Following the ‘rule’ daily can help keep your home warmer in the evening
11:11, 20 Nov 2025Updated 11:11, 20 Nov 2025
Ocotpus Energy has shared the same advice as Martin Lewis once did(Image: ITV/Getty)
Octopus Energy is recommending a ‘4pm rule‘ to UK households as the weather turns colder and utility bills remain high. The ‘rule’ has made headlines previously for also being recommended by Money Saving Expert (MSE) founder Martin Lewis, who says it can help keep heat in and potentially lower bills.
He first talked about it on ITV‘s The Martin Lewis Money Show a few years back, but with the cost of living crisis still keeping a tight grip on UK homeowners, it’s still relevant. His team of experts on the official MSE website also confirmed that even though the segment was filmed in November 2022, “the tips still work”.
The method involves following a certain ‘rule’ at a specific time each day to maximise heat in your house without needing to rely on costly central heating too much. Outlining the ‘rule’ on its website, Octopus Energy says: “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.”
It continued: “Closing curtains in front of external doors can also help to block the cold out and trap the heat in.” Explaining what to do, the energy supplier said: “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 15, the sun will set between approximately 3.45pm and 4.25pm, depending on your location. Experts suggest closing your curtains around 4pm to retain the warmth inside your home, which may help you delay turning on your heating.
The advice is extremely similar to the tip Martin Lewis previously spoke about. At the time, he told viewers: “Use tactical curtains.” He meant energy-efficient curtains that help keep the heat in; these are usually thermal, lined curtains.
He added: “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.”
Keeping windows covered when it gets dark can help trap heat inBest curtains for keeping the heat inside
The best curtains to keep heat inside are thermal-lined ones made from thick, heavy materials like velvet or wool. These fabrics work really well to block the cold from windows. Choose heavy fabrics with a high thread count, like velvet, suede, or wool blends. These types of materials are naturally better at keeping heat in compared to lighter fabrics like silk or linen.
The secret to how well thermal curtains work is in their lining. Make sure to look for curtains that have a special thermal or blackout lining. This lining usually has several layers of fabric, sometimes with foam or a rubbery back, which helps trap air and slow down the heat from escaping.
To get the best results, make sure your curtains fit your window properly. They should hang a few inches past the edges of the window frame and go all the way down to the floor. This helps create a good seal and stops cold air from coming into the room. Putting up a pelmet or valance at the top of the curtain rod can also help keep the heat in by stopping air from flowing over the top.