As the UK transitions to low-carbon heating, heat pumps are becoming increasingly common in homes. As well as being efficient and environmentally friendly, they also have another, less-visible role to play. Connected heat pumps can actively help balance the grid.
If demand rises quickly, or renewable generation drops unexpectedly, the system operator needs ways to respond. The old answer was simple: burn more fossil fuels to increase generation., The new one is smarter: reduce demand through flexibility, by harnessing thousands of domestic assets like heat pumps.
It starts with a control signal. It might be sent directly by a system operator or triggered through price signals in the market. Either way, it indicates that the system would benefit if certain devices adjusted their behaviour for a short period of time.
For a heat pump, this doesn’t mean switching off. Instead, the response can be more subtle and carefully managed.
Imagine a typical winter evening. Demand is high as people return home, cook dinner and turn on the heating. At the same time, renewable generation might be lower. The system is under pressure, and a signal is sent to reduce demand.
If a home has a connected heat pump, it may respond in different ways. It might reduce its output slightly for a short period. Or it may have already pre-heated the home earlier in the day, when electricity was cheaper and more abundant, allowing it to pause later without affecting comfort.
This idea of pre-heating is central to how heat pumps provide flexibility. This works because buildings themselves can store heat. A well-insulated home doesn’t cool down immediately, giving the system time to reduce demand without the occupant noticing any difference.
Behind the scenes, this process is coordinated digitally. Heat pumps are connected to control platforms, often run by energy suppliers or aggregators. These platforms receive signals, either from the system operator or energy markets, and decide how individual devices should respond.
Importantly, these decisions consider more than just the grid. They account for indoor temperature, user preferences and weather forecasts. The aim is to support the system while maintaining comfort.
In some cases, households benefit financially too. Research suggests that using heat pumps flexibly could lead to meaningful savings, with one study estimating hundreds of pounds per year in reduced energy costs.
When these small adjustments are repeated across thousands of homes, the impact becomes significant. A slight reduction in demand in each property adds up, helping the system avoid more expensive or carbon-intensive interventions.
There is growing evidence that this works in practice.
Analysis from Energy Systems Catapult’s Living Lab shows that households with heat pumps are already taking advantage of cheaper off-peak electricity tariffs — warming their homes and heating their water when energy costs less. This points to a real opportunity for heat pumps to reduce pressure on the electricity grid by shifting when they use power.
Meanwhile, our latest Innovating to Net Zero report shows that flexible operation can smooth peak demand and better utilise renewables.
However, scaling this approach across the country is not straightforward. It depends on local network constraints, reliable technology, clear incentives and trust from consumers.
This is the focus of projects such as GridFlex, a UK initiative led by Energy Systems Catapult in partnership with Digital Catapult. The GridFlex programme is exploring the technological and market enablers that will allow digital innovation to unlock flexibility more effectively and at scale, building frameworks and networks that support long-term growth in the flexibility ecosystem.
People need confidence that their heating will remain comfortable and under their control. At the same time, systems must be robust enough to operate automatically and securely.
This is why heat pumps are more than just a replacement for gas boilers. They are part of a wider, interconnected system where homes, markets and infrastructure all work together.
What might seem like a small adjustment in one home is part of a much bigger shift. A system where everyday technologies quietly respond to signals in the background help to keep the lights on while building a cleaner, more flexible energy future.
If you’re interested in how technologies like heat pumps can support the energy system, and how innovators are developing these solutions, you can find out more about the GridFlex programme here: https://www.digicatapult.org.uk/programmes/programme/gridflex/
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