Learnings

Outcomes

The project explored alternative options to support heating decarbonisation through electrification (ZEBs) given that heat pumps and heat networks may not be a suitable solution for ~20-25% of homes in the UK. This is often due to space constraints, geographic suitability for a heat network, cost, and the ease of installation. Innovative pricing structures (type of use tariff) were trialled to explore the cost competitiveness with traditional heating, while testing the performance of the system when paired with other LCTs helped the project to further develop confidence in the solution.  
The project installed the ZEB system in 30 homes and completed monitoring throughout the trial for 28 homes. The ZEBs performed as a suitable replacement for oil and gas boilers for trial participants, with all surveyed participants indicating that they would recommend the solution. The optimised charging of the ZEBs was also successful as the systems were able to draw >95% of their electricity outside of the four most expensive price periods within the energy price curve.  
Key findings include:  
Customer interest in the ZEB was high - with over 2,000 sign ups across the UK. In many cases, the ZEB was being considered as an alternative to a heat pump, where the latter may not have been suitable or the preferred option by the customer 
Installations were quick and non-disruptive, taking 1-2 days on average throughout the project 
The experience of heating was unchanged with a ZEB vs a fossil fuel system, with no major issues raised regarding the experience of heating by the project participants 
All participants interviewed would recommend a ZEB, with stronger support from customers with low heat demand and lowest running costs 
Some constraints in the project led to issues with customers’ understanding of ZEB charging patterns, running cost and overall control of the system. During the project, participants had to leave automatic charging enabled at all times, preventing direct intervention. This was an unavoidable restriction for the project only, but highlights the importance of providing user control, even over largely automated systems 
Separation/decoupling of electricity consumption and heating provision was a huge success. ZEBs were able to draw >95% of the electricity required outside of the four most expensive price periods within the energy price curve. This shows how ZEBs can be highly flexible in their power consumption in response to market signals 
Even in winter conditions, where 67% of the heating demand fell during the most expensive system price periods (morning & evening), the ZEBs drew <10% of their total power requirement at peak times 
The project also highlighted the headroom available for DSO & ESO signals to complement energy price signals. Doing so can help avoid herding and spread electricity consumption across similarly-priced periods to alleviate network congestion and optimally utilise network capacity 
There is far more to be investigated on the role thermal storage can play in the transition to Net Zero. NeatHeat shows the huge potential for technologies like the ZEB to provide network flexibility services, system balancing and delivering user comfort with a familiar heating experience. We have also identified new sources of potential value such as: using behind-the-meter data to support network monitoring; and using the ZEB as an option for distressed/emergency purchase (a scenario other low carbon solutions struggle to solve). 
It is also clear that policy change is required to make these technologies more accessible and compelling to homeowners. Running costs, given the price of electricity vs fossil fuels, are still a barrier/concern for many customers and the lack of policy support for thermal storage (VAT relief and access to the Boiler Upgrade Scheme in particular) means that customers who cannot get a heat pump are left covering the full cost of installing an alternative. For thermal storage to become a widely adopted solution, policy changes are needed alongside improvements in technology, tariffs, customer proposition and awareness. 

Lessons Learnt

The trial results show that ZEBs are a promising option for heating decarbonisation, especially in homes with limited space for heat pumps. Participants were satisfied with the solution, and its charging optimisation effectively reduced network load during peak times.  
 
The project identified several key areas for improvement some, which are discussed below (a full list can be found in the final reporting for the project):  
Customer understanding of existing heating systems is limited – understandably, many people do not know if their system is regular or system, combi or conventional boiler. tepeo pivoted early in the project eligibility assessments to simply ask whether customers had a hot water tank as this is naturally more widely known 
Customers are often planning other heating/hot water upgrades – when installing a new heating system, particularly low carbon options like the ZEB or heat pumps, customers consider their controls, hot water solution and radiators. In general, less disruption is preferable, but customers understand there can be benefits to upgrading various parts of their home/heating system if this is affordable. One of the benefits of the ZEB is that these changes do not need to happen at the outset, allowing customers to phase upgrade and achieve lower running costs over time 
ZEB understanding & confidence – the ZEB is a new product, which operates in a familiar way in terms of heating (thermostat, programmer, boiler responds and delivers heating to radiators), but the charging side of how a thermal store works was new to all customers in the trial. Coming out of winter into mild weather and summer, customers needed support in their understanding of how the ZEB would respond, and whether and how to use additional features such as an away mode which disables smart charging while customers are away of prologued periods of time . Using smart charging to automatically optimise heating in the home simultaneously reduced the need for customers to micro-manage their ZEB but could create a sense of uncertainty about when and how much their boiler would charge. As part of the learnings from this project, and other smart charging customers, tepeo are investigating how to display planned charging to customers. This will allow them to better understand what the ZEB intends to do, intervene if they disagree, and improve the overall confidence in automatic charging based on the energy system need. We believe this will be crucial for mass market adoption of any automatically scheduled devices (EV chargers, home batteries, hot water stores etc). Customers may agree with the schedules calculated by automated, intelligent systems, but may expect greater transparency than the ZEB provides today 
Knowledge of heating systems – this was low across the customers that participated in the trial. With a new product type, there is also a learning curve on how different parts of the heating system work – particularly for customers who have installed other technologies at the same time (thermal store, new heating controls e.g. smart thermostats). For users of new systems to have a positive experience, from which they can become advocates of LCTs and support the wider adoption across the country (word-of-mouth marketing & norm-forming), installers, energy suppliers and manufacturers will need to develop clear and concise educational materials which build user understanding over time. If it is possible to design-out the need for in-depth user understanding, this is generally preferable 
Heating requirements & user preferences – personal attitudes, household/family dynamics and heating system configuration created a wide range of expectations and preferences for heat provision. Within the NeatHeat project, there were a range of preferences. Broadly these can be divided into cost-focus vs comfort-focus. Some customers wanted the ZEB to optimise for the lowest running cost possible, even if this runs the risk of poor/compromised heating performance e.g. a ZEB that charges to the minimum expected heat demand and may not have a reserve of low-cost energy available if user demand or weather changes result in greater-than predicted heat demand. Other customers prioritised comfort above running cost, preferring their ZEB to maintain a float or reserve charge level to cover variability, unpredicted heat demand or just to ensure the fastest possible reheat time from a ZEB at a higher state-of-charge (heating output is greatest at higher states of charge)