As the UK experiences cold weather, Martin Lewis’ curtain advice around 4pm may help save on energy bills
Households across the UK can take advantage of a straightforward daytime tip championed by Martin Lewis to keep their homes warmer whilst potentially cutting energy costs. As the nation grapples with plummeting temperatures and multiple Met Office snow and ice warnings this week, every penny saved on heating matters more than ever.
The timing is particularly important, as Ofgem’s price cap rose on January 1, 2026, increasing the average household energy bill from £1,755 to £1,758. This change will remain in effect until March 31, 2026.
To help families avoid unnecessary heating expenses, the founder of Money Saving Expert (MSE) has long championed practical strategies, including his mantra of ‘heat the human, not the home’. This approach encourages the use of targeted heating solutions rather than warming an entire property when occupants only use a handful of rooms.
One part of this strategy is a specific winter ‘rule’ that Lewis advises following “rigorously” during the colder months to boost indoor warmth and manage household expenses. Whilst the guidance first emerged during an episode of The Martin Lewis Money Show on ITV a few years ago, its effectiveness endures, offering a quick and practical method for better home insulation.
Martin Lewis’ money-saving team has revisited a simple yet effective energy-saving tip first shared in November 2022, confirming that the advice remains relevant today, saying: “the tips still work”. The strategy centres on a straightforward action to be taken at a specific time each day, potentially benefiting millions of households across Britain, reports the Mirror.
The ‘4pm rule’ explained
“Use tactical curtains,” Martin advised viewers during his programme. These are energy-efficient, thermal-lined curtains specifically designed to retain heat within the home.
Elaborating on the technique, he explained: “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.”
Today, 8 January, sunset occurs around 4pm, varying from approximately 3.47pm in northern regions to around 4.13pm further south. By closing your curtains at these times, you can trap warmth indoors, potentially postponing the moment you need to activate your central heating. As daylight hours gradually extend, remember to adjust this daily routine accordingly.
The principle applies equally to blinds—simply lower them and close the slats for similar results. Warm air typically gravitates towards cooler areas. When a window is left open, the air near the glass cools down, becomes denser, and descends to the floor.
This action draws the warmer air from the ceiling downwards to cool as well, a process known as convection. The presence of a curtain obstructs this air movement, reducing the amount of warm interior air that comes into contact with the cold window.
A University of Salford study found that simply closing your curtains at night can reduce heat loss by 15-17%, and using thermal linings can further improve the effect. To save the most money, open your curtains on sunny days to let in free solar heat, and then close them tightly right after the sun goes down.
How do fleece-lined curtains function?
Fleece-lined curtains operate by forming an insulating layer that traps still air between the window and the room. This design, featuring thick fleece material, decelerates heat transfer, thereby keeping your home warmer in winter and cooler in summer.
If you can afford it, investing in thicker curtains at this time of year could be a wise move. For those on a tighter budget, Martin Lewis and his team propose a cost-effective alternative: attaching inexpensive fleece blankets to your existing curtains as a lining.
They also emphasise the necessity of ensuring the fleece is fire-resistant before proceeding. In addition to curtains, they recommend installing reflective panels behind radiators and sealing any draughts in your home.