I’ve started closing my curtains early to save energy, and I’ve found one key factor that influences how well this hack works

With nights drawing in and temperatures dropping, I am all for trying an energy-saving hack to keep my bills under control. But does closing curtains early actually save energy at home?

This is a crucial question to answer, especially considering the fact that energy prices rose by 4% in October and are predicted to rise by anywhere between 16 and 25% (depending on the predictions you look at) come January.

Martin Lewis has long advised people to close their curtains as soon as the sun goes down but if you're still waiting to be convinced of the impact it can have on your energy usage, I've started doing it again in my home over the last week, and this is what happened.

Does closing your curtains early save energy?

Yes, closing your curtains early can save energy. It can help to block draughts and reduce heat loss through your home's glazing. This in turn leaves your home feeling warmer, meaning you're less likely to pop your central heating on for an extra hour or two in the evening or use an electric heater or oil-filled radiator for longer than necessary.

Better still, this passive energy-saving method doesn't cost a penny!

'Closing your curtains at dusk is a simple way to help keep your home warm as temperatures drop,' says Stuart Middleton, So Energy's Consumer Energy Expert. 'Windows can be a source of heat loss, so drawing your curtains creates an additional layer of insulation that helps slow the rate at which heat escapes. Thick, well-fitting or thermally lined curtains can be particularly effective.

'The amount of energy you could save will depend on your windows, the type of curtains you have and how well insulated your home is, so it’s difficult to put an exact figure on the savings from this habit alone. However, it’s a simple, low-cost change that can help keep your home comfortable during the colder months without relying as heavily on your heating.'

And I can confirm this hack definitely works. I've long adopted this curtain-closing strategy, and I can definitely feel that my house feels warmer for longer in the evening, without needing to resort to whacking the heating on for another hour.

I measured the temperature in front of my closed curtains and behind them, and found a 2°C difference once the sun had gone down, especially in the rooms where I have thermal curtains. Had my curtains been open, the whole room would have been considerably cooler.

What time should you close your curtains to save energy?

For this hack to work most effectively, you need to close your curtains just before it gets dark. Today, for example, the sun is due to set at 4.52pm where I live, so I set myself a reminder to close my curtains at about 4.30pm. This may get earlier as we get deeper in to winter, so it's worth checking the weather app on your phone for the sunset time.

By closing curtains at this point, you get maximum benefit from any solar gain during the daylight hours, and keep the heat in once the sun goes down and temperatures plummet.

If you tend to be home at this time of day, then setting a reminder on your phone is a pretty simple way to remember to nip round and close the curtains at the optimum time. But what if you aren't?

Fortunately, there is a way to automate your curtain closing. Using a device like the SwitchBot Curtain 3 (£99.99) will allow you to set up schedules to open and close your curtains at the exact time you want, whether you are home or not.

Ideal Home's Digital Editor Becky has been using hers for the last couple of months: 'I added the SwitchBot Curtain 3 to my living room curtains a few months ago and used the schedule function to help control the temperature in my home. In summer, I scheduled them to open when it was cooler and close during the hottest parts of the day. Now for autumn and winter, I've adjusted the schedule so that they close as soon as it gets dark at night to keep the cold out and ensure I always come home to a cosy space.'

Does the type of window treatment make a difference?

In my experience, the kind of window treatment you have makes a big difference to how warm your room remains when the curtains have been closed.

In my home I have a mix of thermal curtains and blinds, fabric or wooden blinds, and standard curtains and I have found there is a marked difference in how well they each keep the heat in.

For me, the best of the bunch by a long shot is my thermal curtains and blinds, followed by my wooden blinds, with my non-thermal curtains and fabric blinds coming in last place. Even though we're not in the depths of winter yet, there was a 2°C difference in front and behind my thermal curtains and blinds, just under a degree difference in front of and behind my wooden blinds, and half a degree in front of and behind my standard curtains.

Fortunately in the rooms I spend the most time, I have these Berlin blackout and thermal curtains from Dunelm (from £15), but I will definitely be upgrading the standard curtains in my guest room before Christmas!