Does a Lower Boiler Temperature Increase Legionella Risk?
With the current cost of living crisis, many people have been carefully following the news about increasing gas and electricity prices since last year. Even though the UK Government has stepped in to help struggling consumers, energy prices are still far higher than they were two years ago, with the potential to rise even further.
Small wonder, then, that most people are looking to apply ways to bring down their energy bills. Whether that means going without heating for as long as possible or applying lots of smaller ways to make a difference to your monthly usage, you’re probably doing the same thing.
A version of this article asking whether lowering your boiler water temperatures to save money can increase the risks from legionella first appeared in Legionella Control International’s newsletter. To get it in your inbox, sign up for free here.
Can reducing central heating and hot water temperatures save money?
You may have read about dropping your central heating temperature by just a few degrees, for example. It’s a quick and easy way to make a difference without your home becoming too cold.
Another piece of advice we’ve seen concerns the hot water temperature rather than the thermostat for the central heating. They’re separate controls on a gas combi boiler. While it makes sense to drop the hot water temperature a little if it’s on full, you should be careful not to go too low. If you do, you run the risk of Legionella bacteria multiplying in your water system which is not a good scenario to encourage.
What is Legionella bacteria and is it dangerous?
Legionella bacteria is responsible for causing the potentially deadly Legionnaires’ disease, and the less serious Pontiac fever. With symptoms like those caused by ‘flu, it’s possible that some of those who contract the disease each year may not be aware of it. Common symptoms include a high temperature, muscle aches and pains, a fever, and a cough. If you are unlucky, these can progress to more serious symptoms that may require hospitalisation. Anyone who thinks they may have contracted Legionnaires’ disease should see their GP as soon as they can, who may request tests to determine whether this is the case.
Typically, simple home heating and hot water systems do not pose a risk of Legionella bacteria becoming an issue. They’re usually very small, simple water systems when compared to those found in office buildings, hotels, hospitals, and other large buildings that may have been added to or altered over the years. One of the biggest risks would lie in leaving a property empty for a few weeks, and allowing the water to stand, and so stagnate. Even then, thoroughly flushing through the water systems and outlets on your return would help to mitigate this risk.
Can you safely reduce your hot water temperature?
But now, with lots of people searching for ways to bring down their energy bills, turning down the hot water temperature seems to be another smart move. However, you must make sure the water temperature at the boiler remains above 60 degrees Celsius. The temperature of the hot water coming out of the taps should be 50 degrees Celsius and no lower (55 degrees Celsius in healthcare). This should ensure the risks from a build-up of Legionella bacteria in your home water systems are controlled.
Your best bet is to locate the manufacturers guide for your boiler and to read through it to get the instructions on how to set the boiler flow temperature for your heating. It should also provide instructions on setting the hot water temperature to ensure it does not drop below 60 degrees Celsius at the boiler.
Striking a balance between energy savings and safety
You can see how important it is to make sure you strike the right balance between saving money and staying safe. Many news reports are offering advice to help householders reduce their energy bills. Yet few have mentioned the potential risks from legionella if householders go too far with reductions in their hot water temperatures.
How to check your hot water temperatures for legionella?
Fortunately, it is easy enough to check the temperature of your hot water supply on your own. Get an accurate thermometer and run the hot tap. Ideally, it should be the one furthest from the boiler. Keep the thermometer in the water for one minute, then record the temperature. You need to make sure the water is 50 degrees Celsius or over (55 degrees Celsius in healthcare). If it is, you’re fine.
If you find the water temperature is lower than the 50 degrees Celsius target, just adjust the relevant boiler control to raise the hot water temperature. You can then check it again. This is a simple step to take, and anyone thinking of reducing the temperature of their hot water supply to save money should certainly do it. No one wants to ignore safety measures like this when they’re designed to help minimise the risk of legionella bacteria taking hold.
Reducing your energy bills while staying legionella safe
As many homeowners will undoubtedly be getting their boilers serviced before the cold weather hits, it might be wise to ask a professional boiler engineer to make sure your boiler is operating at the right temperature.
With the right settings, it is possible that homeowners could save between 6.4% and 8% on energy bills simply by adjusting the settings on their boiler. Yet with few sources online alerting people to the potential risks from legionella, it’s worth remembering that it’s important to strike a balance between energy conservation and safety.
Hopping online today to buy a thermometer could be the best purchase you make this year. We’ll all be looking to make savings wherever we can, but only within safe parameters.
Legionella and water safety specialists
Legionella Control Internationals expert teams of water safety specialists support business owners and those responsible for health and safety in the workplace. Our risk management solutions support duty holders, the responsible person and others with responsibility for the control of waterborne pathogens and other water safety risks, helping them to protect their staff, customers and others and so meet their responsibilities in this specialist area.
We deliver specialist Authorising Engineer (Water) services, legionella risk assessments, water testing, independent compliance auditing, City & Guilds training, expert witness support and other environmental risk management services that help keep people safe.
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