Category - Boilers
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Will Scholfield, Engineer

31 Jan : Updated 18 Apr ● 6 min read

Central heating controls explained: how to use your boiler

Central heating controls can be tricky to understand, especially if you’ve just had a new boiler installed. 

In this guide, we explain how your heating system's different controls work to help your home run more energy efficiently all year long. So, if you’re a bit confused by your boiler’s buttons, thermostat settings and digital display options, you’re in the right place.


Boiler thermostat

Your boiler will have a thermostat controlling the temperature of the water flowing from the boiler to your radiators. 

How does a boiler thermostat work?

Once you set your thermostat, your boiler will heat water to the desired temperature and send it into the radiators to heat your home. 

As it flows through the central heating system and returns to the boiler, the water cools - this is known as the return temperature. 

Reducing the flow temperature can help to save you money on your heating bills as you’ll use less energy, although it may take longer to heat your home. Likewise, if you set your temperature controls too high, you may use more energy but your home will heat up more quickly. 

A standard boiler with a separate hot water cylinder will have a single control for your heating and water flow temperature, usually a simple dial on the boiler. 

A combi boiler, on the other hand, has two separate heating circuits - one for the radiator flow and one for your hot water taps or outlets.  

Remember: do not set your water temperature below 55°C as harmful bacteria can grow that may cause serious health risks. A fixed temperature of 60°C shouldn’t be too hot, and it’ll kill harmful bacteria and stop it growing too. Perfect. 

Room thermostat

Room thermostats are typically located away from your boiler, and should be positioned somewhere centrally in the house to ensure balanced heating to your rooms. 

There are two types of room thermostats: analogue and digital. 

Analogue thermostats are the traditional style of room thermostats, offering a simple dial with less information to understand. Digital thermostats are the newer, more technical version and provide far more detailed insights into the temperature controls of a home. Smart digital thermostats are by far the most energy-efficient and economical option, which makes them a popular choice for most UK homeowners. 

Another benefit of a smart or wireless programmable digital room thermostat is that you can turn the heating on or off remotely without using the settings on your boiler. These thermostats offer more flexibility of control such as holiday modes, frost settings and even learning your heating patterns to optimise energy usage (such as Google Nest Learning Thermostat).

How does a room thermostat work?

A room thermostat has a sensor inside which monitors the air temperature. The central heating system turns off when your home reaches the target temperature and then turns back on again when the room temperature drops. And so, the cycle continues. 

Programmable room thermostats play an important role in saving energy too. Without one, your boiler wouldn’t know when to stop supplying hot water to your radiators, which means you could be wasting energy and heating unnecessarily. 

To avoid wasting energy and keep heating bills down, set your thermostat to around 20°C during the day and between 16°C-19°C at night. 

Discover more energy and money-saving tips about the ideal room temperature in our guide. 

Thermostatic radiator valves

Thermostatic radiator valves are typically fitted to every radiator in your home except one (called a bypass radiator). These valves act as separate temperature controls for each room. 
If you are looking to save money, try putting your radiator thermostats on low in rooms where you spend less time and close the doors on those rooms.

How does a thermostatic radiator valve work?

Thermostatic radiator valves usually have the numbers 1-5 on them. The higher the number, the longer they will stay on in those rooms when the heating is in operation. 

Technically speaking, a thermostatic radiator valve includes two parts - the head and the body. The head contains an actuator that expands and contracts as the temperature increases and decreases. Meanwhile, the valve has a plunger that controls the water supply into the radiator.  

Boiler timer/programmer

Boiler timers let you choose when central heating and hot water will come on during the day. Doing this can help you save energy and make your boiler run more efficiently. 

Depending on the age of your boiler, the timer may be a mechanical tool that needs to be set by hand or have a digital display and use smart technology. Many modern timers/programmers are combined with room thermostats.

How does a boiler timer work?

Your boiler programmer or timer gives you greater control over when your heating and hot water come on, allowing you to manage your heating around the needs of your household. 

If you’re going on holiday, depending on the time of year, you can switch your central heating system off and save money on your energy bills whilst you’re away. Some more advanced timers even have the option to change the settings depending on whether it’s the weekend or a weekday at different temperatures. 

If it’s a winter getaway you’re going on, to avoid the risk of pipes freezing and causing damage to the system, rather than turning your heating off altogether, set your thermostat to 10 degrees. 

What are smart heating controls?

Smart technology gives you greater control over several key appliances in your home, from lighting to security and even your central heating system. 

Smart thermostats enable you to manage your heating from your phone or tablet, even if you’re away. So, if you’re out and you’ve forgotten to switch your heating off, you can do it with just a few taps. You could also switch your heating on, so your home’s nice and toasty for when you get in after a long day at work. 

Check out our smart technology guide and how it can make your life easier.

More advice about your home heating system

Whether you’re looking for a new boiler or you want advice about how to maintain your existing boiler, BOXT is here to help. 

For advice on all things heating, take a look at our selection of boiler guides. Here, you’ll find everything from how to clear an airlock from your central heating system to tips on reducing your gas usage and more. 

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