What Temperature Should Hot Water Be at the Tap UK?

James Elston
Written by James Elston
Updated on 17th May 2024
Posted on 16th May 2024
Topic: Boiler Advice
what temperature should hot water be at the tap and hot water cylinder

Is your hot water temperature leaving you lukewarm? Feeling the burn from scalding taps? You’re not alone.

hot water

Discovering the perfect balance for “what temperature should hot water be at the tap” can be a challenge.

Let our experts at Boiler Central guide you through the ideal hot water temperatures for safety, energy efficiency, and comfort, as well as how to maintain and troubleshoot your system for optimal performance.

Don’t let hot water woes dampen your day—dive in and find out how to strike the perfect balance!

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Tap Hot Water Temperature Overview

  • The optimal hot water temperature at the tap for safety, energy efficiency and comfort is recommended to be between 49°C and 65°C.
  • Regular hot water system maintenance, proper thermostat settings, and using mixing valves can ensure safety while maintaining desired temperatures.
  • Boiler or system faults should be promptly addressed with professional assistance to maintain safe hot water temperatures that prevent scalding & Legionella growth.

Ideal Hot Water Temperature at the Tap

The optimal hot water temperature at the tap balances safety, energy efficiency, and comfort. In the UK, the recommended temperature for hot water at the tap is between 49°C and 65°C.

This temperature range has been recommended for safety measures. This range helps to prevent scalding, inhibit the growth of Legionella bacteria, and minimise energy consumption, especially when hot water is stored in a tank.

See how to change your combi boiler flow temperature here in our guide

Safety Concerns

Hot water temperature must always prioritise safety. Two major safety concerns when setting hot water temperature are scalding risk and the growth of Legionella bacteria.

To avert the risk of scalding, particularly for vulnerable individuals such as children and the elderly, water temperatures should not exceed 44°C.

In contrast, to impede the growth of Legionella bacteria, which can cause Legionnaires’ disease, hot water should be maintained at a minimum temperature of 60°C in the cylinder.

Balancing efficiency, scalding risk, and Legionella prevention is vital when adjusting the hot water temperature at the tap.

Regularly checking the temperature of the hot water at the tap, in the cylinder, and in the shower and bath can help maintain a safe water temperature and ensure the comfort and well-being of everyone in your home.

Energy Efficiency

When setting hot water temperature, consider energy efficiency as a significant factor. Higher temperatures require more energy to heat the water, resulting in increased energy consumption and potentially higher bills.

On the other hand, lower temperatures can reduce energy waste and improve energy efficiency, especially when hot water is stored in a tank.

Setting the thermostat at a typical temperature of 60°C to 65°C can enhance energy efficiency.

In addition, reducing heat loss in the system and using modern, energy-efficient hot water systems, such as energy efficient boilers, solar powered boilers, and hybrid boilers, can further enhance energy efficiency and potentially lower energy bills.

Comfort Level

Although safety and energy efficiency are vital, individual comfort levels also have a noteworthy impact on determining the optimal hot water temperature. Although comfort varies from person to person, a temperature range of 40°C to 43°C is generally considered comfortable for most individuals.

As individuals age, their comfort levels with hot water temperature may vary. Most people, especially older individuals, may prefer warmer temperatures to achieve the same comfort level as younger individuals.

This is attributed to physiological changes that occur with age, such as a delayed core temperature onset threshold for sweating and a reduction in evaporative cooling.

Accommodating varying comfort levels requires balancing safety, energy efficiency, and personal preferences when adjusting the hot water temperature at the tap.

Controlling Hot Water Temperature

Controlling hot water temperature relies on the use of thermostats, mixing valves, and flow temperature adjustments. These components are instrumental in preserving an ideal balance of hot water temperature, thereby ensuring safety, energy efficiency, and comfort.

Let’s delve into the details of each method and how they contribute to controlling hot water temperature.

Thermostats

Thermostats control the temperature of hot water systems, contributing significantly to attaining a balance between safety, energy efficiency, and comfort. It is recommended to set thermostats in hot water systems between 60°C to 65°C.

A properly functioning thermostat monitors and controls the temperature of the water within the tank, ensuring the water temperature remains at the specified level set by the user.

Various types of central heating thermostats work in different ways are employed for boilers, such as stem thermostats, bulb thermostats, and electronic thermostats.

Regular maintenance and proper thermostat settings can help prevent issues such as inconsistent hot water temperature, water being too hot or too cold, and boiler or system faults that may compromise safety and comfort.

Mixing Valves

Mixing valves, especially thermostatic mixing valves (TMVs), play a key role in preserving safe hot water temperature.

They blend hot and cold water together at the outlet point to ensure that the water is delivered at a secure and consistent temperature. TMVs feature a temperature-sensitive element that precisely regulates the water temperature, deterring scalding and ensuring user safety.

By controlling the water temperature, mixing valves help to avoid burns and maintain a comfortable and safe bathing, showering, and hand-washing experience.

Regular maintenance and proper mixing valve settings can prevent issues such as inconsistent hot water temperature and water being too hot or too cold.

Boiler Settings

The temperature of hot water supplied to the tap can be controlled by adjusting boiler settings.

The boiler flow temperature setting and the hot water temperature setting can be adjusted to affect the temperature of the hot water. Incorrect boiler settings can cause inconsistent water temperatures, where the water may fluctuate between hot and cold during use.

Adjusting boiler settings may require professional assistance from a Gas Safe engineer to ensure the correct adjustments are made and to diagnose any potential faults in the system. Proper boiler settings can help:

  • Maintain consistent hot water temperature
  • Provide a comfortable user experience
  • Prevent scalding or discomfort caused by water being too hot or too cold.

Types of Hot Water Systems

There are various types of hot water systems available, each with its own advantages and disadvantages. The three main types of hot water systems are tankless or instant hot water systems, storage tank hot water systems, and heat pump hot water systems.

Understanding the differences between these systems can help you choose the most suitable option for your home and ensure the perfect balance between safety, energy efficiency, and comfort.

Combi Boilers – Tankless or Instant Hot Water Systems

Tankless or instant hot water systems also known as combi boilers provide hot water on demand, eliminating the need for a storage tank. These systems heat water directly as it passes through the unit, using electricity or gas to provide immediate access to hot water.

This on-demand heating can result in significant energy savings compared to traditional tank-style system boilers, saving between 8% to 34% more energy.

By providing hot water on demand, tankless systems can also allow for lower tap water temperatures, reducing the risk of scalding and Legionella bacteria growth.

However, the initial cost of installing a tankless hot water system may be higher compared to other systems, and factors such as the climate, energy prices, and the specific needs of the household should be considered when comparing the cost and performance of different hot water systems.

Read our guide on the best combi boilers here

Storage Tank Hot Water Systems

Storage tank hot water systems such as system boilers and conventional boilers store heated water for later use. Cold water is pumped into the tank, where it is heated by a gas burner or an immersion heater, and the heated water is then accessible for use throughout the residence.

Proper temperature settings are of utmost importance for these systems to prevent bacterial growth, such as Legionella, and maintain energy efficiency.

It is important to keep the hot water tank temperature within a certain range. The generally accepted range is 60°C to 65°C.

This range helps to prevent scalding, inhibit the growth of Legionella bacteria, and minimise energy consumption. Regular maintenance and proper temperature settings can help ensure the safety, energy efficiency, and comfort of storage tank hot water systems.

Read about the best system boilers for more information.

Best hot water tank temperature

Identifying the optimal hot water tank temperature is most improtant for safety, energy efficiency, and comfort. Earlier, we mentioned that a hot water tank temperature of between 60°C and 65°C is recommended. This temperature range is ideal for:

  • Preventing the growth of harmful organisms in the tank
  • Preventing scalding
  • Inhibiting the growth of Legionella bacteria
  • Minimising energy consumption, especially when hot water is stored in a tank.

Regular maintenance and achieving the right temperature settings can help ensure the safety, energy efficiency, and comfort of your hot water system.

Heat Pump Hot Water Systems

Heat pump hot water systems utilise heat from the air or ground to heat water, offering a more energy-efficient solution compared to other hot water systems. These systems use a refrigeration cycle to extract heat from the ambient air or ground and subsequently transfer it to the water contained in a storage tank.

Heat pump hot water systems are generally more cost-effective and energy-efficient compared to other types of hot water systems, resulting in lower energy bills and reduced carbon emissions.

However, the initial cost of installing a heat pump hot water system may be higher compared to other systems, and factors such as the climate, energy prices, and the specific needs of the household should be considered when comparing the cost and performance of different hot water systems.

Read more: Is a heat pump or boiler better?

Legionella Bacteria and Hot Water Temperature

Legionella bacteria, which can lead to severe pneumonia, thrive in water temperatures ranging from 20°C to 45°C. These bacteria are typically found in natural water sources, as well as specially designed water systems such as spa pools, evaporative condensers, cooling towers, and hot and cold water systems.

Maintaining a hot water temperature of 60°C to 65°C can help prevent Legionella growth, ensuring the safety and well-being of everyone in your home.

Ideal Temperature Range to Prevent Legionella

Maintaining a hot water temperature of 60°C to 65°C is key to inhibit the growth of Legionella bacteria. Legionella bacteria can survive and grow in water systems within a temperature range of 20 to 50 degrees Celsius, with optimal growth occurring between 32 and 42 degrees Celsius. However, temperatures above 50 degrees Celsius can obliterate most Legionella bacteria, effectively impeding their growth.

By maintaining hot water temperatures above 50 degrees Celsius, you can help prevent the growth of Legionella bacteria and ensure the safety and well-being of everyone in your home. Regular maintenance, proper temperature settings, and the use of mixing valves can further contribute to maintaining a safe water temperature and preventing the growth of Legionella bacteria.

Tips for Maintaining Safe Water Temperature

Preserving a safe water temperature is key to preventing scalding and restricting the growth of Legionella bacteria. Some tips for maintaining a safe water temperature include regular system maintenance, proper thermostat settings, and using mixing valves.

Regular boiler servicing can help ensure that the hot water system is operating efficiently and securely, avoiding issues such as inconsistent hot water temperature, water being too hot or too cold, and boiler or system faults. Proper thermostat settings can help prevent scalding and Legionella growth by maintaining the recommended temperature range of 60°C to 65°C.

Mixing valves blend hot and cold water to achieve the desired temperature at the taps, ensuring a safe and comfortable bathing, showering, and hand-washing experience. Choosing the right boiler for showers is also key too.

Common Hot Water Temperature Issues and Solutions

Typical hot water temperature issues encompass inconsistent hot water temperature, extremely hot or cold water, and boiler or system malfunctions. Addressing these issues may require adjusting the thermostat, mixing valve, or boiler settings, as well as seeking professional assistance from a Gas Safe engineer.

Identifying and rectifying these issues can guarantee the safety, energy efficiency, and comfort of your hot water system.

Inconsistent Hot Water Temperature

Faulty thermostats, mixing valves, or boiler settings can cause inconsistent hot water temperature. A malfunctioning thermostat can lead to irregular hot water temperature by not correctly regulating the temperature of the water.

Similarly, a malfunctioning mixing valve can produce varying water temperatures, causing discomfort and inconvenience.

To resolve inconsistent hot water temperature issues, you may need to adjust the thermostat, mixing valve, or boiler settings. If these adjustments do not resolve the issue, it may be necessary to seek professional assistance from a Gas Safe engineer to diagnose and repair any potential faults in the system.

Water Too Hot or Too Cold

Dealing with water that is too hot or too cold can be both frustrating and potentially risky. This problem can often be resolved by adjusting the thermostat, mixing valve, or boiler settings. For example, if the water is too hot, turning the thermostat or mixing valve down can help lower the temperature and reduce the risk of scalding.

If adjusting the thermostat, mixing valve, or boiler settings does not resolve the issue, it may be necessary to seek professional assistance from a Gas Safe engineer to diagnose and repair any potential faults in the system. Regular maintenance and proper temperature settings can help ensure the safety, energy efficiency, and comfort of your hot water system.

Boiler or System Faults

Boiler or system faults can cause a variety of hot water temperature issues, such as inconsistent hot water temperature or water being too hot or too cold. These faults may include a faulty thermostat, low water pressure, airlocks, a broken diverter valve, or a defective pump. In some cases, these issues may require professional assistance from a Gas Safe engineer to diagnose and repair.

By addressing boiler or system faults promptly, you can ensure the safety, energy efficiency, and comfort of your hot water system. Regular maintenance, proper temperature settings, and the use of mixing valves can further contribute to maintaining a safe water temperature and preventing issues related to boiler or system faults.

Summary

In conclusion, finding the perfect balance for hot water temperature at the tap is a critical aspect of ensuring safety, energy efficiency, and comfort in your home. By understanding the ideal hot water temperature range, the role of thermostats, mixing valves, and boiler settings, and the different types of hot water systems available, you can make informed decisions about your hot water system.

Regular maintenance and proper temperature settings can help prevent issues such as inconsistent hot water temperature, water being too hot or too cold, and boiler or system faults. With the right knowledge and tools, you can ensure the perfect hot water temperature and enjoy a safe and comfortable experience every time you turn on the tap.

Frequently Asked Questions

What temperature should hot water tap be UK?

For safety and efficiency, UK hot water tanks should be kept between 60°C to 65°C. Outlets distributing water from these tanks should provide a temperature of no higher than 50°C, with healthcare premises able to reach 55°C within one minute.

Is 50 degrees hot enough for hot water UK?

In the UK, 50°C is not hot enough for hot water as it increases the risk of bacteria such as Legionella developing. The ideal temperature of a hot water tank should range between 60°C to 65°C.

How hot is boiling water?

Boiling water is typically 212 degrees Fahrenheit, or 100 degrees Celsius, at sea level. This temperature may vary depending on the elevation.

How can I prevent scalding and Legionella bacteria growth in my hot water system?

To prevent scalding and Legionella bacteria growth in your hot water system, maintain a temperature of 60°C to 65°C and use thermostats, mixing valves, and proper boiler settings.

What are the differences between tankless, storage tank, and heat pump hot water systems?

Tankless hot water systems provide on-demand hot water, whereas storage tank systems store heated water for later use and heat pump systems use external sources of heat to heat water.

Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 16th May 2024
Topic: Boiler Advice

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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