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HeatFlex UK

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Identifying the potential of AUTOMATED heat pumps as a flexibility resource

CNZ and Nesta, the UK’s innovation agency for social good, have partnered on a research project – HeatFlex UK – to improve our understanding of the potential of heat pumps as a flexibility asset.

Heat pumps are a relatively nascent technology in the UK, but ownership rates are growing. This trial seeks to identify an acceptable approach to remotely controlling heat pumps to unlock flexibility, which can support the grid during times of strain.

We want to better understand what ‘good’ automation of heat pumps looks like, in order to assess the amount of flexibility we can expect from these local carbon technologies in the future.  This knowledge is key to helping us design a more efficient future energy system that is trusted by consumers.  

Why is energy flexibility important?

In a future where we rely on renewables as a larger proportion of our energy mix, we can use the principle of shifting or reducing demand to support the intermittency of supply. Low carbon technologies (LCTs) such as heat pumps and electric vehicles will enable this energy flexibility.

Whilst their increased penetration requires greater flexibility, because of the increased amount of electricity we’ll need to use them, they have ‘controllable loads’. This means we can still adopt these technologies without putting the grid under strain, by using energy at different times.

Furthermore, we may be able to achieve comfort via heat pumps with lower energy consumption. This could mean that we need less overall investment in reinforcing or upgrading the electricity grid. Significantly, this can reduce the overall costs of the energy system and bring down bills for everyone.

Research overview

Right now, domestic flexibility is largely untapped. This is due to limited knowledge on consumer behaviour and challenges in the existing market and regulatory landscape. HeatFlex UK will:

Identify how we can use heat pumps as a flexibility asset to harness as much flexibility as possible from residential consumption. This is balanced against maintaining sufficient comfort and consumer satisfaction

Measure the magnitude of flexibility (kWh curtailed during time windows) that can be delivered by taking this approach

Test the level of household acceptance of automation to provide grid services and contribute to flexibility

Examine how flexibility capacity varies by household and property characteristics

Experimental heat pump trial

In winter 2022-23 we piloted a research method where we remotely controlled households’ heat pumps via a smart thermostat, to see if we can reduce or shift electricity demand and get feedback on whether their home was still at a comfortable temperature. These tests were ‘events-based’ and occurred over a set number of hours. 

Over the course of the pilot, we ran 20 events during which we successfully took remote control of our participants’ heat pumps and were able to “pre-heat” their homes before reducing their consumption until the end of the event.

Participants completed surveys so that we could gain behavioural insights about how their experiences during the pilot. To gain deeper insights, we conducted a number of interviews at different points in the trial. The electrical consumption and temperature for each property were also recorded across the entirety of the project. 


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heat flex

Want to find out more or get involved?

If you’d like to find out more about this trial, please drop us an email at

What phase is the research currently in?

Having completed the pilot phase, we are analysing the quantitative and qualitative data that we have gathered. This analysis should help us to assess how acceptable participants found the automation involved in each event and how much flexibility each household was able to provide. We intend to use the findings from the analysis to inform our design for the scaled up trial that we plan to conduct in the winter of 2023-24.

We’ll be implementing learnings from the pilot to scale up this field experiment to hundreds of consumers – or possibly thousands. The findings of these field experiments will then be used to create a scheduled plan to harness as much flexibility as possible during times when energy demand is very high. 

By scaling up the number of households who participate in this trial, we can better understand what ‘good’ automation looks like, how we can engender trust in automated low carbon technologies, and what this means for the amount of flexibility we can rely upon these assets to unlock in the future. 

By combining these insights, we hope that this research is one step on the journey to outputting an empirical metric that could be used to inform customers, aggregators and the grid about the opportunities to avoid home heating during peak time periods, thereby enabling a greener, flexible future energy system.