LOW CARBON SOLUTIONS
Installing the right size low-carbon heating solution with measurement
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Build Test Solutions managing director Luke Smith explains how heat loss measurement can help determine a home’s actual energy performance and size and specify a low-carbon heating solution before installation to ensure it performs as efficiently as possible
early 20% of total UK emissions are linked to heating buildings, according to research by the Government’s Business, Energy and Industrial Strategy
Committee, meaning we still have a significant task ahead to reduce the climate impact of our heating solutions. If the UK is to reach Net Zero by 2050, it needs to shift around 23 million homes from carbon- intensive fossil fuel-based heating to low-carbon heating solutions, as a matter of urgency. This problem is complex, as there is never a one-size-fits-all solution when it comes to low-carbon heating. Training, measurement and software innovations are needed to help identify the most suitable heating technology for a given situation. Incorrect energy usage estimates can mean a house is considered unsuitable for a specific low-carbon heating solution. This means residents can feel forced to stick with higher carbon output alternatives.
Inaccurate assessments of a home’s suitability for a heat pump or alternative low-carbon heating solutions are currently a significant barrier to wider adoption. This is where measurement comes in.
Measurement in practice
Build Test Solutions (BTS), Veritherm and Elmhurst Energy wanted to demonstrate how accurate home heat loss measurement could be a vital tool in understanding peak heat demand, while also supporting heat pump specification, sizing and system design. Together, they carried out a field trial of 56 UK homes with heat pumps installed, in line with BS EN12831 - the method for determining design heat load for heating systems in buildings. Heat load demonstrates the amount of cooling or heating needed in a building to maintain a constant temperature.
The MEASURED process:
All BS EN12831 calculations in the Measured study were carried out using the Heat Loss Calculator, a bespoke design from Elmhurst Energy, to create an accurate and realistic result. BTS and Veritherm measured the heat transfer coefficient of the homes, which is also directly compatible with BS EN12831. BTS carried out the testing over a three-week period while the home was occupied, which is a less disruptive process for residents. Veritherm carried out overnight testing in a vacated house. This involved a short period of heating, followed by a monitored cooling-down period.
The results:
The testing found that traditional BS EN12831 calculations only delivered an accurate assessment of heat loss 30% of the time. In fact, the majority of assessments (59%) created an overestimation. Moreover, a fifth of the measurements were incorrect by more than 50% against the presumed figures. This has huge implications for future adoption of heat pumps and consumer confidence in these solutions. Incorrect heat loss calculations can significantly impact the size or type of low-carbon heating solution residents are recommended, the eventual efficiency of the system, and the future carbon impact these properties could have. In a post-testing survey, residents also reported that the heat loss measurements didn’t cause significant disruption, which shows the limited impact these tests had on their daily lives.
The future of measurement
Undertaking a heat loss measurement before installation, using technology like Build Test Solutions’ SmartHTC, allows heating installers to make informed decisions based on measured data, rather than assumptions derived from visual inspections or estimates. SmartHTC can also measure the peak heat demand (kWp) of a property, confirming the suitability of a heat pump or alternative low-carbon heating system being installed.
Not only is it accurate, the measuring process is not onerous as it does not conduct a full room- by-room heat loss calculation. This can make it a useful tool to engage householders and educate them about the merits of insulation versus heating system size and cost.
Heating installers can blend heat loss measurement with their existing customer journey:
Step 1: Measure heat loss for three weeks during normal occupancy using SmartHTC sensors. Step 2: Use the data to educate the householder and to inform the design and size of a heating solution. Step 3: Provide a quotation and agree on a way forward. Step 4: Use the same measurement data to help heating engineers make more detailed and accurate designs. Step 5: Finalise the specification, purchase and installation. Step 6: Complete system commissioning, customer care and support.
The drive for more measurement and the deployment of low-carbon heating is quickly gaining momentum and heating installers need to be aware of it or risk falling behind.
Impacting regulations
Installers must also be aware of the regulations and guidance that are impacting the sector. The Future Homes and Building Standards Consultation, which completed in March 2024 and where results are expected in summer 2024, states that new builds are required to adopt high fabric standards, low-carbon heating and must be ‘zero carbon-ready’. The consultation also proposed housebuilders adopt measured energy performance on a voluntary basis to measure the as-built thermal performance of new homes versus design. The (Microgeneration Certification Scheme) MCS design standards require the need for room-by-room heat loss calculations to be conducted in accordance with BS12831. The latest version of the MCS-hosted calculator accepts the input of measured whole building heat loss, allowing for better calibration and checking of design models.
Some funding schemes, such as the Great British Insulation Scheme and ECO4, are also set to introduce a ‘pay for performance’ mechanism. Payments will be based on measured fabric performance, further helping to encourage more measurement and testing in the existing housing sector. This also stretches to social housing, which is seeing increasing levels of measurement and verification as a result of Social Housing Decarbonisation Fund requirements and PAS2035.
The heating industry is about to transition toward various low-carbon heating solutions. Capacity needs to be increased and measured heat loss is key to this process. Heating engineers can use measurement to optimise the customer journey and improve conversion rates and customer satisfaction. Meanwhile, new industry professionals can indirectly support installers with pipeline building, carrying out measurements and educating householders before passing them on to installers.
20 BUILDING SERVICES & ENVIRONMENTAL ENGINEER SEPTEMBER 2024
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