What does Martin Lewis say about leaving heating on?

So, Martin Lewis – the guy behind MoneySavingExpert.com – gets asked this all the time. Is it cheaper to just leave the heating ticking over on low all day, or blast it when you actually feel cold? His answer's pretty blunt, and it's got physics on its side. Basically, heat your house when you're in it and actually need the warmth. That whole "leave it on low to save money" thing? He's not having it. Total myth.

Why does Martin Lewis say leaving heating on all day is wasteful?

Here's the thing. Martin's argument is dead simple – it's all about heat loss. The longer your heating's running, the more energy you're burning through. Even if it's on a whisper-quiet low setting, your home's still losing heat to the outside. Windows, walls, the lot. So your boiler keeps firing up to top it up. He reckons the boiler actually works harder keeping that steady temp for 24 hours than it does warming the place up from cold once or twice. You're literally paying to heat the street, he says.

"Turn the heating on and off as you need it. Do not leave it on low all day. You are just paying to heat the outside." - Martin Lewis

What is the cheapest way to use central heating according to Martin Lewis?

Right, so what's the game plan? Martin's big on timers and programmable thermostats. Heat your home when you're there and awake, not when you're out or under the duvet. He's got a few practical pointers:

• Heat only when needed: Set it to kick in about 30 minutes before you get up, and cut out 30 minutes before you crash for the night.
• Use a thermostat: Keep the dial at the lowest temp that doesn't leave you shivering – usually somewhere between 18 and 21 degrees. Each degree you knock off can save you roughly 10% on your bill.
• Zone your heating: Got radiator valves? Great. Only heat the rooms you're actually using. Shut the doors on the spare room or the hallway.
• Don't worry about "reheating costs": The energy needed to bring a cold house back up to temp is almost always less than what you'd lose keeping it warm all day. Honestly, don't overthink it.

What does Martin Lewis say about the "boiler on low all day" myth?

God, this one does the rounds, especially with older homeowners. Martin just cuts through it. A boiler's most efficient when it works at full pelt to hit a target temp, then shuts off. Running it constantly on low? You're still burning gas, and the heat's still leaking out through the walls and roof. His analogy's pretty spot on: "It's like filling a bath with the plug out. You wouldn't leave the tap running all day to keep the water warm; you'd just fill it when you want to use it."

Data Table: Heating Strategy Comparison

Checklist: Martin Lewis's Heating Rules

• Only heat rooms you are using.
• Set the thermostat to 18-21 degrees Celsius.
• Use a timer to turn heating on/off.
• Close curtains and doors to trap heat.
• Bleed radiators to improve efficiency.
• Insulate your home (loft, walls, draught-proofing).
• Never leave the boiler on low all day.

Frequently Asked Questions (FAQ)

Expert Insights on Boiler Efficiency

And it's not just Martin. Energy geeks agree modern condensing boilers run best with a lower flow temperature – think 50-60 degrees – and when they cycle on and off. That constant low-level thing? Stops them condensing properly, so you're actually wasting gas. Older boilers? Same principle applies. Heat on demand beats constant heat every time.