Thermal and Insulating Curtains: How to Keep Your Home Warmer this Winter

Heating a home through an Australian winter isn't cheap. And if your windows aren't working with you, a good portion of that cost is going straight back outside.

According to energy.gov.au, up to 40% of a home's heating energy is lost through windows, and in winter, bare or poorly dressed windows are often the single biggest source of heat loss in a room. The right window covering won't fix a poorly insulated wall, but it can make a significant difference to how a room feels and how hard your heating system has to work. This guide explains how it works, which products perform best, and why fit matters more than most people realise.

Why windows lose so much heat

When warm air inside your home meets a cold window, it drops in temperature and falls, creating a draught effect even when there are no gaps. This is called cold air pooling, and it's why rooms with large windows can feel cold even with the heating on.

The solution isn't just about blocking draughts. It's about creating a barrier between the glass and the room, trapping a layer of air that slows the transfer of heat. That's exactly what a well-chosen, well-fitted curtain or blind does.

Done properly, the right window covering turns a cold, draughty window into something much closer to an insulated wall.

Not all curtains and blinds are equal when it comes to thermal performance. Here's what to look for.

Thermal-lined curtains are the most effective single product for keeping a room warm. At Victory, we line our curtains and sheers with Thermoguard lining, a 100% blockout specialist thermal backing that creates a genuine air-trapping barrier between the glass and the room. The thicker the curtain and lining, the better the performance.

Blockout curtains with Thermoguard lining do double duty: they keep rooms dark and they insulate. For bedrooms where winter mornings are cold and summer afternoons are intense, this combination is hard to beat. A well-lined blockout curtain makes a noticeable difference to room temperature, and to the comfort of sleep.

Fabric choice matters too. Heavier woven fabrics perform better than lightweight sheers when it comes to insulation, and fabric colour plays a role as well. Darker fabrics absorb more light and convert it to heat, which means a deep charcoal or navy weave will retain warmth more effectively than a pale linen. Our range includes heavy-woven options like the James Donlop Wilderness and Banksia collections, which combine excellent thermal performance with a considered, design-led aesthetic. That doesn't mean you have to sacrifice the look you're after; there are strong thermal options across a wide range of textures and tones.

Honeycomb blinds, also called cellular blinds, are the standout performer among blind options. Their structure is what sets them apart: the hexagonal cells trap air inside the blind itself, creating a genuine insulating layer. Double-cell and triple-cell versions provide progressively better thermal performance. In a room where curtains aren't the right aesthetic choice, honeycomb blinds are the closest equivalent in terms of insulation value.

Standard roller blinds and venetians offer minimal thermal benefit on their own. They're not the right choice if insulation is the primary goal, though they can play a useful role in a layered approach (more on that below).

The custom-fit advantage

This is where a lot of homeowners leave thermal performance on the table.

A curtain that doesn't reach the floor lets cold air pool underneath it and back into the room. A blind with gaps at the sides lets draughts travel past the edge of the fabric. Off-the-shelf options are made to standard dimensions, which rarely match actual windows, and which almost never account for recesses, reveals, or the specific dimensions of a given room.

Custom-made curtains and blinds are cut and fitted to your exact windows. That means:

• Curtains that sit close to the ceiling and fall to the floor, creating a proper seal around the window
• Blinds that fit flush to the recess, eliminating side gaps where air can travel
• No light gaps, no cold spots, no heat loss around the edges

The difference between a correctly fitted curtain and an off-the-shelf approximation isn't subtle, particularly in an older home where windows may not be standard sizes. Getting the fit right is as important as getting the fabric right.

Layering for maximum performance

The best thermal results come from combining products, using a blind and a curtain together rather than choosing between them.

A honeycomb blind fitted to the window recess provides the first layer of insulation, trapping air close to the glass. A full-length thermal curtain in front adds a second layer, more air, more barrier, more warmth retained in the room. In rooms that face south or west, or in homes that are older and harder to heat, this layered approach makes a meaningful difference.

Layering also gives you flexibility across seasons. In summer, the blind alone manages glare and heat during the day. The curtain adds weight and insulation in the evening. In winter, both work together to hold warmth in the room overnight.

It's worth noting that the same logic applies to cooling. A room that retains warmth in winter is also better at staying cool in summer, the same barrier that stops heat escaping in July stops it entering in January. In parts of Australia where summer temperatures are extreme, that's not a small benefit.

A few things worth knowing...

Floor-to-ceiling is better than sill-length. Longer curtains create more barrier between the glass and the room. If insulation is a priority, floor-length is the right choice wherever possible.

Curtain tracks matter. A track or rod that sits close to the ceiling, ideally ceiling-mounted, prevents warm air from escaping over the top of the curtain. Combined with curtains that return to the wall at each end, this approach gets close to enclosing the window entirely.

Pelmets add measurable value. Here's the physics: warm air rises, hits the ceiling, and then travels down the wall toward the window, where it cools against the glass and drops back into the room as a draught. A pelmet, a box or valance fitted above the curtain, intercepts that cycle. By closing off the gap at the top of the curtain, it stops warm air from reaching the glass in the first place, keeping it circulating in the room where it belongs. Our premium curtain range includes pelmet options designed specifically for this purpose. It's one of the most overlooked details in window covering, and one of the most effective.

Our in-home consultants cover all of this as part of a consultation. They'll look at your windows, understand your priorities, and recommend the combination of products and fittings that will actually make a difference, not just look good on paper.

Ready to make your home work harder for you this winter?

Whether you're looking at one room or rethinking your whole home, the starting point is the same: a free in-home measure and quote. We come to you, bring the samples, and give you practical advice based on your actual windows.

No showroom. No obligation. Just good advice in your home.

Book your free measure and quote →