Saving money using your boilers and radiators

If you have a combi boiler (i.e. you don't have a hot water cylinder)

Change the flow temperature to the best setting

This change can cut your gas use by 6-8 per cent without changing the temperature in your rooms. Combi boilers work best when they heat radiators at 55°C or below. The temperature that your boiler heats your radiators is called flow temperature and is often set much too high, between 60°C-80°C.

A flow temperature of 55°C means your boiler will be in condensing mode. When your boiler is in condensing mode it can recover heat that would otherwise be lost and run more efficiently.

This easy guide will show you how to change a single setting on your boiler to make it more efficient.

Consider turning down the hot water temperature

You will easily be able to adjust the hot water temperature on your combi boiler – this is the temperature of the water that comes out of your hot water taps.

By default this temperature is often too high. Major energy provider Octopus Energy says a temperature of about 55 degrees should be enough for most.

There should be an option to change the temperature on the front of your combi boiler – usually indicated by a little tap icon. If you're not sure, check your boiler manual. You can then lower it to a temperature you are comfortable with.

Consider turning off the 'pre-heat' function on your combi boiler

Most modern combi boilers have a 'pre-heat' function, so the hot water in your pipes is set at a certain temperature to ensure you don't have to wait too long for your water to heat up.

However, experts at the Heating Hub say while pre-heating is more convenient and less water is wasted, it is hugely inefficient from an energy saving perspective, particularly in homes where the occupants are out at work all day.

So to save cash, check your boiler manual for instructions on how to turn the pre-heat off (it varies per model).

If you have a non-combi boiler

Get a hot water cylinder jacket

If you have a hot water cylinder that is uninsulated (without a cover), it will be losing heat, allowing the water to cool down more quickly. This means you'll be wasting money heating it up again. According to the Centre for Sustainable Energy, fitting a hot water cylinder jacket could reduce heat loss by up to 75 per cent.

It is recommended that you buy a cylinder jacket that displays the British Standard Kitemark. Jackets typically cost around £15 and should be at least 80mm thick.

For most, this will be a DIY job as you just need to wrap it around the hot water cylinder and secure it with string or something similar, but do consult a professional if your tank is hard to reach or you're unsure.

Consider reducing the temperature on your non-combi boiler

If you're able to set two different temperatures on your non-combi boiler, to maximise efficiency Octopus Energy recommends setting your radiator flow temperature to 60 degrees. You should be able to change this on the boiler control panel, indicated by a radiator icon.

Check your boiler manual if you're not sure what to do, and if you're in any doubt, always consult a professional. For your hot water, you should still maintain 70 degrees.

If you have either a combi or non-combi boiler, you can still

Bleed radiators

You should bleed your radiators regularly to prevent air being trapped inside, which will leave cold spots in your radiators. This will make your heating system less efficient, as you'll be using more energy to get adequate heat out of them.

You'll know you need to bleed your radiators if they are taking more time to heat up than usual, you can feel cold patches at the top, or you can hear gurgling noises.

Bleeding radiators is relatively straightforward, but ensure you know what you are doing before you start. Major supplier E.on has a handy guide on how to bleed your radiators.

Keep an eye on your boiler pressure

It's also worth checking the pressure gauge on your boiler regularly. This tells you the pressure of the water circulating in the heating system.

If it's too slow, it'll make your system inefficient, using more energy to heat your home to the required temperature.

The exact recommended pressure level will vary depending on the boiler manufacturer, but generally, anywhere between 1.0 and 2.0 bar is ideal.

On most newer boilers, the pressure gauge will be on the front of your boiler or under the control panel. On older boilers, it may be harder to find.

Check your boiler manual if you can't find it and for help with increasing the pressure. Big energy firm EDF also has a useful guide on how to check your boiler pressure.