Installing A-rated TRVs are a cost-effective way for installers to reduce energy consumption and win more business, says Edward Morris, Technical Manager at Altecnic.

By now, most homeowners will be aware of thermostatic radiator valves (TRVs) and how they can be used to reduce their heating bills. But many don’t realise the scale of savings that are possible, and could be missing out. 

An Ecofys-Institute study found that efficiency improvements as high as 19% of the heating energy of a radiator can be achieved when replacing a manual radiator valve with a TRV. Taking this one step further, based on the average cost of an A-rated TRV, it would take no longer than two years on average for homeowners to reap the rewards of their investment. After that, any money saved goes straight into their own pocket.

When compared to other common heating energy-saving options, such as hydraulic balancing or installing a new system, thermostatic TRVs have the shortest payback period.

Not all TRVs are the same however, which is why in Europe the TELL classification scheme provides clear guidance to consumers via the thermostatic efficiency label.

The right to use ‘A-rated’ energy efficiency labelling can only be granted to products that fulfil the minimum requirements in line with EN 215, with adherence to influence of water temperature, hysteresis, response time, and differential pressure.

An opportunity for efficiency

The first and most obvious opportunity to improve a system’s efficiency is to replace manual radiator valves with A-rated TRVs. 

While there appears to be no figures for the number of such valves in the UK, a recent report from the European Building Automation Controls Association estimates that about 500 million uncontrolled valves are still mounted on radiators across the EU. If all of these were upgraded to TRVs, then EU citizens, including those in the UK, would save over £10 billion per year and reduce CO2 emissions by about 24 million tonnes. 

Obviously not all TRVs are the same, which is why the TELL rating system is so important. As you will know, TRVs work by sensing the air temperature around them and regulating the flow of water through the radiator to which they are fitted. It does this by using a sensor in the TRV head, which is filled with a material that expands as the room temperature rises and contracts when it drops.

The weight and density of the material used to fill this sensor affects the time it takes for the TRV to respond to a temperature change in a room. A liquid filling will expand and contract more quickly than a heavier material like wax, which is still used in some products. For the end-user, this means that a liquid-filled TRV offers a faster response time, for better comfort and improved energy savings.

A liquid-filled TRV is also less likely to deteriorate over time. The crystalline composition of wax means that it tends to get harder and heavier over time, with constant expansion and contraction. This affects its ongoing accuracy so, after a couple of years, consumers may find that they have to increase their temperature settings to achieve the same level of comfort, thus negating the energy savings that they could otherwise make.

Arguably, there is a case for replacing inferior TRVs with better versions, but with no hard and fast published figures you may be hard pushed to prove this. There are, however, other opportunities to fit new efficient TRVs.

For instance, anytime a new boiler is fitted, you could argue that the heating system should be upgraded if it is to achieve its full potential.

Indeed, the government-produced Domestic Building Services Compliance Guide suggests that “it is convenient and timely to fit thermostatic radiator valves when replacing a boiler”.

Potentially there is also a large TRV replacement market in the UK, because this technology has been around for at least a couple of decades.

Modern TRVs are more efficient than these older versions, but there is also a chance that if an existing system is older than 15 years, then it may have stopped working. Some homeowners may make the mistake of turning off the TRV for prolonged periods in the summer, during which time it could calcify or collect debris. This could cause the internal pin to seize and possibly the seal on the pin to break.

To conclude, not all TRVs are the same, so check that you are specifying and installing an A-rated TRV for maximum energy savings.

Awareness of the technology is high, but your customers may not realise that their older TRVs could be relatively inefficient and need replacing. It is a real win-win situation, where you can gain extra work and the customer will save money in the long term.