Octopus Energy is urging UK households to follow a '4pm rule' to reduce heating bills, a strategy previously endorsed by Martin Lewis. The energy firm advises closing curtains or blinds before sunset to retain warmth, potentially cutting heat loss by up to 17%.
The advice, shared on Octopus Energy's website, recommends keeping curtains open during the day to let in solar heat, then closing them as the sun sets. On November 15, sunset occurs between approximately 3:45pm and 4:25pm across the UK, making 4pm an optimal time to draw curtains.
Martin Lewis first discussed the tactic on ITV's The Martin Lewis Money Show in November 2022. His Money Saving Expert team confirmed the tips remain effective. Lewis advised using 'tactical curtains'—preferably thermal-lined or heavy fabrics like velvet or wool—to insulate windows and block cold air.
For best results, curtains should extend beyond the window frame and reach the floor to create a seal. Adding a pelmet or valance can further prevent heat loss. Octopus Energy also suggests using curtain liners or even a shower curtain to thicken existing curtains during colder months.
