Do curtains and blinds help keep rooms warmer or cooler?
Updated
Yes, they can help. The Australian Government's YourHome guide says blinds and curtains can improve how well a window performs, and are especially useful on existing windows. They work better when they fit snugly with no air gaps around the edges, and a curtain works better when the fabric is heavy or in more than one layer.
The Australian Government's YourHome guide, in its advice on glazing, says window furnishings such as louvres, blinds and curtains can be used to improve the thermal performance of your windows, and are especially useful to add to existing windows. This page sets out what the guide says about how they work, so you know what to ask for.
What makes them work better
- Fit. The guide says snugly fitted blinds and curtains with pelmets trap a layer of still air next to the window, which reduces the heat that moves through the window as air circulates.
- Gaps. The guide says to eliminate air gaps around all edges of the curtain and pelmet to improve performance.
- Weight and layers. The guide says heavy fabrics and multiple layers of fabric help to increase the insulation a curtain gives, by reducing the heat flow between the air in the room and the air next to the window.
- Still air. The guide says this benefit is reduced if there is air movement around the curtain.
| The guide says | Worth asking your retailer |
|---|---|
| A snug fit traps a layer of still air next to the window | How the curtain or blind will sit against the window |
| Close up air gaps around the edges | How the curtain closes off the top and the sides |
| Heavy fabric and more layers add insulation | Which fabric and lining suit the room |
Where lining and track position come in
A lining is a second layer of fabric behind the curtain's face fabric, so it adds a layer at the window. How much an extra layer helps depends on the whole window, including how well the curtain closes it off at the top and sides. Where the track sits changes the gap above the curtain: a ceiling fixed track closes most of it, and a face fixed track usually leaves a gap there.
What they cannot do
The guide says internal blinds are much less effective than preventing the sun's heat from entering the window in the first place. A curtain or blind inside the room is a help, not a cure, and no single result applies to every window or every home. This page is general information, not an energy rating.
Your curtain retailer can talk through the fabric, the lining and how a curtain will sit at your window. Speedy Blinds makes curtains and roller blinds for retailers.
Other ways people ask this
Do thick curtains keep heat in?
The YourHome guide says heavy fabrics and multiple layers of fabric help to increase the insulation a curtain gives. It also says the benefit is reduced if there is air movement around the curtain.
Do blinds keep heat out in summer?
They can help, but the guide says internal blinds are much less effective than preventing the sun's heat from entering the window in the first place.
Do curtains need a pelmet to work?
The guide describes curtains with pelmets as a way to trap a layer of still air next to the window, and asks for air gaps around the curtain and pelmet to be closed up. Ask your retailer how your curtain will sit at the top.
Are lined curtains warmer?
A lining adds a layer at the window. How much it helps depends on the whole window, including how well the curtain closes it off at the top and sides.
This answer is general information. For your own windows, your retailer's advice and your order with them come first.