Do Voile Curtains Keep Heat In?

A small amount, but not much, and not in the way thermal curtains do. Voiles add a thin extra layer of fabric across the window, which slightly slows heat loss compared to a bare window, but they are not a serious insulation product. If keeping heat in is the main goal, voiles are not the right answer on their own.

How heat actually leaves through windows

Heat leaves a room through windows in two main ways. Conduction through the glass itself (warm room air heats the glass, the glass heats the cold air outside) and air leakage around the frames where seals have failed. A curtain can help with both, but only if it traps a layer of still air against the glass.

The thicker and denser the curtain, the better the insulation. A heavy thermal-lined curtain creates a meaningful pocket of insulating air against the window. A voile, being lightweight and sheer, traps almost no air at all. The difference in heat retention is substantial.

The Energy Saving Trust estimates that thermal-lined curtains can reduce heat loss through windows by around 15 to 25 percent. A voile alone might offer 2 to 5 percent. Useful, but not a serious solution to a cold room.

When voiles do help with heat

Two situations where voiles do contribute to keeping heat in:

Layered behind main curtains. Where voiles sit between the window and a main lined or thermal curtain, they add a small extra barrier and create a marginal extra air pocket. The contribution is small but real, and over a winter it adds up.

Reducing draughts from older single-glazed windows. A voile pulled across a poorly-sealed window slows down draught movement enough that the room feels warmer even if the actual heat loss reduction is modest. The ‘feel’ of the room improves more than the heat bill drops.

What works better

If the priority is keeping heat in, the products to look at are thermal curtains (curtains made with a thermal-lined or thermal-coated backing fabric), blackout curtains (which usually have a thicker thermal-grade lining), or any lined curtain where the lining adds bulk and density.

For trade buyers (hotels, holiday lets, caravan parks), the standard setup is thermal-lined main curtains with voiles behind for daytime privacy. The thermal curtain does the heat retention. The voile does the daytime light. Each product earns its place by doing one job well.

The honest answer

Voiles are not bought for heat retention. They are bought for daytime privacy, diffused light and a softer window dressing. If a customer asks whether voiles will keep their lounge warmer in winter, the honest answer is ‘a little, but not enough to notice on its own’. Recommending voiles plus a thermal curtain is more useful than overselling what voiles alone can do.

Browse the wholesale voile curtain range at Homefords, or see the thermal curtain range for buyers who need real heat retention.