A comfortable home isn’t just about design — it’s also about how it’s used.
This is a simple story about how small, everyday actions can help a home stay cool in summer and warm in winter.
On one of the hottest days in February, I walked next door to visit my neighbour, Domenica.
Domenica is 89 and her garden is impressive. I never leave empty-handed, with tomatoes, herbs, radicchio, always accompanied by firm cooking instructions. Her latest tip for fried zucchini flowers: use very cold soda water in the batter if you want the flowers crisp.
But that afternoon, it wasn’t the food that impressed me most.
Her house was cool.
Not air-conditioned cool. Just comfortable.
Our houses are similar, built around the same time, with similar construction, and identical orientation. Yet mine was noticeably warmer.
All morning, I’d been reacting to the heat. Windows opened early for a breeze, then shut again. Doors opening and closing as people moved through the house, the kind of rhythm most family homes fall into.
I also live with three very active boys. Someone runs outside, someone forgets to shut the door, someone comes back in two minutes later. The house breathes constantly, whether it’s helping or not.
And of course, this is real life. Doors open, people move, routines aren’t perfect.
Domenica had done the opposite.
The western external blinds were fully down. Internal blinds closed to unused rooms. The kitchen and dining area open but shaded. The doors stayed shut.
The heat never arrived.
She wasn’t cooling the house.
She was stopping it from heating up.
A comfortable home isn’t just designed well, it’s used well
We often talk about passive solar design as if it belongs to the building.
But comfort is something we share with our homes.
This way of thinking is often called passive solar design, using orientation, shading, and natural ventilation to help a home stay comfortable without needing to rely on mechanical systems.
And even a well-designed home works best when we work with it.
Comfort depends as much on how a home is used as how it is built.
The house works best if we work with it
1. Stop heat before it enters
Most overheating in Australian homes is caused by direct sun entering through windows.
Glass lets in solar energy. Once sunlight hits floors, walls, or furniture, the home stores that heat for hours.
Windows are often the weakest part of the building envelope when it comes to heat, which is why what happens at the glass matters so much.
Domenica’s west-facing external blinds stopped the heat before it entered the building.
External shading is one of the most effective ways to reduce heat gain, blocking up to 80–90% of solar radiation before it reaches the glass. In temperate climates like Melbourne, this becomes critical on east and especially west-facing windows, where low-angle sun is much harder to shade and can quickly overheat a home.
Once the sun has passed through the glass, internal blinds can only do so much, which is why external shading is far more effective.
Whether it’s external blinds, eaves, or trees, the principle is the same: shade the glass, and you reduce the amount of heat the home needs to deal with later.
Preventing heat gain is far easier than trying to cool a house later.
The important moment is not when the room feels warm.
It is when the sun reaches the window.
2. Timing matters more than ventilation
People often open windows during hot weather.
But daytime air in summer is often warmer than the air already inside.
Natural cooling only works when outside temperature drops below inside temperature.
In climates like ours, where temperatures often drop in the evening, this is when homes can release the heat they’ve stored during the day, if we open them at the right time.
Homes tend to cool best in cycles:
- closed during the heat of the day
- opened in the evening to release heat
- closed again before the next day warms
Air movement does not always mean cooling.
Temperature difference does.
(This is often called night purging in passive solar homes.)
3. We are part of the system
A house can warm up without direct sunlight.
Cooking, appliances, lighting and people all add heat. Frequent door opening, especially in a busy family home, can also let warm air in and the cooler air out.
On hot days, the goal is simply to keep the cooler air already inside.
The building is not just responding to the weather. It is responding to how it is used.
None of this is about getting it perfect, just about understanding what’s happening so small shifts can make a real difference.
4. Winter is the opposite strategy
In winter, many homes feel cold because they lose warmth quickly.
Summer design keeps heat out.
Winter design keeps heat in.
Open blinds on north-facing windows during sunny winter days to let sunlight in.
Close blinds before sunset to retain warmth overnight.
Comfort comes from storing heat, not continuously producing it.
5. Consistency beats technology
Domenica’s home stays comfortable, partly because her routine is predictable.
Buildings tend to change temperature slowly.
Small, consistent actions can reduce the need for mechanical heating and cooling.
A final thought
Passive solar design is often described as something built into a house.
But it is equally something lived in.
A well-designed home makes the right behaviour intuitive.
And the right behaviour allows a home to perform as intended.
Comfort isn’t just designed into a home.
It’s something we practice every day.
