How to use a combi boiler efficiently

How to be more energy efficient at home

Have you ever thought about how you could use your boiler in a more efficient way? Perhaps you’ve got your heating temperature set too high or you increase the temperature instead of reaching for a jumper. We’ve come up with some easy ways that you can use your combi boiler more efficiently to reduce your energy usage and bills. 

Reduce the temperature of your home

One of the easiest ways to reduce your energy use at home is to set your thermostat to a lower temperature. According to the Energy Saving Trust, reducing your thermostat by one degree could result in an energy saving of £80 per year, or 320 kg of carbon dioxide. A return flight from London to Glasgow uses 500 kg of carbon dioxide, so this puts into perspective how much 320 kg of carbon dioxide is.

Try turning the temperature down by one or two degrees. You can do this via your thermostat or by adjusting each radiator via their built-in thermostatic radiator valves (TRVs). TRVs don’t control the boiler but they reduce the flow of water that’s passing through the radiator. They’re normally marked with numbers from zero to five. It means that you can set each radiator to a particular heat and maintain the room’s temperature. A lower setting will use less energy.

WDH, a charity that improves people’s living conditions and helps first-time buyers get on the property ladder, has created a table that tells us the average temperature of each setting:

• 0 - 1-6°C
• 1 - 12°C
• 2 - 16°C
• 3 - 20°C
• 4 - 24°C
• 5 - 28°C

You can use this information to gauge the temperature you require the room to be. We’d recommend keeping your radiators on number three for an optimum temperature of 20°C. If you feel cold, find a warm jumper and woolly socks instead of increasing the temperature of the room.

Get a more energy efficient boiler

If your boiler is old and not as efficient as it used to be, it may be time for a new one. There are three main types of boiler that you could consider. These are combi, conventional and system models. You need to think about the size of your house and your heating/hot water demands in order to choose a boiler type and make a purchase.

Gas condensing boilers will most likely be the cheapest and most efficient boilers to run. Newer condensing boilers will run at around 90 per cent efficiency, but this could drop to around 60 per cent as they reach 10 years old.

Check for leaks

To ensure maximum efficiency, you should check your pipes and taps regularly to make sure there are no leaks. Leaks can result in wasted water and may reduce the efficiency of the heating system.

Buy water-saving taps and shower heads

Water-saving taps and shower heads work by limiting the amount of water that flows through them. If you’re using less water, your boiler doesn’t have to heat as much, saving you on both your water and gas usage

Delay turning your heating on

Leaving it until later in the year to start using your heating can save you money too. For example, if you tend to start using it in October, perhaps you could wait until November instead.

By turning your heating on a month later than you would usually, you could save around 5.5 per cent on your energy bill. If you get cold, it may be better to turn a small electric heater on in one room where you spend most of the evening, for example, the living room.

Upgrade your thermostat

If your boiler has an analogue thermostat, you may want to consider upgrading to a wireless digital thermostat. These are easy to control via your mobile phone and you can programme the heating to go on and off as and when you need it.

A digital thermostat could help you to avoid using energy when no one is at home. For example, your heating is set to come on at 7 am and go off at 11 am on a weekend, but you leave the house at 9 am and aren’t due to return until the afternoon. You can use your mobile phone to turn the heating off during the time that you aren’t at home.

Some smart thermostats allow you to control the temperature in individual rooms too. For example, you may want to make your bedroom cooler but keep the living room at a comfortable temperature. This can easily be achieved with a digital thermostat and will reduce your energy usage. 

Don’t heat every room

You may have a guest bedroom or a second living room that is rarely used. These rooms shouldn’t be heated every day. You should set the radiator TRVs to zero and only turn the radiators back on when the rooms are in use.

You might also find that you prefer sleeping in a cool bedroom and it could even give you a better night’s sleep. You may want to consider turning off your radiator in the bedroom and allowing the heat from downstairs to rise and warm this room. 

How efficient is a combi boiler?

Many new gas condensing combi boilers will come with an efficiency rating of up to 98 per cent. This could decrease over time, but is higher on average than the efficiency rating of a conventional system.

A combi boiler will heat the water only when it’s needed, helping to minimise wastage. In contrast, conventional systems may heat up too much water that doesn’t get used, which can be a waste of energy. Combi boilers are ideal for small homes or couple/family homes. If your household uses a lot of water, or has over 20 radiators and more than three bathrooms, a conventional boiler system would probably be more suitable.

Condensing combi boilers are more efficient than older non-condensing designs. This is because they use the heat created by combustion as well as the water vapour that has been produced. Hardly any energy is wasted in this kind of system.

There are lots of ways you can use your combi boiler more efficiently. Many of them are small changes that you may not even notice, such as turning your heating off when you’re not at home and adjusting your thermostat by one degree. But these small changes have the potential to make a big difference to your energy usage.