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What temperature should my combi boiler be set at?

an installer showing a couple in the kitchen how their boiler works

What you'll learn

  • What does the temperature of your boiler mean?
  • What settings should my combi boiler have?
  • How to set your boiler temperature
  • Tips for efficient heating of your home

What does the temperature of your boiler mean?

When we reference the temperature of your boiler, we are actually discussing the temperature of the boiler itself, not the level of a thermostat or target heating temperatures for rooms in your house. The most important thing to remember, is that these are unique - the boiler needs to heat to a specific temperature in order to heat the rest of your home, and that operation is defined by the thermostat you set for your home.

a combi boiler in a kitchen

What settings should my combi boiler have?

The exact temperature setting for a combi boiler is not set in stone, though there are some generally accepted guidelines for efficient operation and heating performance.

For a modern combi boiler, the radiator heating temperature should be set for a flow temperature of between 60 and 70°C. Any higher than this and the boiler won’t enter condensing mode and be at its optimum efficiency and performance. In spring and Autumn months, consider reducing the boiler’s radiator temperature further - to around 50 or 55°C, as this will provide additional efficiency at the cost of heating performance. As an additional note, this temperature setting refers to the temperature of the water inside the radiators whilst heating your home. Depending on your home, for example if you have done some fabric improvements since the original heating system was installed, it may be possible to leave the setting at between 50 to 55°C even during winter. The lower the heating flow temperature, the more efficient the heating system - lowering your gas consumption and consequently running costs.

Meanwhile, we recommend the hot water temperature to be set at around 50°C. Anything over 45°C at the point of use (tap or shower) can cause scalding so would need to be mixed down with the cold water. This setting should again provide an ideal balance of heating performance, comfort and efficiency for the majority of homes.

How to set your boiler temperature

Adjusting the radiator and water temperature on a modern Vaillant combi boiler is quick and simple. Our modern boiler systems come equipped with a user control panel and LCD screen to facilitate adjusting the temperature, where individual settings can be input for your water and radiator temperature.

The actual process may vary depending on your specific model, so we recommend referring to your user manual for specific guidance. With that said, many of our systems will have a button for the radiator temperature and hot water temperature. Once pressed, you can increase or decrease the temperature in 1 degree celsius increments to your desired setting.

Tips for efficient heating of your home

To ensure you get the most efficient use of your home's heating system, there are a number of things you can do to get the most out of your boiler.

  • Lowering your thermostat in your home can greatly improve efficiency

    Dropping the thermostat temperature within your home is one of the best ways to ensure your home heating is efficiently managed. Even just a difference of 1 degree celsius can have a large impact in your overall heating bills. Generally, anywhere between 19-21 degrees celsius should be comfortable for most homes.
  • Bedroom temperature should be set lower than the rest of the house

    It’s highly recommended to ensure your bedroom thermostat temperature is set to a lower value than the rest of your home - typically by 2 degrees celsius. This is to ensure optimal sleeping conditions for most people. As a note, if you do not have individual room thermostat functions, you can use a timer to increase the temperature during the day and reduce the temperature during the night in order to reach your desired settings.


Many people will not need to adjust their boiler temperature directly, though if you’re finding it takes too long to heat your home, the water is not at your desired temperature, or the radiators are uncomfortably warm when active, adjusting the boiler temperature itself can be the perfect solution.

To manage your boilers guarantee, repair and service information, use our free myVAILLANT web portal