Known largely for their safeguarding properties, thermostatic mixing valves (TMVs) have become an essential and integral feature of modern plumbing systems. However, their other performance qualities are gaining recognition also, not least in terms of energy savings. Eric Winter, RWC’s EMEA Director of Product Development, explains how TMVs can contribute to a smarter, more cost-effective plumbing system.
As the world tackles climate change, the energy crisis, and rising concerns over public health and safety, we are all looking for technologies which really help to make a difference. As a well-known supermarket puts it, every little helps. So, cometh the hour, cometh the humble, but impactful thermostatic mixing valve (TMV). Now more than ever, it’s time to recognise its vital role in driving safety, savings, and sustainability into buildings across the UK.
The well-known safety factors
By mixing hot and cold water to deliver a consistent and pre-determined temperature, TMVs provide two vital safety functions – they help prevent scalding and, by allowing hot water systems to run at sufficiently high temperatures, they help protect against the buildup of Legionella bacteria in the pipework. For these reasons, TMVs are a necessity in all commercial and domestic new builds, properties undergoing a change of use, and in hospitals, care homes and other healthcare environments. In other words, pretty much everywhere, which is a real testament to their safeguarding capability.
There are two levels of certification – TMV2 (domestic and commercial) and TMV3 (healthcare). The performance difference between them is essentially the speed and accuracy of operation and the application they are used in. For example, while a TMV2 can serve multiple outlets such as sinks in a gym, TMV3 applications recommend one valve for each outlet. In most non-domestic buildings, TMV2s are tested annually, while TMV3s must be tested at least every 6 months after passing their initial test following installation.
Improved functionality, servicing, and performance
Because of their critical function, TMVs must comply with a broad range of regulations and British safety standards, including those specific to the NHS. The choice of valve clearly depends on the exact nature of the application, but RWC’s Reliance Valves comprises an extensive suite of TMV2 and TMV3 valves for every challenge, including Heatguard Dual TMV and Ausimix Compact or Ausimix Telescopic TMVs. Many have added value features such as isolators, test ports, and anti-tamper cap to improve functionality, servicing, and performance. All are fully compliant.
Making hot water go further
It’s for the reasons stated above that RWC’s TMVs are primarily known for their quality and safety. But the energy crisis and focus on climate change and sustainability has brought other features into focus – not least the need to save energy.
For gyms, healthcare settings, and multi-occupancy dwellings where large numbers of people are taking baths and showers, this is a particular concern. Research in the US suggests that hospitals typically use between 61 and 79% of their total energy on lighting, heating, and hot water. In the NHS, BMJ research suggests that most hospitals are
braced for huge rises in their energy bills and the uncertainty around energy costs rising indefinitely only adds further pressure on facility managers. To take just two examples, Nottingham University Hospitals NHS Trust is budgeting for a 200%+ increase in 2023, while Leeds Teaching Hospitals NHS Trust expects to be paying £2 million extra a month for electricity and gas combined. For a service that’s already under severe financial pressure, this is extremely worrying.
TMVs can be used to help reduce the burden, for example by installing a TBV or tempering valve, like the Masterguard, at the point of hot water generation. Allowing it to mix with the cold supply has a number of benefits. It allows water to be stored at high temperatures and then blended down to 55⁰C or 60⁰C as it enters the distribution system, increasing the amount of available hot water (compared with the tank capacity). Literally, making hot water go further.
Moreover, the addition of thermal balancing valves helps to maintain a constant temperature in the hot water system, which enhances the efficiency of TMVs. This means that larger buildings can maintain optimum output levels. At a time when people are looking to make even small additional savings, this potential to improve the control of hot water temperature can make a surprisingly big difference.
The renewable question
TMVs are designed to work best with water at a temperature of about 65 – 85°C, so one thing we’re often asked at RWC relates to whether they’re necessary or suitable for renewable systems is in combination with solar panels or heat pumps. Our answer is yes, both as a fail-safe mechanism, for added peace of mind, and for optimal efficiency. However, there are important things to bear in mind from a specification point of view.
With traditional gas boilers being slowly phased out, heat pumps are growing in popularity. And while they are an investment at first, they can reduce energy bills by over 20% compared to a new gas boiler, which over time will return the investment by means of lower energy bills. However, heat pumps run at much lower temperatures than conventional boilers, and special attention needs to be paid when specifying TMVs to be used in combination with a heat pump.
Similarly, when specifying TMVs in combination with the use of solar panels, it is important to remember that renewable energy resources run at much higher temperatures than conventional energy resources, often reaching 90°C. TMVs specified alongside solar panels will need to be able to withstand these extreme temperatures without compromising their functionality. As each project is unique, as a manufacturer, we would always recommend reaching out to our technical team to find the right TMV for the application in question.
Of course, to optimise efficiency it’s necessary to match the right valve with the application. On one hand, under-sizing can lead to pressure drops, starved outlets and inefficient flow. On the other, over specification can produce unnecessarily high flow rates, leading to water waste (and unwanted noise) if there are fewer outlets than the valve is designed to serve. To ensure the right application, simply check the technical data, or – in RWC’s case – the tech team is always on hand with expert support.
Sufficient hot water – sustainably
TMVs were initially developed to help enhance system and personal safety, but their capabilities extend beyond simply that. They have value in terms of efficiency and energy
saving. These qualities can be amplified even further by combining them with other valves to deliver sufficient hot water, sustainably.
They may not be the sole answer to the pressing climate and energy crises we’re facing, but as part of any forward-thinking plumbing system, they’re definitely part of the solution.
For more information about RWC and the Reliance Valves range of TMVs and TBVs, please visit reliancevalves.com
