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What temperature should my boiler be set at for hot water UK?

  • Writer: paul millz
    paul millz
  • Apr 9
  • 3 min read

UK combi boiler temperature setting for hot water showing 55°C with steam from tap

When it comes to home comfort, one of the most frequently asked questions by UK homeowners is: “What temperature should my boiler be set at for hot water?” Setting your boiler to the right temperature can improve energy efficiency, reduce heating bills, and ensure your hot water is at a safe and comfortable level.


Let’s break down the ideal boiler settings, safety tips, and how to get the most out of your system.


Ideal Boiler Temperature for Hot Water

For combi boilers, the recommended temperature for hot water is typically between 50°C and 60°C. Most manufacturers and energy experts suggest setting your hot water to 55°C — a sweet spot that balances safety and energy efficiency.

  • Below 50°C? You risk water being too cool, encouraging bacterial growth such as legionella.

  • Above 60°C? You may waste energy and increase the risk of scalding.


Key Recommendation:

✅ Set your hot water temperature to 55°C for everyday use.



What About System or Conventional Boilers?

If you have a system or conventional boiler with a separate hot water cylinder, things work a bit differently. The cylinder thermostat should be set at 60°C to kill bacteria, but blended down with a thermostatic mixing valve at the tap to avoid scalding.


Why Getting the Right Temperature Matters

  • 🔒 Safety: Prevents the risk of burns or bacterial contamination.

  • 💷 Energy Efficiency: Reduces your gas usage and energy bills.

  • 🌍 Environment: Lower temperatures = lower carbon footprint.



Boiler Flow Temperature vs. Hot Water Temperature

It’s important not to confuse hot water temperature with boiler flow temperature. The flow temperature refers to the water used for central heating — not what comes out of your tap.

For efficient heating, especially with condensing boilers, aim for:

  • Flow temperature: 60°C

  • Return temperature: 50°C or lower

This allows the boiler to run in condensing mode, improving efficiency by up to 10%.


How to Adjust Your Boiler Hot Water Temperature

  1. Locate your boiler's control panel.

  2. Find the hot water temperature dial or setting.

  3. Set it between 50°C and 60°C (ideally 55°C).

  4. If unsure, refer to your boiler manual or consult a Gas Safe engineer.


Tips to Save Energy with Your Boiler

  • Turn down the flow temperature in warmer months.

  • Use a smart thermostat to control heating times.

  • Insulate your hot water cylinder if you have one.

  • Book an annual boiler service to keep it running efficiently.


Final Thoughts

So, what temperature should your boiler be set at for hot water in the UK? The answer is simple: around 55°C for combi boilers, and 60°C at the cylinder for conventional systems. This ensures safe, energy-efficient hot water without compromising on comfort.

Need help adjusting your boiler? Always contact a Gas Safe registered engineer.


FAQs

Q: Is 50°C hot enough for hot water?A: It’s the minimum safe limit. For better safety and hygiene, 55°C–60°C is recommended.

Q: Will lowering my hot water temperature save money?A: Yes! Lower settings reduce gas usage — just stay above 50°C for safety.

Q: Can I adjust the hot water temperature myself?A: Most modern boilers let you adjust it easily on the display. If unsure, check the manual or contact a professional.


Want more energy-saving tips and boiler advice?

Contact Paul at Plumb Rite for professional advice:


Tel: 01384 293044

 
 
 

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