Making sense of TRVs

Making sense of TRVs

Although the energy saving benefits of TRVs have been well documented in recent years, the type of TRV you choose to install could make a big difference to these benefits, says Bjorn Sejr Nielsen, Marketing Director of Danfoss.

Cut heating costs
Effective and easy to install, the modern thermostatic radiator thermostat, commonly know as a TRV, enables end-users to control the temperature of individual rooms in their home. Fitting a TRV on every radiator prevents the unnecessary – and expensive – overheating of empty rooms, whilst ensuring that occupied rooms are comfortably warm. Having this level of control can really help households reduce their heating bills and their carbon emissions. And it’s not just TRV manufacturers’ who are making these claims. Tests carried out for BEAMA Heating Controls group in the Energy House at the University of Salford showed that the installation of effective temperature controls on home heating systems has a far more significant effect on minimising energy use than previously predicted. In addition, the research findings found that the application of TRVs was essential to optimising energy savings, even if the system is balanced, by providing satisfactory heat distribution throughout a dwelling.

Informed choice
So, we have established that TRVs can play a pivotal role in keeping homes comfortably and, perhaps most importantly, affordably warm. The question is, how do you go about choosing the right TRV for your customer from the wide range of products on the market? When faced with a number of models offering different functions, features and sensors, you can’t blame busy installers for simply picking the product they’ve always used and are familiar with fitting. However, knowing the main differences between the various types of TRV, particularly the material used in the sensor, will help installers make a more informed choice – and help them avoid potentially costly call-backs if the TRVs don’t perform as promised.

What is a TRV?
As every professional heating installer 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 means of 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 the sensor has a direct impact on the time it takes for the TRV to respond to a temperature change in a room. According to basic scientific principles, a lighter liquid filling will expand and contract more quickly than a heavier material like wax, which is used in some products. Needless to say, a TRV that offers a faster response time means improved comfort and energy savings for end-users.

Liquid-filled TRVs
As well as offering greater accuracy and efficiency, the liquid used in a TRV sensor is less likely to deteriorate over time. It doesn’t have the crystalline composition of wax, for example, that tends to get harder and heavier with constant expansion and contraction, causing a detrimental effect on the TRV’s accuracy and performance. It may take a year or so, but as this change occurs consumers with wax-filled TRVs may find they have to keep increasing their temperature settings in order to achieve the same level of comfort. In having to do this they could wipe out all the energy savings they were making when they first installed this type of TRV.

Consistent performance
At Danfoss, we feel strongly that under-performing products could easily undo the progress the UK heating industry has made in raising awareness of the TRV as a simple yet highly effective heating control. From our extensive experience in this market, liquid-filled sensors will deliver more consistent performance over the life of the product – and that has to be a major selling point for end-users and installers alike.

False economy
Although the case for choosing TRVs with liquid-filled sensors may seem unequivocal, there are a few other factors installers should bear in mind before making a purchase Achieving longer lasting performance and durability will still depend, to a degree, on the robust construction and quality of the TRV itself. As the old saying goes, you get what you pay for. Opting for a TRV that uses lower quality components could lead to problems further down the line, such as liquid leaking from the sensor, resulting in a false economy for installers and their customers.

Improved profitability
Taking the time to find out a bit more about the TRVs they fit on a regular basis could make life easier for heating installers, make their business more profitable and increase customer satisfaction. To get further details about the different products currently available, simply check out the manufacturers’ websites or ask advice at the trade counter the next time you buy TRVs. For more information visit