Should You Turn Your Boiler On & Off?

Turning your boiler off at night and back on in the morning may seem like a great way of saving energy and therefore money, however, you may not be saving any money at all.

Why people turn off their boilers

A common belief for turning off the heating at night is that once you’re snuggled up in bed, you’ll be warm enough without heating, particularly if you have insulation and double/triple-glazing and you won’t be using any hot water whilst asleep, so what’s the point in keeping the heating on?

Another reason for people turning their boiler off is to avoid reheating the heat exchanger for hot water when you aren’t using it during the night.

Some people don’t use their hot taps a lot in the morning either as their showers heat water on demand and the kettle uses cold water.

So other than waiting for the radiators to warm up, is there a point in leaving the boiler on overnight?

The negatives of turning it off overnight

Whilst the arguments above make sense, you should consider a few things first before doing the same.

The first thing to consider is how well insulated your home is. If you have cavity wall insulation, loft insulation, double/triple-glazed windows and decent sealing around your windows and doors, your home may well retain its heat for a good few hours after the heating is turned off.

However, if you are lacking any of these, your home’s warmth could drop drastically.

Whilst this may not bother you once you’re asleep, it can lead to more serious issues such as damp walls as water vapour condenses on them, which not only causes heat loss but can lead to structural or cosmetic damage that can be costly to fix.

In extreme circumstances, your pipes may even freeze over which is far more expensive and inconvenient to solve.

Another thing to consider is the cost of having to raise the temperature every morning.

If your home has decreased to 10°C, your boiler will have to work extra hard to raise it to a comfortable 18-20°C, which could take just the same amount of energy as leaving the thermostat at 15°C throughout the night and therefore not really saving you any money at all.

How to use your thermostat and timer effectively

A useful way to practically turn your boiler on and off without isolating the power is by using your thermostat and timer effectively.

A method of ‘turning off’ your heating is by setting your thermostat to its minimum before going to bed. This means it will be unlikely for the heating to come on unless your home dramatically drops in temperature.

An alternative method is to set the thermostat in its middle range e.g. 12-14°C. Most nights, your heating won’t come on, however, this does provide you with a safeguard for when the temperature gets extremely cold.

Most modern boilers come with a timer which can be controlled by a separate panel to the boiler itself.

This allows you to schedule the boiler’s behaviour for each day of the week. The timer overrides the thermostat, so if you have scheduled the boiler to turn off at 11pm and the temperature drops below the thermostat’s settings, it won’t come on.

You may hear your boiler fire up from time to time, though this is simply part of the preheating process and you may otherwise find yourself having to run the hot tap for 60 seconds before any hot water comes out, which is a bad thing if you’re trying to save water.

Should you switch it off when you go on holiday?

Unless you still have an old model of boiler with a gas pilot light (flame) that consumes energy, it isn’t wise to switch your boiler off entirely when you go on holiday.

If you set your thermostat to its lowest temperature, the boiler shouldn’t turn on whilst you’re away.

Leaving your boiler on also means your house won’t be incredibly cold when you return and also stops the pipes from freezing over if the temperature drops whilst you’re away.

If necessary, turn off the production of hot water to stop your boiler from constantly running if you have a hot water storage tank or separate water heater as opposed to a combi boiler.