Heat Pump Retrofit in London

The Greater London Authority (GLA) has commissioned a study from the Carbon Trust into the implications of a widespread uptake of heat pumps in London’s new developments, driven by the decarbonisation of the electricity grid.

Heat Pump Retrofit in London

You may not have time to read the full report published in August 2020, "Heat Pump Retrofit in London", which runs to 159 pages. The principal conclusions are summarised here:

  • Heat pumps are the primary technology choice for decarbonising heat in existing London buildings.
  • Heat pump technology is varied, versatile and can work in all London building types.
  • Heat pumps are not a like-for-like replacement for gas boilers or conventional electric heating and good practice system design is essential.
  • Improved energy efficiency in buildings is a pre-requisite for heat pump retrofit at scale and will require significant investment.
  • Flexibility of heat demand is essential for a net zero carbon energy system and can bring significant financial rewards at the individual building level.
  • Based on current gas and electricity prices, heat pumps will reduce fuel bills compared to conventional electric heating but could increase fuel bills compared to gas unless paired with energy efficiency, best practice system design and flexible use of heat.
  • The up-front cost of heat pumps is higher than traditional alternatives and many building types will require additional up-front financial support. However, the lifetime financial case for heat pump retrofit is already strong in some building types, such as electrically heated buildings, buildings with a high cooling demand and buildings that already require major renovations. These building types should be prioritised for heat pump retrofit.

The findings of this report highlight the urgent need for central government to provide a decisive regulatory and fiscal background to support the installation of heat pumps and energy efficiency at the scale necessary. To this end, we have included an action plan for scaling up energy efficiency and heat pump retrofit. The recommendations in the action plan are primarily for central government, but also include recommendations for the GLA and London Boroughs.

Wyndham Estate

Carbon Trust's Recommendations for Heat Pump Retrofit

The report's action plan for scaling up energy efficiency and heat pump retrofit includes recommendations to:

  • Rapidly escalate investment in thermal energy efficiency in buildings
  • Reduce the upfront capital cost of heat pumps paid by the building owner
  • Re-balance gas and electricity energy taxation to incentivise low carbon heating
  • Maximise financial rewards for the flexibility of heat demand
  • Catalyse the deployment of heat pumps in building types where there is already a strong financial case for heat pump retrofit, such as electrically heated buildings, buildings with high cooling demand and aging communal and district heating systems.

ICAX welcomes the Carbon Trust report and recommends you read this excellent "Heat Pump Retrofit in London" report in full.

ICAX welcomes the ambition of the GLA, and 22 of the London Boroughs, to achieve Net Zero by 2030 for council generated emissions.

ICAX is installing high temperature heat pumps in three communally heated housing estates in Southwark to take up the base load of heating in place of gas boilers.


See Ground Source Heating       See Ground Source Cooling      See Ground Source Energy


Ground Source Heat Pump Association