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The untapped efficiency benefits of radiator balancing


David Kempster

Product Manager

Schneider Electric/Drayton

Dave explains the benefits of correct radiator balancing in achieving higher boiler efficiencies and reducing your heating bills.


Few of us appreciate the effect radiator balancing has on how much energy we use. If our radiators get hot, we are happy and believe everything is working as it should be. However correct radiator balancing is more than just ensuring an even distribution of heat around the radiators (although this is important). Correct balancing also performs an essential role in our boiler’s efficiency and how much we pay to heat our homes.

What is radiator balancing?

At a basic level, radiator balancing is a method of making sure that hot water reaches all the radiators in our heating system. Unbalanced systems can result in some radiators not heating up properly, so that parts of your home feel cooler. When this happens, it can prompt us to turn up our thermostat to compensate, but this can leave the rest of the house too warm and ultimately uses more energy.

At a more technical level, correct balancing has a direct effect on how efficiently a condensing boiler operates. Condensing boilers can achieve efficiencies of over 90% by recycling waste heat before it leaves the boiler. However, they need to operate at a lower temperature to do this, much lower than non-condensing boilers, otherwise efficiencies will be 75-85%.

A low ‘flow’ temperature out of the boiler is important, and we should aim for around 60degC, but even more important is a low ‘return’ temperature, i.e. the temperature of the water after it has travelled around your radiators. The lower the return temperature, the more efficiently the boiler operates. Correct balancing means that the return temperature is 20degC lower than the flow temperature, incorrect balancing can mean it is only 10degC lower, which makes a big difference to your boiler’s efficiency.

What are the key signs of an unbalanced system?

For basic balancing, i.e. achieving an even distribution of heat, the most common sign that your system isn’t balanced correctly is if the radiator closest to the boiler generates a lot of heat, whilst the radiator furthest away feels much cooler to touch. This is because the radiator closest to the boiler is receiving too much flow and the ones further away, not enough.

A more extreme example is where the radiators nearest the boiler take all the hot water from the boiler and return it directly to the boiler, effectively bypassing the radiators later in the system so they never get warm. Signs that your heating system is not balanced to achieve 20degC of difference between the flow and return temperatures are more difficult to detect. Some installers carry temperature clamps so they can measure the flow and return temperatures, but this ultimately requires getting someone to come to your home.

A DIY approach is to buy low-cost temperature sensors that clip to flow and return pipes and these will provide an indication of temperature balance. Other signs include the boiler cycling on and off a lot.

What causes an unbalanced system?

An unbalanced system can occur for several reasons. It may be that when your heating system was initially fitted this step was never carried out by the heating engineer, and so consequently has remained unbalanced since then. Alternatively, a system can lose its balance if your radiators have been removed for any reason, such as decorating, and then refitted.

Likewise, if you’ve ever had to replace an old radiator, this could have affected the balance of the whole heating system. Similarly, as TRVs open and close during the day, the pressure to each of the open valves will differ. This causes changes to the flow rate and affects radiator performance.

What are the benefits of balancing?

With the ongoing energy crisis and the need to try and reduce energy costs wherever possible, ensuring that your heating system is balanced is a cost-effective way of helping to reduce these bills. A balanced heating system is an efficient one, with research showing that an average 8.8% of energy waste can be saved by a fully balanced heating system, which is a significant saving in this current climate.

How do you balance a heating system?

Although balancing radiators may be seen as a time-consuming process by some engineers, product innovations such as auto-balancing TRVs have turned this complex process into a quick and permanent solution that helps reduce energy bills and ensures every room in your home is perfectly heated.

Auto-balancing TRVs are established products in the commercial heating market, but not available until recently for domestic systems. Drayton’s auto-balancing TRVs look almost identical to standard TRVs and they fit directly onto standard pipes without having to change anything.

For the householder they operate in exactly the same way. The difference is, unlike standard TRVS, they automatically adjust radiators according to pressure changes and maintain the correct flow to each radiator to keep the system permanently balanced. This ensures lower return flow temperatures to aid the boiler’s condensing process; improving boiler efficiency and saving you money.

How do I get some help?

Although you may be tempted to try and balance your heating system yourself, it is advisable to get a heating engineer in to ensure that the process is completed correctly. This can be done alongside other efficiency measures such as fitting a smart control and especially when changing the boiler. It is important to emphasise again that balancing is not just about every radiator getting hot, it is making sure the difference between the flow and return temperatures is as close to 20degC as possible.

Just note that whilst most heating engineers can get all your radiators hot, less are familiar with the benefits of 20degC balancing. You can direct them to the Drayton website for more help. Balancing radiators v bleeding radiator It is important to remember that balancing a radiator is an entirely different process with a different purpose to that of bleeding a radiator. Bleeding is intended to address issues with a single radiator which is not heating up evenly (or at all) because of air trapped inside.


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