What temperature should you set your boiler in winter?

Many households can benefit from changing the boiler's temperature in winter, helping maintain comfort and energy efficiency.

Here is some advice on what boiler temperature you should choose for the colder months and how to adjust your boiler.

EASY AS HACK 

Whatever type of boiler you have, it’s best to check the manual to understand where the temperature controls are and how to use them. The manual might also tell you what temperature to set your boiler in winter.

what does the temperature of your boiler mean?

First, it’s essential to be clear that we’re talking about the temperature your boiler heats your water to before it gets sent to your radiators – not the temperature you set on your room thermostats or thermostatic radiator valves, which determines when your heating kicks in or turns off.

Whatever boiler you have – the most common types are conventional and combination, or combi. It needs to be set at a specific temperature, often called the flow temperature to heat the rest of your home.

what temperature should my boiler be set at?

When the colder months of the year come around, getting the boiler temperature correct is crucial for maintaining the right balance between heating that is both comfortable and cost-efficient.

If you’re asking yourself what temperature I should set my boiler to in winter, there’s no universally agreed answer. However, as a general guideline, you should adjust the temperature of most conventional or combi boilers to between 60°C and 70°C ^[1] 

Choosing a setting within that range should mean you’ll have warm and cosy rooms. Still, factors such as the size of your home, insulation, and number of radiators make your place unique, so experiment to discover what suits you best.

Bear in mind that the higher you have set the flow temperature, the quicker your boiler will be able to heat your home, which is also likely  to mean your heating bills increase as a result.

how to set your boiler temperature?

To set your boiler’s flow temperature, it’s a good idea check the manual first(look online if you don’t have a paper version) and remind yourself of the controls. These are usually located on the front of the boiler; types of controls vary and can feature a dial or a digital display.

Before you change anything, take a photo or note how everything’s set currently, so you can refer back to it if needed.

If the controls are straightforward, it should just involve turning the dial up or down or pressing the + or - buttons to adjust the temperature. However, some dials don’t show the actual temperature and instead are numbered 1-6 or show a line of increasing thickness. As a guide, 60°C will usually be No. 3 or about halfway along the line.

considerations for different types of boilers

Depending on your boiler type, there are different considerations to be aware of when adjusting the temperature.

• A conventional boiler (with a hot water storage cylinder in an airing cupboard, utility room or loft) typically has a single control dial or digital display that regulates the flow temperature for both heating (radiators) and hot water to taps.
• A combi boiler (without a cylinder) usually has two dials/displays – one for heating (often with a little radiator icon over it) and one for hot water (with a little tap icon). This choice means that adjusting the heating temperaturedoesn’t affect the hot water temperature.
• Citizen’s Advice provides a simple video guide to setting the temperatures of conventional or combi boilers.

• High-efficiency condensing boilers use a heat exchanger to recover almost all the heat from the gas it burns. It doesn’t need to use as much fuel to heat your home, so if it is well-insulated, you can set the flow temperature as low as 45°
  
  

when is the best time to adjust your boiler temperature?

It’s up to you, but adjusting your boiler temperature before the cold really sets in is a good idea. Ideally, you should start using your heating system towards the end of October – or when indoor temperatures dip to what you think are uncomfortable levels.

However, there’s no definitive answer to when you should turn on your heating, prompting annual debates and disagreements in every household!

While some people want the radiators on as soon as summer fades, others might want to delay turning on the heating for as long as possible to save money on energy costs or to help the environment.

risks of a low boiler temperature during winter

If you set your boiler’s temperature too low, this risk is that some parts of your home aren’t warm enough, which might be uncomfortable for most but could also be hazardous for older people or those with health conditions.

If you have a conventional boiler system, the flow temperature affects the water in your storage cylinder and your radiators. A temperature below 65°C can increase the risk of legionella bacteria – a potentially fatal type of pneumonia – growing in the cylinder. Your cylinder will probably have its own thermostat fitted to it, so make sure it is set to at least 65°C.

efficient ways of heating your home

Your energy bills may increase slightly during winter if you increase the flow temperature of your boiler, but there are other ways to trim your energy bills, such as:

• Adjust your home’s central thermostat so that a lower overall temperature will prompt your radiators to come on. Just a 1° drop can impact your energy bills. Generally, anywhere between 19°-21° should be comfortable for most homes.
• Use a timer to turn the heating off when not in the house.
• Install thermostatic radiator valves to control when the heating comes on in individual rooms – for example, experts recommend that bedroom temperature be set to a lower value than the rest of your home to help people sleep.

FAQs 

what is the best temperature for a combi boiler?

The best temperature for a combi boiler is between 60 and 70°C.

will increasing your boiler temperature increase you bills?

Yes, increasing your boiler temperature may increase your bills.

can increasing my boiler temperature improve my boiler efficiency? 

No. Increasing boiler temperature may slightly decrease your boiler’s efficiency – however, keeping it between 60 and 70°C is ideal.

are boiler controls different to heating controls?

Yes, boiler controls are different to heating controls because while the latter is used to turn your heating on and off, the boiler changes the temperature in the water system.

is just before winter the best time to adjust your boiler temperature?

Yes, just before winter is the best time to adjust your boiler temperature for peak efficiency.

does boiler pressure drop during winter?

Yes, boiler pressure does drop during winter because of factors such as frozen pipes and increased demand on your heating system. With the heating on, your boiler pressure should be between 1.0 and 2.0 bar.

For more helpful household tips and advice, go to Solved.

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Sources 

[1] - Getting Your Boiler Winter Ready