Why Australian Homes Are So Cold in Winter (And What to Do About It in 2026)

Walk into an unrenovated Melbourne home on a winter's morning and the heating's running flat out while you're still wearing two jumpers. The problem isn't the weather. It's the building. And it's the same story right across Australia.

In this episode, Simon Clark, founder of Sustainable Homes Melbourne, breaks down why Australian homes are so cold in winter and exactly what to do about it. From the big stuff to the small stuff people overlook.

Australia's housing stock is old, leaky, and built for cross-ventilation in summer. Most homes have single brick or weatherboard walls with no insulation, suspended timber floors over an uninsulated subfloor, and gaps around every skirting, cornice, and architrave you've ever walked past. You're not just losing heat. You're losing money every single minute the heater is on.

Simon walks through the full hierarchy of fixes: air sealing first (the single biggest bang for your buck in an existing home), ceiling and underfloor insulation, window coverings and glazing upgrades, and how to use north-facing glass to capture free solar gain through winter. He covers zoning — heating where you actually live, not the whole house — and explains why a reverse cycle split system is almost always more efficient than ducted gas for a leaky older home.

You'll learn:

• Why air sealing is the first thing to fix in an existing home, and where the biggest draughts actually hide
• How ceiling and underfloor insulation change the thermal performance of a suspended floor home
• Why zoning matters more than heater size in an older home
• How passive solar gain through north-facing windows can do a lot of the heavy lifting in winter
• The small wins — door snakes, lined curtains, rugs, ceiling fans on reverse — that genuinely move the needle

Who it's for: Homeowners across Australia in older or unrenovated homes who want to be warmer this winter without running the heater all day, and anyone planning a Melbourne renovation who wants to understand the building fabric fundamentals before they start.

If you'd like to know more, please reach out to Sustainable Homes Melbourne or call us on 1800 683 697.

Transcript

SPEAKER_00 0:00

If you're planning to build or renovate and want a home that's sustainable, considered, and built with care, you're in the right place. This is House of Meaning by Sustainable Homes Melbourne, and I'm your host, Simon Clark, Australian builder with a passion for meaningful design. Since 2014, we've had our boots on the ground designing and building homes that are beautiful to live in, thermally comfortable and built to last. In each episode, we'll share practical advice, design insights, and real stories from experts in the industry to help you plan and build your dream sustainable home. Today we're going to talk about how to keep your home warm this winter because Australia's homes are miles behind where we should be. Did you know that more Australians die from cold-related deaths than Swedens do? And this has nothing to do with the weather outside. This has an awful lot to do with the homes that we live in. It's an absolute travesty that Australians deal with every day. There is 11 million homes, roughly, give or take, a few thousand, in Australia, and 60% of those were built before energy efficiency standards came in in 2003. We have around 6.5 million homes that were built before 2003. Let's be generous and say 2 million of those now are upgraded and energy efficient. I'd be surprised if that's the actual fact. So we have 4.5 million homes that have an average energy rating of 1.8 stars. And now the average energy rating today in 2026 that we need to build to is seven stars. So we have an awful lot of Australians dealing with incredibly cold homes. And I want to talk you through five things that you can do to make your home more energy efficient and keep warm this winter. And I will finish off with a couple of, let's say, simple ones. Simple nuts and bolts, ones that you can do no matter where your home is at. If you're living with no electricity or you're living like a hermit, you can apply these into your home and you will get a benefit. Simple things. The first one is air sealing. So just trying to get your home as airtight as practical. So ultimately just reducing that ability for your for cool air to come inside your home. Often old homes in Melbourne and all around Australia really will have gaps at the base between your skirting and your floorboards, even around your windows, and potentially where your wall junctions connect and your ceiling junctions as well. So the simple way to attend to this really is to go to Bunnings or your hardware store and collect some no more gaps or a similar product and seal around those gaps. Windows and doors, of course, that can let obviously if there's a gap under your door, can let a lot more air in. You can get good door seals for that. Depending on how handy you are, you might want to get a trade person to install that. But that is the first thing that I would do for my home, and that is seal up any air leakages that there is. You don't have to worry about getting your home super airtight. Anything you can do really at this point is gonna help keep the warm air in and the cool air out. Number two is insulation. So ultimately, wherever you can get it. Home that I purchased about six years ago now, the first thing we did was insulate under the floors. Insulating under your floors that can improve your home's energy efficiency by about 20%. We recognized improvement nearly straight away. Well, we did straight away the next morning. We woke up, I will admit, we have big, dumb windows in this home. We had big and dumb windows in this home. Just too big, just very, very poor and energy efficient wise and leaky as well. So but we did see that the windows had a layer of condensation on it after we'd installed the insulation underneath, because ultimately we weren't then well cool th wasn't coming up through our floor, it was then coming up and heat travelling out through our windows. So it obviously changed the science or physics of the home there. So it clearly had a great impact. Of course, you can only insulate under your floors if you can gain access, which in a lot of older homes you can. If you can't gain access, apply insulation into your ceiling, that always helps. It certainly helps for heat loss traveling through your ceiling, heat obviously rises, and then of course your walls. Walls can be a little bit more difficult if you're not going to remove cladding or plaster board inside. You can do blow-in insulation, and we've done it on a number of occasions. The problem with blow-in insulation is a lot of the old homes don't have a good wrap on the outside, so they're not the wrap won't contain and all of the blow-in insulation. And then even if it does, you do get a settle. The blow-in insulation does settle over time, so you do get a gap at the top. The old rule of thumb is five percent of gaps in your insulation equal 50% of heat loss. But again, if you do have five percent of gaps, you've still improved the heat loss by 50%. So it's not an ideal scenario, but we're not talking about ideal scenarios here. We're talking about what we can do with what we've got. Ideally, you would remove a cladding or your internal lining and apply insulation. Or if you have double brick, I should say, again, it's another larger renovation type of method, but you there's rigid XPS insulation that you that is on the back of plaster boards called K17 insulation back plaster board from Canalf. You can apply that to your double brick walls. Basically, it takes your double brick wall is basically 0.01, something like that, but it can get that wall to R2.35. So that's if you're looking to do a larger scale renovation. But if you can't do that, insulate where you can, and I would start under your floors in your ceilings, and then I'd go to your walls. Then ultimately, if you've done those three, the next weak spot is your windows. And window upgrades, of course, uh can cost a lot more money, but you can consider that only after you've air sealed, insulated where you can, then I'd go to your windows. But number three is one that's often not spoken about, and it's zoning the home. Now we don't live in all the home all at once, depending on the size. Of course, smaller homes you may be able to heat more economically, but for a larger home, we don't live in all of it. So I'd encourage you to focus on where you do live and zone that aspect of your home. So install sliding doors or hinge doors, whatever it may be, and keep the heating to that area. Bedrooms I don't typically worry about too much. I mean, we do want them at some sort of a moderate temperature, but we have other ways in a bedroom to keep ourselves warm and not cold. And that's course with a duvet. So wherever you're living in the home of an evening after work, you come home, ensure you can have an efficient heating unit in that room and zone it off as best you can. And you know, even if you have to use the snakes under the door to stop that gap, that 10 mil or so gap, do that so then you're not heating the whole home and just wasting it. Now, of course, this is another bigger one, but solar gain. We love to use deciduous trees. So along the north side of a home, we'd often build out an open begola, whether it's a meter, 1200, or two meters, and then we encourage our clients to grow a deciduous viner. What a deciduous vine does obviously is it grows leaves in summer when you want to keep the sun out, and it sheds those leaves in winter when you want to get that sun in. And then ideally, with the sun coming in, you do want that sun to hit a thermal mass. So if it's hitting a timber floor, the timber floor is not really gonna store that heat. But if it's hitting a exposed concrete floor or a brick wall, it will absorb that heat. And then as the home cools of an evening, well, I mean, this is much more important in in summer to be honest. But I mean, we don't we really don't get enough radiant heat in winter, especially in uh areas like Melbourne. Maybe Sydney does, certainly Queensland would, but Melbourne has about a six-hour difference in sunlight from the peak of summer to the depths of winter. So we just don't get enough. But where you can get it, you want it on thermal mass so it can draw that heat out, absorb that heat, then release it into the home. And be very active with curtains and use thick curtains on all windows that are gonna help, especially especially poor performing windows, but all windows, even the best performing windows, are a hole in your insulation. So I would encourage you to install really good curtains or blinds. Honeycomb blinds can work really well, but also some heavy drapes or curtains. Just insulate that home, just another layer to keep that heat within your home. And number five is the heater itself. So we love to use electric hydronic heating, it's the most efficient type of heating, and especially if you've got it in slab. I know it's a larger renovation thing, but in slab, again, the thermal mass stores that heat so you can operate it during the day when the sun's out, and it still holds it of an evening and releases it of an evening. Of course, panels, radiator panels are very, very good with uh hydronic again. And but where hydronic isn't viable, let's say, the next best is really the reverse cycle split systems, they're very energy efficient, they ultimately work on the same technology, which is a heat pump. Of course, they do blow air opposed to being the radiant heat, but they're a great option, especially zoning the home, getting the split system all in the right place and using fans where you can. A home I lived in many years ago, we did it was the way of it in uh Masson Rangers with your big dumb home again, you burn wood. And it's the only way to really keep a home like this warm or bearable, to be honest. And we would run the fan just to spread that through the home. You can do the same thing with a split system. Another one that people often go to is the electric panel heaters, they can work great, they work on the same radiant heating system that the hydronic radiators do, but they draw a lot of energy, a lot of electricity. They are expensive to run, very expensive to run, but they are a lovely heat. My tip would be if you can't do the hydronic electric, I'd be going for the split system. And now, just a couple of small things just to get you by. If you know when people come to us that they often talk about whether they've just purchased a home or have been looking to renovate for many years, they want to do something now just to make their home bearable. I always tell them to hold off if you can. You could consider still installing a split system. We do often remove them. You know, if you're removing a split system, you've got to ensure you're retaining the gas in the split system. Go on to the days of just banging it off the wall and letting the gas go into our ozone layer or our atmosphere. That gas is, I think it's equivalent to tens of thousands of cars on our road each year. It's terrible for our environment. So if you do install a switch system, you can get that removed and then reinstalled into the home. But some other simple things if you're holding out on a large renovation without suffering through the winter, simple things, uh door snakes under your doors, you know, external doors and internal doors where you're zoning the home. Heavy curtains again, like I said, even if you have to put blankets over windows, anything you can do to separate yourself from the external environment, do it. Rugs over timber floors or cold tiled floors can work well. Again, it's just another layer between you and the outdoors. And now, if you do have ducted heating, you know, especially from the roof, ducted vents, close them. Close them in winter so because hot air rises and escapes straight up there. And then another element there that's really over often overlooked. People love skylights, but they act as a thermal chimney. Whatever heat you're creating down here on ground level, you got a skylight above. That's escaping straight out that skylight. And again, a skylight is like a roof window. It's a hole in your insulation layer. We try to avoid skylights wherever we can. If we're going to install them, we install the best we can and put a honeycomb blind on it as well, trying to insulate that skylight as best we can. Move furniture away from in from external walls, just get yourself away from external walls. Ceiling fans on low again, as I as I said before, if you've got a heating source, put the ceiling fan on low. Another big one is the open stairs. Open stairs, people love it again. Now, this is in a lot of new homes that people love. If we are doing an open stairvoid, we would encourage our clients to install a reversible fan in there so that can reverse and instead of that hot air escaping up, it pushes it back down. That can help. And then there's just the simple things of everyday life. Like pets. I remember talking with a client and they felt like their pet was like a one radiator heater. You know, if you're in a crowded place, you get warmth off other people. So pets, the same thing. But pets, blank a blanket of an evening, incredible. If you've got a good comfy seat, watch some television or read a book in a comfy chair of an evening with a blanket over you, cup of nice warm chamomile tea, and you can feel super warm all evening long. And one that's even another one that I'm big on, if we cook in the oven here at my home, we'll always leave after we're finished, we'll leave the oven door down just to let that heat disperse back into the home. Of course, be careful with the cats to jump on it. That's happened once or twice, but we uh we avoid that these days, and that does help just a little bit, just release heat back into the home. So there it is. There's some simple, simple tips, some big, some small. Some you can do today, some you might have to plan for. But I hope these tips help you keep warm during this winter, and maybe someday you can create a home like many of our clients do, that is super airtight, really comfortable with a continuous layer of insulation and uses the most efficient heat sources we can find. All the best, and until next time, this is the House of Meaning. Thanks for listening to the House of Meaning podcast by Sustainable Homes Melbourne. If you got something out of this episode, subscribe so you don't miss the next one. And if you know someone planning a renovation or new build, send it their way. You can find us at sustainable homesmelne.com.au. Thanks for listening. This is House of Meaning until next time.