Steve Sutton, Technical Manager at the Heating and Hotwater Industry Council, explains the importance of system balancing when designing and commissioning a heating system.
When it comes to ensuring that domestic heating is as energy efficient as possible, there can be a temptation to focus solely on research into the future of heat. However, there are some relatively straightforward adjustments that can be made to existing systems that will have a tangible effect on the effectiveness of home heating. One of these is to make sure heating systems are correctly balanced, a matter of best practice that Boiler Plus highlighted in interviews with heating engineers two years ago, and one which remains as important as ever.
Domestic heating systems need to be balanced to supply an equal flow of hot water to each radiator throughout the house, in order to maintain comfort and ensure the system works efficiently.
In properties that have large pipe runs, it is often the case that the radiator at the end of the system will not receive a very good flow of hot water. Similarly, convection means that some houses have radiators that are overly hot upstairs and lukewarm downstairs.
Heating systems can also become unbalanced as a result of changing the radiators. It may be that more have been added or removed during a home refurb and not appropriately rebalanced when refitted.
The problem with an unbalanced system is that heat will not be distributed evenly across heat emitters, essentially leaving some radiators cold while others become piping hot. This can result in some areas of the house not receiving heat, with obvious implications for the comfort of the occupiers.
Thermostatic radiator valves (TRVs) with too much flow may not operate properly. This could result in loud water ‘streaming’ noises as it flows through the valves, particularly as they start to close when the room temperature increases.
More pertinently, if consumers are unaware that system imbalance is the cause of radiators not working, they may simply turn up the boiler to mitigate the issue. However, this doesn’t address the root cause, and will lead to much higher energy bills and an inefficient heating system.
Once system imbalance has been identified as the issue, the solution is fairly straightforward. Radiator valves can be manually adjusted by ensuring that the correct flow rate is achieved across all heat emitters in the property.
Many of the latest TRVs include a product which facilitates adjustment of the flow rate through the TRV itself, which allows heating engineers to easily set the heat output of a radiator. Adjusting the flow of hot water through the TRV helps ensure correct heat output of the radiator, which the heating engineer will determine for each room based on heat loss calculations. TRV manufacturers provide a table that gives settings on the valve and output that will be received by the radiator.
This is where heat loss calculations are critical, especially for low temperature systems, as they help to provide a specific guideline for how the system should be balanced. Identifying where thermal energy is lost in the home enables heating engineers to mitigate through system balance, utilising the latest TRV technology to ensure consistent heat and efficiency throughout the property.
Ensuring that TRVs are fitted on radiators should be part of a heating engineer’s normal routine, with boiler replacements the perfect time to do so owing to the system already being drained down. Adopting this type of approach allows existing systems to work at maximum efficiency, ultimately maintaining the correct level of comfort for consumers while saving energy.
The rise of smart home technology should also be taken note of, with a range of companies now offering homeowners the ability to digitally ‘zone’ heating within houses. This has a natural fit with the use of TRVs, with many devices that are already fitted able to be upgraded to work as part of the smart home system. It should be noted, however, that for this to work effectively, systems will still need to be balanced.
The domestic heating industry is constantly working towards improving the efficiency and effectiveness of delivery into homes, and while this often involves a focus on the development of new appliances and fuel, the optimisation of existing systems should not be ignored. Indeed, given that the government is likely to introduce low temperature heating systems into newbuilds as part of SAP 10, this approach to balancing heating systems will become more important than ever.
In light of the ongoing coronavirus crisis, some of you may not be able to receive your copy of HVP magazine. If you’d like to change your delivery address, please contact our subscriptions department at email@example.com
Read a digital edition