Do roller shutters actually reduce heat?

Roller shutters can reduce unwanted solar heat gain when they shade the glass from the outside, particularly on windows receiving strong direct sun. The size of the comfort or energy benefit cannot be promised from the product name alone. It depends on climate, orientation, glazing, existing shade, shutter coverage, colour, ventilation, the rest of the building and when the shutter is closed.

Feature, advantage, benefit and limitation

• Adjustable external shading. It can block direct sun before that radiation passes through the glass. This may improve comfort and reduce cooling demand in an exposed room. The limitation is that the shutter must cover the relevant glass at the useful time, and closing it also changes daylight, outlook and ventilation.
• Motorised or scheduled operation. It makes frequent operation easier. The practical benefit is that the shading is more likely to be used before a room overheats. Ask what manual or emergency operation remains available and what the controls, electrical work and warranty include.
• A complete fitted system. Curtain, guides, headbox and installation work together. This can improve shading coverage and usability. Do not treat foam filling, colour or a marketing percentage as proof of whole-window performance; ask for evidence applying to the exact system and test conditions.

What changes the result

Start with the windows that receive unwanted direct sun and the time the room becomes uncomfortable. East- and west-facing glass often needs adjustable or vertical shading because the sun is lower, while useful winter sun may be worth preserving in cooler climates. Compare shutters with other suitable external shading and glazing options rather than assuming one answer fits every elevation.

The Australian Government's YourHome shading guide says shading glazing can materially affect summer comfort and energy use, and that the appropriate design varies with orientation and climate. Ask a supplier to explain the proposed coverage, operation and any performance claim in writing. Treat savings or temperature estimates as assumptions, not guarantees.