It feels like just yesterday that UK households were being urged to close their curtains on baking hot summer heatwave days. But now, home experts are encouraging people to do the exact opposite as the cold days arrive and the weather turns cooler and wetter and temperatures plunge.
That’s because, despite the colder conditions, closing your curtains in the daytime is actually making your house even colder, which could mean you end up spending more on heating to balance it out. Nancy Whittington-Coates, a window covering expert at Order Electric Blinds, says that during the daytime, sunlight can act as free central heating, even on drab days where it doesn’t seem that sunny. It may sound counterintuitive, but experts say letting the autumn sun stream through your windows could be one of the simplest and cheapest ways to stay cosy as temperatures begin to dip.
Nancy explains: “When it’s cold outside, especially when temperatures drop below freezing, it’s actually best to keep your curtains open while the sun is shining.
This natural warmth comes from what scientists call the “greenhouse effect”. When sunlight enters your home, the glass traps part of that heat, preventing it from escaping too quickly, the same principle that keeps greenhouses toasty even on frosty mornings.
Nancy adds: “The light that comes through your windows can help warm your rooms naturally, even on chilly days. Closing the curtains too early can stop that solar heat gain before it’s had a chance to build up.
“It’s a simple but effective way to make the most of what nature gives us,” Nancy adds. “Even an hour or two of sunshine can make a noticeable difference.”
But once the sun fades, you need to quickly switch tactics.
“As soon as the light fades and the temperature drops, draw your curtains or blinds immediately,” says Nancy.
“That layer of fabric acts as insulation, keeping the day’s heat trapped inside for longer and stopping cold draughts from seeping through the glass.”
The trick, she says, is timing. “Think of your curtains as part of your heating system. They should be open when the sun’s out and closed as soon as it’s gone.
Nancy points out that not all curtains are made equal when it comes to keeping heat in. “If you’re using thin or unlined curtains, you’re losing a big opportunity to retain warmth,” she explains.
“Opt for thermal or lined curtains, or even add a separate lining layer to the ones you already have. It’s a small upgrade that can make a huge difference, especially in older homes where heat loss through windows is more common.”