Thermal curtains for a Cardinia winter.

On a July night in Pakenham the glass in your living room is the coldest surface in the house, and in the hills around Emerald and Pakenham Upper the overnight minimum sits close to freezing. Warm air from the heater travels along the ceiling, meets that cold pane, gives up its heat, becomes denser and falls to the floor. It then runs back across the room as a cold layer along the skirting, which pulls more warm air up and toward the window. That is a convection loop, and it runs continuously for as long as there is a temperature difference. It is the reason a room with the heater on can still feel cold at ankle height.

A curtain does not stop this by being heavy. It stops it by trapping a layer of still air between the fabric and the glass and preventing that air from circulating into the room. Which is why the edges matter more than the fabric weight, and why a modest curtain that seals will outperform an expensive one that hangs loose on a decorative rod.

Lining and fabric options

• Standard lining. Cotton-blend backing that adds body, protects the face fabric from fading, and gives you a second layer of still air. Included in the base curtain price.
• Coated thermal lining. A lining with an acrylic or foam-backed coating that reflects some radiant heat back into the room and resists vapour passing through. $60 to $180 per window over standard.
• Interlining (bump). A soft, brushed layer sewn between the face fabric and the lining. Three layers of cloth means three still-air pockets, plus a much heavier, more sculptural fall. The warmest option we make. $600 to $1,400 per window all up.
• Face fabric weight. Heavier weaves such as textured linen blends and velvets hold more air in the pile. They help, but far less than sealing the edges does.

Where it suits, and where it does not

The rooms worth spending on are the ones you heat. A living room that runs reverse cycle every evening from May to September, a main bedroom, and any room with a large expanse of glass facing south or east. Older established homes in central Pakenham and around Berwick often have single-glazed aluminium frames with generous window area, which is exactly the case for interlining.

Where it is a poor investment: a spare room you never heat, a bathroom, and any window where the curtain cannot be run to the floor because a bench, a bed head or a radiator is in the way. Sealing the top and sides but leaving the bottom open to a sill drops most of the benefit, and you are better off putting the money into a pelmet on the room next door. Thermal linings also do nothing for summer glare on their own, so if the same window bakes in February, look at curtains and blinds together.

How we measure and fit it

Same discipline as any warmth job. The track goes to the ceiling wherever the cornice allows so there is no gap at the top, or to the wall with a pelmet above it. Both ends carry a return that bends the track back to the plaster, so the curtain finishes against the wall rather than hanging in air. Fullness is 2 times the track width, so the panel folds and closes flat. The hem is weighted and finished just clear of the floor. We measure the drop to the floor rather than the sill on every thermal job unless something physically prevents it.

At the measure we also look for water on the glass in the mornings and mould on the reveal. That matters because the newer sealed brick homes across Cardinia Lakes, Arena, Heritage Springs, Lakeside and Riverbank hold moisture, and a tightly sealed thermal curtain keeps the glass colder for longer. The answer is not a thinner lining. It is choosing a lining that suits the room, leaving the curtain able to vent at the bottom or opening it through the day, and keeping background ventilation running. We will say so at the measure rather than after the install.

Lead time and care

3 to 5 weeks from quote approval. Interlined curtains must never go in a washing machine, since three layers with different shrinkage will destroy the hang. Vacuum with a soft brush head twice a year and dry clean only when they genuinely need it. Open them on sunny winter days to let solar gain into the room, and close them at dusk rather than bedtime, which is when the loop starts. For the numbers across every option see the 2026 pricing page, or compare with blockout curtains if darkness is the higher priority.