Why your Canberra home is too hot in summer and too cold in winter (other than the weather)
If you've spent even one August morning scraping ice off the car while your home's heating system groans to life, or one January afternoon drawing the blinds against the brutal western sun, you already understand Canberra's climate intimately.
Canberra experiences some of the most extreme residential temperature swings of any Australian capital. Summers regularly push into the high 30’s. Winter nights regularly fall well below zero. Many of the families we work with are living in homes built in the 1960s, 70s, or 80s that were designed with almost no consideration for how to work with those extremes — rather than constantly fight them.
The result is homes that are expensive to heat, expensive to cool, and uncomfortable throughout.
Here's what 25 years of designing Canberra homes has taught me about why this happens, and what genuinely fixes it.
It Starts With Orientation
The single most powerful thing we can do to improve a home's comfort and energy performance often costs nothing. It's orientation — which way the home faces — and it has to be designed in from the start (which is why it’s the first thing I look at when evaluation a site).
A home with its main living areas facing north captures the low winter sun beautifully. The sun tracks across the northern sky throughout the day, flooding north-facing rooms with warmth and light during the months you need it most. In summer, the sun is much higher in the sky, and correctly proportioned eaves shade those same windows, keeping the heat out.
This is the fundamental principle of passive solar design, and it's one of the 'freebies' that every Canberra home should exploit. The problem is that many existing homes don't. They were built for a block, often just ‘plonked’ on the site, not placed for the climate. When we're designing an extension or a new home, orientation is the very first thing we assess.
Why Eaves Matter More Than You Think
One of the recent renovation trends we're seeing in Canberra is homeowners removing eaves in new builds or extensions, sometimes for aesthetic appeal and sometimes to save on construction costs. It may seem logical, but this is one of the costliest false economies in residential design and is too often overlooked in Canberra where the focus tends to be maximising sunlight at all costs. Nice in winter, a sauna in summer!
Eaves are what make northern orientation actually work. The geometry is elegant: the summer sun sits high in the sky, and eaves of the correct depth (600mm min., located similar height as window head) shade your north-facing windows completely in summer, preventing heat gain. The winter sun is low, and those same eaves allow it to shine directly in, warming your floors and interior.
Double Glazing: Not a Luxury, a Necessity
Single-glazed windows in a Canberra home are, bluntly, holes in your thermal envelope. The temperature difference between inside and outside during a Canberra winter can exceed 20°C — and single glazing does almost nothing to slow the transfer.
Double glazing used to be the preserve of high-end projects; however hat's no longer the case. As its use has become more mainstream in Australia and as energy efficiency standards are raised, the price gap has narrowed significantly. The performance difference, however, has not. We specify double glazing on every project we design. However, you must also understand that not all double-glazed windows perform equally. Some are a great investment, other are questionable.
The other reality check that a lot of people don’t like hearing is that even super high performance, high-end triple glazing is a big thermal leak in your home, meaning that the best thermal comfort outcomes are achieved by reducing window sizes. This includes north facing windows, which is why we dedicate a lot of time understanding the seasonal impacts of glazing type, size, location and orientation through detailed sun penetration studies, to make sure that you get the right balance of sunlight and shade, views to garden and thermal comfort.
The Floor Plan Is an Energy Decision
Most homeowners think of the floor plan as a layout decision. But every element of the floor plan is also an energy decision.
The shape of your home determines how much external wall you have relative to your floor space, and external wall is where you lose heat in winter and gain it in summer. A compact, well-proportioned home is more thermally efficient to live in. Where rooms are placed also matters — living areas on the north, bedrooms to the east for morning sun is a good outcome, and garages and bathrooms/utility located to the south.
These decisions are made on paper, before a single wall goes up, and they affect how comfortable and affordable your home is to live in for decades.
If your Canberra home isn't working with the climate — and you're ready to change that — reach out for a free 30-minute chat. No obligation, just clarity on what's possible for your home and your family. Call 02 6260 8868