Net Zero Heating of Heritage Public Buildings
Alton Town Council, in partnership with the Greater South East Net Zero Hub, is seeking solutions to achieve Net Zero heating for a Grade II listed building. The building presents challenges, including limited space for heating systems, poor thermal performance, and large internal spaces. These solutions will be directly applicable to Alton Town Hall and will help guide the approach for a wide range of similar local authority assets, as well as potentially informing strategies for other national heritage buildings.
Opportunity
Challenge opens
28/04/2025
Challenge closes
29/05/2025
Benefit
Alton Town Council, in collaboration with the Greater South East Net Zero Hub, is seeking innovative technologies to address the challenge of efficiently heating Alton Town Hall and similar heritage buildings. These buildings face multiple constraints that make straightforward solutions, such as external air source heat pumps and large emitters, unsuitable
Background
Alton Town Council are committed to meeting their commitment of Net Zero operations by 2030.
Greater South East Net Zero Hub (GSENZH) support local authorities and Historic England on their transformation to net zero. Many buildings owned by local authorities across England hold listed status, which presents unique challenges to achieving net zero goals.
Alton Town Hall, originally constructed in 1871 as a fire station, has since been converted into council offices and a council chamber on the top floor, with rentable spaces on the ground floor, including small businesses and shops. The buildings current challengeis upgrading its fossil fuel-based heating systems to meet Net Zero targets while maintaining its heritage integrity.
Building overview:
Located in the central square of Alton,all sides are bound by public spaces.
Construction is typical of the era;
Structure - solid brick walls (one brick thick) withdressed stone, high- plaster finishes, and large, single glazed sash windows.
The roof- slate tiles supported by a king post timber trusses, purlins, and rafters, with a small clock towerfeaturing two louvered sides for ventilation. The clock tower sits over a small, concealedleaded flatroof.
Internally - there are rich period decorations, high ceilings, and internal walls approximately 250mm thick, constructed with lath and plaster timber studwork.
Current energy performance:
Main heating fuel – Natural Gas
Total useful floor area 173 square metres
Electricity used - 9420 kW h
Gas used - 35903 kW h
Total Carbon Dioxide (CO2) emissions (tonnes per year)
Electricity = 5
Heating = 7
Renewables = 0
Current heating and fabric improvements:
Loft insulation (cold roof) and draft sealing doors and windows have been completed. Some of the lower floor rooms have been modernised with insulation and electric heating, as they are rented to other users.
Secondary glazing and thermal blinds are planned for installation in 2025, as upgrading the windows to double glazing is prohibited due to conservation requirements.
The lobby, stairwell and first floor are heated by a compact wall-mounted gas boiler with a low- temperature hot water (LTHW) system. This system runs a combination of period cast-iron radiators in the council chamber and public spaces and modern steel radiators in the office areas.The boiler, locatednear the main entrance with a balanced flue to the square, is 15 years old and scheduled for replacement in 2026.
Domestic hot water is provided by point of use heaters.Electric metres and main panels are alsolocated in the lobby next to the front door in the lobby.
Most of the building’s ground floor comprises three let units. These spaces are more modern, with double-glazed windows and simple electric convection wall heaters.?Heating upgrades for these units are nota specific part of this challenge.
This challenge is brought to you by:
