Choosing the right windows and glazing for your home

Most homeowners spend weeks picking a kitchen benchtop or splashback tile, but only a few minutes thinking about windows. Yet windows matter more than people realise. They control how much light gets into your home, and how warm or cool it feels. Choose good quality windows, and your home stays warmer in winter, cooler in summer, and reduce your power bill run for years to come. Choose poorly, and no kitchen will make up for it.

Why most windows let the most heat in and out

Every home has a weak spot for heat loss, and it’s almost always the windows. Walls, ceilings and floors are easy to insulate well if there are no gaps. Glass is much harder. In Tasmania, new homes must meet a minimum energy rating of six stars. Because our winters are cold, most homes here need double glazing. That means two layers of glass with a small gap between them. It’s just the normal choice, not an extra upgrade. Windows can also work in your favour. Placed the right way, they let in free winter sun, which can help lower your heating bills.

How to measure high performing windows

When you compare windows, look past the brand name and check two ratings instead. The first is the U-value, which tells you how much heat can pass through the glass frame. The lower the number, the better the window is at keeping heat inside in winter. A standard double-glazed window sits in the middle of the scale. A top-end triple-glazed window (such as Upvc or timber) scores much lower, but costs more. The second rating is the SHGC, short for Solar Heat Gain Coefficient. It tells you how much of the sun’s warmth comes through the glass. A higher number lets in more free heat; a lower number blocks more of it. In our cold climate, you usually want a low U-value. But the right SHGC depends on which way each window faces. A thermal assessor can work this out for you and give you good advice for the best value window systems.

Which frame material should you choose?

The frame around your glass matters just as much as the glass itself. Here’s how the main options compare.

Aluminium frames: Aluminium is the most common and cheapest choice. It lasts a long time and needs little upkeep. But metal lets heat and cold pass through it easily. On a frosty morning, the frame can feel cold, and you might even get condensation on it. This is where a “thermal break” comes in: a strip inside the frame that stops heat and cold travelling straight through the metal. If you like the look of aluminium but want better performance, ask your glazier about a thermally broken frame.

Timber frames: Timber frames handle heat and cold really well and look lovely. The downside is they cost more and need more upkeep, with ongoing maintenance for paint or sealants. Some timber frames come with a layer of aluminium on the outside. This protects the timber from the weather and cuts down on maintenance, while you still get the warmth and look of timber on the inside.

uPVC frames: UPVC frames are made from a tough type of plastic. They hold in heat well and need little care. Some can turn slightly chalky-looking over time, especially in harsh weather, though better finishes are helping with this. You can also get uPVC frames with a layer of aluminium on the outside, which gives you more colour choices while keeping UPVC’s good thermal performance.

Other frame types: Steel-framed windows show up in a lot of older Tasmanian homes, but steel conducts heat and cold so well that it’s very hard to get a good energy rating out of them today. Fibreglass frames appear occasionally too, but they’re rare, and it can be hard to find a local supplier. For most new builds, the real choice comes down to aluminium, timber or UPVC. Whatever you’re leaning towards, go and look at a real sample in person, not just a photo in a brochure.

Why the direction of your windows matter

Even the best window can’t fix a home that faces the wrong way. In Tasmania, we usually put the biggest windows on the north side, where main living areas sit, because north gets the most sun. East-facing windows get a bit less sun. South and west-facing windows are usually kept smaller, so you don’t lose heat or get too much glare. Roof overhangs help too: they block the high summer sun but still let in the lower winter sun. Bigger windows aren’t always better, either. A wall of glass with no shade can turn a room into a hot, glary space in summer. In winter, that same room can feel cold and draughty. A good designer works out the right amount of glass for each wall. That way, you get plenty of light and a great view, without the downsides.

Cost, timing and mistakes to avoid

Windows can take a long time to arrive once you order them, so decisions need to be made early, well before the build starts. That includes your frame colour, which is usually the same inside and out, so pick that early too. The most common mistakes we see are choosing windows just because they look nice, without checking how well they perform. Another mistake is assuming all double glazing is the same. It isn’t. People also forget to plan around where furniture and the TV will sit. It’s tempting to spend less on windows so you can afford other finishes. But that can quietly cost more in heating and cooling bills for years afterwards. It’s a bit like the hot water system choices we talk, cost, timing and mistakes to avoided about in a past episode. It comes down to weighing the cost now against the money you’ll save later.

Getting the balance right for your build 

Choosing windows and glazing for a new home is about comfort and rules, not just looks. But you don’t have to choose between them. Talk to your building designer early about which way your home should face and how big your windows should be. Bring in a thermal assessor if things get complicated. Lock in your glazier and frame colours early, so long wait times don’t hold up your build. Get it right, and you’ll have a home that’s warm on a cold morning, cool in summer, and still gives you that view you’ve always wanted.

We unpack windows, frames, U-values and orientation in much more detail on Episode 134 of the Building Design Prime Time Podcast. Listen on Spotify or wherever you get your podcasts or head to the contact page to learn how to reach out directly so we can discuss your window and design preferences for your next development project on your property.