Research providing information on the performance of a large collection of different heating systems present in the Future Homes test houses at the Energy House 2.0 facility at the University of Salford, has provided clear evidence that new homes heated by radiators have lower running costs than those heated by a combination of underfloor heating and radiators in the same building. This where a modern renewable heating system is the source of heat for heating and hot water in the home.
Application of heat pumps in new builds can lead to the default adoption of UFH downstairs with radiators upstairs. However, this latest evidence suggests that the use of radiators throughout a new property offers significant benefits where heat is provided by an air source heat pump rather than a traditional boiler.
The academics responsible for the research are Richard Fitton – Professor of Building Performance, Grant Henshaw – Energy House Research Assistant, William Swan – Professor, Phil Clark, David Farmer – Research Fellow, Anestis Sitmalidis and Xinyi Zhang.
The houses at the Energy House 2.0 facility were built by Bellway Homes and a partnership between Saint Gobain and Barratt developments. The report follows up on a report published in 2023 on the fabric performance of both of these homes.
The systems were selected, designed and installed by the housebuilders and their partners. The research team had no input on the design of these systems and were focussed only on the measurement of the performance of these systems, which number 28 in total, and covered a range of technologies including, infrared heat panels and air source heat pumps (floor mounted and roof mounted). Different heat emitter technologies were also tested including underfloor heating, skirting board heating and importantly for Stelrad, radiators.
All methods of heating the home were measured in the same chamber conditions reflecting typical (5 °C) and more extreme (-5 °C) winter temperatures found in the UK. This allows for a comparison between these technologies that up to this moment has not been possible and represents unique research.
Interestingly, systems with radiators throughout – on each floor – showed lower running costs than the systems with a combination of UFH and radiators. This was not focused on in the report but can be unambiguously calculated from data published within it.
Using the external ASHP with radiators throughout, the running cost was 11% less than with UFH. Using the loft ASHP with radiators throughout, the running cost was 13% less than with UFH. These outcomes are very revealing and highlight the running cost benefits of selecting radiators throughout a new home powered by an air source heat pump of any design.
Radiators throughout a home were shown to be consistently more cost effective than UFH and radiators combined when looking at the most realistic scenario i.e. a SAP intermittent heating pattern, at average winter temperatures. Out of all 28 tests carried out and researched, the most economic configuration was the external ASHP with radiators throughout running the SAP pattern in a 5 degrees C environment.
Analysis of other heating regimes tested indicated that if constant 24-hour heat is required then ground floor UFH has the lowest running costs. However, this is shown to be 25% to 35% more expensive than the standard SAP heating pattern with radiators throughout the home. In the overwhelming majority of homes, heating is targeted at times when it is required – not on 24 hours a day. Radiator based systems are clearly better suited to this. They are more responsive than UFH, more flexible and cost effective.
The ability to target heat is very simple with radiators via a locally mounted TRV. Temperature control is intuitive and simple. No external wiring, controls or configuration are required.
A popular function of heating controls is the one-hour boost. It’s a simple way of countering a cold snap or quickly raising the temperature outside of the normal occupational routine. It is also the ‘go to’ control method for those who find modern controls confusing or who are trying to control costs. Radiator based systems are the best solution in all of these cases.
Due to the high thermal mass and low response times of a UFH system, the user is committed to heating for longer periods, potential expensive repairs and restricted floor covering options. It is fundamentally suited to constant heating but in real world situations it lacks flexibility, and it is therefore less economical for the majority of households.
“This research confirms our understanding that radiators are the optimal choice when it comes to heating economically and flexibly,” says Tim Wells, Stelrad’s Engineering Manager. “It’s particularly reassuring that these results were achieved in an environment optimised for UFH. We can be confident that radiators are just as fit for the future as they have always been, whether the heat is provided by traditional means or renewable technology.”
To view the original technical report in full “Energy House 2.0 Study on Future Homes Standard Heating Systems” visit: https://salford-repository.worktribe.com/output/3397480/energy-house-20-study-on-future-homes-standard-heating-systems
