The ‘4pm rule’ has been recommended as a way to keep homes warm and cut energy bills
Charlotte Smith Senior Lifestyle Content Editor and Anita McSorley
02:00, 22 Nov 2025
The ‘4pm rule’ could help slash winter heating bills(Image: Getty)
Ireland has been experiencing a significant drop in temperatures recently, with daytime highs barely reaching double digits and overnight lows plummeting to as low as -3C. Frost, icy patches and even snow have become a regular sight across much of the country, and it seems the chilly weather isn’t going anywhere just yet.
Met Eireann has issued a Status Yellow fog warning for 11 counties tomorrow morning, warning that “dense fog in some parts” could lead to “poor visibility and difficult driving conditions”.
As energy bills continue to rise, Irish households are on the hunt for simple ways to keep their homes cosy while also saving money this November. One method that’s gaining traction is the ‘4pm rule’, recommended by Octopus Energy, reports the Irish Mirror.
Money Saving Expert founder Martin Lewis has also given his seal of approval to the rule, stating that it can help keep heat in homes and potentially reduce bills. Although he first mentioned the tip on ITV’s The Martin Lewis Money Show a few years ago, his team reassures on the MSE website that “the tips still work”, despite the segment being filmed in November 2022.
The method itself is quite simple. Octopus Energy advises: “You’ll keep more heat in your home with less energy if you pull your blinds or curtains before it gets dark, up to 17% reduction in heat loss.”
They continued: “Closing curtains in front of external doors can also help to block the cold out and trap the heat in.”
The UK energy supplier advises: “Whilst the sun is shining, keep curtains/blinds open to let in the free heat from the sun. When the sun sets, close curtains/blinds to keep the heat in and the cold out. Curtain liners (or even a shower curtain) can be added during the colder months to thicken existing curtains.”
Today, November 22, the sun will set in Ireland at around 4.15pm. Specialists recommend drawing your curtains at 4pm to capture warmth indoors, which could enable families to postpone switching on their central heating.
Money-saving guru Martin Lewis has shared comparable guidance, urging his audience to “use tactical curtains”. He said: “When the sun is shining, it is letting light and heat into the house, so you want the curtains open. When it gets dark, it’s not, so you want to keep the heat in by closing the curtains.
“I know we all know that, but doing it rigorously can help insulate, especially if you line it with a fleece. There are lots of tips online on how to do that, and really cheaply-do it yourself.”
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