Following the simple task daily can boost warmth indoors
UK households can benefit from completing a very quick and simple daytime action that Martin Lewis recommends to keep their home warmer and potentially save money on energy bills. This week, the weather has turned bitterly cold, with multiple snow and ice warnings in place from the Met Office.
Ofgem’s price cap also increased this week, meaning the average energy bill for millions of households has gone up slightly from £1,755 to £1,758. The price hike took effect on January 1, 2026, and will remain in place until March 31, 2026.
In a bid to reduce unnecessary costs on central heating, people are urged to make savvy choices at home, including taking on expert advice from the likes of Martin Lewis. The Money Saving Expert (MSE) founder has previously advocated the notion of ‘heating the human, not the home’, using personal heating solutions to avoid spending money on keeping the whole house warm when people will only stay in a couple of rooms.
One aspect of this includes following a specific ‘rule’ “rigorously” in the winter months to boost warmth indoors and help maintain household costs. The ‘rule’ was first mentioned by Martin Lewis a few years ago on his ITV show, The Martin Lewis Money Show. Although the segment aired a while ago, the ‘rule’ still stands today and remains relevant, serving as a handy way to quickly insulate.
On the MSE website, Martin’s team of finance experts said that he spoke about the ‘rule’ back in November 2022, but confirms that “the tips still work”. The ‘rule’ involves doing one specific thing at a certain time of day that will apply to millions across the country.
What is the ‘rule’ and why 4pm?
“Use tactical curtains,” Martin said to viewers watching his show at the time. Tactical curtains are energy-efficient, thermal-lined curtains designed to retain heat. Going into more detail, he continued: “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 cheap to do it yourself.”
The sun is due to set around 4pm today, January 8. Depending on where you live, it’ll set at approximately 3.47pm for people living up north and around 4.13pm for those further south.
By drawing your curtains at these times, you can help trap warmth inside your home, potentially delaying the need to switch central heating on, if desired, until later. As the weeks progress, the times will change, so just bear in mind to adapt this daily habit when needed. The ‘rule’ could also work for anyone with blinds, by pulling them down and closing the slats.
Warm air usually moves to cooler areas. When a window is open in a room, the air near the glass cools down, gets heavier, and falls to the floor. This pulls the warmer air from the ceiling down to cool off, too. This process is known as convection. The curtain blocks this air movement, so less warm air from inside comes into contact with the cold window.
How do fleece-lined curtains work?
Fleece-lined curtains help by creating an insulating layer that holds still air between the window and the room. This design, which has thick fleece material, slows down heat transfer, making your home warmer in the winter and cooler in the summer.
If you have the money, buying thicker curtains at this time of year could be a good investment. Martin Lewis and his team suggest a cheaper option for families on a budget – you can attach cheap fleece blankets to your existing curtains as a lining.
They also stress the importance of making sure the fleece is fire-resistant before you start. Besides just curtains, he also recommends putting reflective panels behind radiators and sealing up any drafts in your house.
