properly designed high-performance home holds a stable, healthy temperature with barely any heating at all. It wouldn’t drop to 13°C overnight; it would still be sitting comfortably above 18°C in the morning without a system running all night. And it would do it for a fraction of what I’m paying — because the building would be doing the work instead of my split system and my bank account.

That’s the whole point of the way we build. Comfort and health shouldn’t be a luxury you buy back, month after month, on your power bill.

Good australian home energy-efficiency should mean more than having an efficient appliance sitting inside an inefficient building. The building itself needs to do more of the work.

The bigger question

My situation is almost a best-case scenario: a newish home, a decent split system, an occupant who can afford to run it. And it’s still expensive, and my home is still cold in the mornings, and it’s still below the healthy line. If the system is failing me on easy mode, what is it doing to everyone with an older home, a tighter budget, or a landlord with no incentive to improve things?

We keep calling it a 6-star system as though the star rating settles the matter. My bills, and my thermometer, say otherwise. A home should keep you warm and well without punishing you financially for the privilege. Mine doesn’t — and it’s brand new.

That’s not a personal complaint. It’s the case for building better, told from my own lounge room with the heater humming in the background.

Maybe that’s the real test of australian home energy-efficiency: not what a house scores on paper, but whether the people living in it can stay healthy and comfortable without constantly paying to overcome the building itself.

And until we start measuring that, we risk calling homes energy-efficient when they’re simply more efficient than what came before.

If you’d like to understand how a high-performance or passive house holds a healthy temperature without the winter bills, we’d love to talk. And if you want more on the other side of this coin, our pieces on home overheating and heat, health and housing are a good place to start.