Whether it is cheaper to leave a hot water boiler running all day or only switch it on when needed depends on the type of heating system in the home, according to experts at MoneySavingExpert, the consumer website founded by Martin Lewis.
With energy bills continuing to put pressure on households, many people are looking for simple ways to cut back on spending without making too many changes. One question that often sparks debate is whether it is cheaper to leave the hot water boiler running all day or to only switch it on when it is being used.
What's Right for Your System?
For those with a gas, oil or LPG central heating system, it is always cheaper to set the timer so hot water only heats up when needed. Those with a combi boiler could also make savings by lowering their hot water temperature, with around 55°C said to be enough for most households, according to Octopus Energy.
However, things are slightly different for those using an electric immersion heater with an Economy 7 or Economy 10 tariff. These tariffs offer cheaper electricity at night, meaning it is more cost-effective to heat water during those hours rather than throughout the day. The hot water tank needs to be properly insulated to prevent the water from cooling down before it is used.
If unsure which energy tariff you are on, MoneySavingExpert advises checking your latest bill or contacting your energy supplier to find out.
What Do You Do?
Asking this exact question on social media, one user said: "I have an Ideal Logic Air R32, Ideal Halo Air settings tell me to keep the hot water set to 'always on' rather than timed as this saves the most energy."
In response, one user said: "I have mine scheduled to come on overnight (cheap electricity) or around 1pm (using any excess solar if we have had multiple showers). I'm pretty certain that overnight only (with the right tariff) is the cheapest option."
Another user added: "It actually depends on what you've got the temperature drop set to before it comes on to reheat." A third said: "Ours was on all the time and was costing a fortune. It now goes on for an hour at night so its hot for morning showers."
