Case Studies: Level 0 Pre-Apps

The following case studies are drawn from Level 0 pre-apps received as part of the Green Heritage Homes project.

• Phase 1 of the project was initially run as a Local Energy Advice Demonstrator (LEAD) project funded by the Department of Energy Security and Net Zero (DESNZ) from August 2023 to March 2025, led by Bath and West Community Energy (BWCE) with partners including us, Bath Preservation Trust, The Centre for Sustainable Energy, People Powered Retrofit, and the South West Net Zero Hub.
• Partnering with BWCE, Phase 2 of the project was launched in April 2025 for a 3-year period until 2028, and is funded by us along with Historic England, the West of England Mayoral Combined Authority (WECA), and Curo Group.

The case studies provide examples of different energy efficiency improvements, or retrofit measures, proposed to listed buildings which have been assessed by a Conservation Officer. The case studies include different building types, uses, and listing grades (e.g. Grade II, II*, I) to provide a range of examples which might apply to lots of buildings across the district. Case studies include buildings across Bath and North-East Somerset.

Case studies are categorised based on the types of retrofit measures discussed. Most case studies include more than one retrofit measure, and advice considers how measures may be used together.

Applicants have given consent for their pre-apps to be used anonymously to inform the following case studies. Please note this means that no identifying details can be provided relating to the site or the occupier, including images, addresses, or application reference numbers.

People who cannot access this document in its original format are entitled to receive it in an alternative format such as Easy Read, large print, translated language or an audio recording. It can also be emailed as a Microsoft document. Please contact alexandra_best@bathnes.gov.uk.

For more illustrated examples of listed building retrofit, Listed Building Energy Champion case studies will be made available on our website.

Expand the sections below to find out more.

Case studies: 2024 to 2025

Case study 1: Vacuum glazing, internal wall insulation, loft insulation, and air source heat pump (ASHP)

Proposed works to Grade II* terraced townhouse for installation of vacuum glazed sash windows, internal wall insulation in the top floor bedrooms, and an ASHP in the rear garden.

Read case study 1

Case study 2: Slim-profile double glazing, secondary glazing

Proposed works to Grade II semi-detached dwelling for upgrade of deteriorating cast iron casement windows with slim-profile double glazing or secondary glazing, and associated fabric repairs to windows and stonework.

Read case study 2

Case study 3: Slim-profile double glazing, vacuum glazing, secondary glazing

Proposed works to Grade II terraced townhouse to upgrade windows across the front elevation, including options such as slim-profile double glazing and vacuum glazing.

Read case study 3

Case study 4: Secondary glazing

Proposed works to lower ground floor flat in Grade I terraced building for installation of secondary glazing to windows in the front elevation.

Read case study 4

Case study 5: Secondary glazing, slim-profile double glazing, underfloor insulation, internal wall insulation, roof insulation, air source heat pump (ASHP)

Proposed works to Grade II community building for retrofit measures as part of future maintenance strategy, including draughtproofing of doors and chimneys, upgrades to existing metal-framed windows with secondary glazing or slim-profile double glazing, insulation of walls, floors, and roof, heating system improvements, and installation of an ASHP in the rear car park.

Read case study 5

Case study 6: Secondary glazing, slim-profile double glazing

Proposed works to Grade II mixed-use building for upgrade of windows in main building with secondary glazing, and upgrade of windows in rear 20th century extension with slim-profile double glazing.

Read case study 6

Case study 7: Secondary glazing, slim-profile double glazing, vacuum glazing

Proposed works to Grade II* detached mixed-use building to upgrade metal-framed casement windows, considering options including secondary glazing, slim-profile double glazing, and vacuum glazing.

Read case study 7

Case study 8: Secondary glazing, slim-profile double glazing, solar panels

Proposed works to Grade II terraced townhouse for upgrades to windows with secondary glazing, replacement of non-historic windows in rear elevation with slim-profile double glazing and installation of solar panels on rear roof slope.

Read case study 8

Case study 9: Secondary glazing, slim-profile double glazing, solar panels, air source heat pump (ASHP)

Proposed works to Grade II detached dwelling for upgrades to existing secondary glazing, replacement of non-historic windows and doors with slim-profile double glazing, installation of roof-mounted solar panels, and installation of an ASHP in the garden.

Read case study 9

Case study 10: Secondary glazing, slim-profile double glazing, vacuum glazing

Proposed works to first floor flat in Grade II terraced building for upgrade of street-facing windows, with options including improvements to existing secondary glazing, or replacement of sash windows with slim-profile double glazing or vacuum glazing.

Read case study 10

Case studies: 2025 to 2026

Case study 11: Secondary glazing, vacuum glazing

Proposed works to flat in Grade II terraced building for upgrade of existing windows and door with vacuum glazing or secondary glazing.

Read case study 11

Case study 12: Secondary glazing, heating upgrades

Proposed works to flat in Grade II terraced building for upgrades to existing heating system, installation of gas combi boiler, and installation of secondary glazing to improve performance of windows.

Read case study 12

Case study 13: Secondary glazing, heating upgrades

Proposed works to Grade II terraced office building for replacement of existing gas boiler and installation of an ASHP, and associated upgrades to building fabric.

Read case study 13

Case study 14: Slim-profile double glazing

Proposed works to Grade II terraced dwelling for replacement of metal-framed casement windows in rear elevation with slim-profile double glazing.

Read case study 14

Case study 15: Slim-profile double glazing, vacuum glazing, internal wall insulation

Proposed works to flat in Grade II terraced dwelling for replacement of existing single glazed sash windows with more energy efficient glazing, ventilation improvements, and options for internal wall insulation as part of re-plastering works.

Read case study 15

Case study 16: Loft insulation, secondary glazing, vacuum glazing, internal wall insulation, EV charging

Proposed works to Grade I terraced dwelling for replacement of existing single glazed sash windows with more energy efficient glazing, installation of EV charging point for on-street parking, loft insulation upgrades, and options for internal wall insulation in rear extension.

Read case study 16

Case study 17: Vacuum glazing, slim-profile double glazing

Proposed works to Grade II terraced dwelling for replacement of existing single glazed sash windows and rear French doors with more energy efficient glazing.

Read case study 17

Case study 18: Solar panels

Proposed works to Grade II detached theatre building for installation of roof-mounted solar panels.

Read case study 18