Caxton House – Phase 3

Decarbonisation • Heat pump • In progress


In this phase an electrically powered air source heat pump will be installed to substantially replace the gas boiler. CHCC will run a bivalent system in which the heat pump provides most of the heating and the gas boiler will be used as a top-up on very cold days. The situation will be monitored for a couple of years to optimise the heat pump’s performance and to determine when the gas boiler can be decommissioned.

Other energy efficiency work in this phase includes refurbishing the external fire doors funded by Caxton House’s own maintenance budget; and partnership work on securing funding from the Energy Redress Scheme, allowing PUNL to work with Caxton House to deliver additional sessions to local residents offering 1:1 advice and support and small energy saving measures including help with installation if required.

A lot of this work has been ongoing in parallel with phase 2. CHCC has appointed their heat pump supplier and purchased the unit. Subject to planning consent the plan is to install the heat pump in the summer of 2023.

Funding & delivery

The funding for the heat pump is substantially being provided by the Biffa Award with top- up funding from the Islington Community Energy Fund 6 and the London Community Energy Fund 6. PUNL has worked with CHCC on all these grant applications and on project management.

The need for planning was not clear at the start and we were operating under “permitted development” rules. Once the requirement for a planning application became clear then PUNL appointed Allford Hall Monaghan Morris, a local architectural practice to prepare the planning application. AHMM were supported by Hoare Lea, an engineering consultancy who prepared the detailed acoustic report. Both firms have provided this support pro bono and besides the financial savings to the project their professionalism and technical knowledge has been very valuable and has helped with the location and design of the heat pump system. The results from the noise survey meant that a noise attenuation unit is required so that noise levels from the heat pump will be within the decibel bands set by Islington Council.

Benefits & impact

The heat pump is due to deliver carbon savings of 16 tonnes a year which is equivalent to planting over 700 trees. The financial savings resulting from the energy savings will depend on how energy prices change over the next year, how building users respond to reduce energy waste and how the different heat pump and mechanical ventilation systems interact with each other through the next winter. PUNL will be gathering data and monitoring performance of the heat pump and MVHR systems alongside the suppliers.

A much bigger carbon saving is waiting to be delivered by replicating the learning from this project across the Octopus Community Network. The supply chain, financial model and business model ideas from this project have the potential to be carried over to other centres across the Network with support from PUNL and Islington Council and these conversations have started.