Profiling Energy Use in London’s Conservation Areas

Insights from University College London's 3D Stock Model

Significant information gaps exist in our understanding of the built environment in conservation areas. Common measures of energy performance, such as Energy Performance Certificate (EPC) ratings, create a narrative about the historic stock that often goes unchallenged. The lack of detailed evidence about the historic built environment prohibits data-backed contributions to the debate.

To help fill in some of these gaps, Historic England commissioned UCL's Energy Institute to apply their 3DStock model to London's conservation areas. This new approach provides new insights and a novel method to finding out more about the historic stock.

The 3DStock model is currently only available in London but will soon be available nationally. This study, therefore, contributes a demonstration of the types of heritage-led analyses that will be possible to achieve in the near future.

This greater understanding of the building stock within conversation areas and their composition, uses, and the occupants' energy use is important; helping us move closer to tackling our climate change objectives and filling important gaps in our database.

Taking stock

London has 1,056 conservation areas mapped and publicly available. An analysis of the stock within these areas shows:

Energy consumption and EPC’s in conservation areas and listed buildings

EPCs have some well-documented data limitations (as noted by UCL Energy Institute and Historic England). Nonetheless, mapping their application in London conservation areas is useful for information and descriptive purposes. The UCL 3D model successfully matched EPCs to 326,000 domestic premises in conservation areas. UCL analysed updated EPCs of 427,000 domestic premises in conservation areas, which is 60% of the total conservation area domestic stock, and 4,609 (54%) of the listed building domestic stock. Analysis by UCL concluded that there is no statistical relationship between non-domestic EPC ratings and energy use. Analysis of non-domestic EPC data is therefore excluded.

A smaller proportion of domestic buildings in conservation areas and listed buildings have EPC Band C and above

• There are proportionately more dwellings without EPCs in conservation areas and listed buildings
• The percentage of dwellings (with an EPC) with B and C grades is comparable to the rest of London, with conservation area buildings having 43%, listed buildings having 11%, and the rest of London having 44%
• Proportionally, there are more buildings in conservation areas and more listed buildings with EPC rating E when compared to the rest of London

Energy data shows domestic buildings in conservation areas use less energy per sqm

UCL investigated domestic energy intensities by postcode in conservation areas and in the rest of London.

• The results show that the energy used for electricity is the same between dwellings in conservation areas and dwellings in the rest of London (40 and 41 kWh/)
• Gas use is slightly lower in conservation areas compared to the rest of London (150 and 156 kWh/)

The percentage of dwellings with heat pumps is higher in listed buildings and conservation areas than elsewhere

• Domestic EPCs give data on the main forms of heating in dwellings, the majority of dwellings have gas as their main form of heating. However, the penetration of heat pumps is higher (0.6%) in listed buildings and in conservation areas (by floor area) than elsewhere (0.3%)

Solar energy installations in Conservation Areas and on Listed Buildings, although small, are being made at a higher rate than in the rest of the London stock

DECs and EPCs give information about buildings where solar PV or solar thermal collectors have been fitted to date. Figures show that 0.2% of buildings in conservation areas and 0.25% of listed buildings have undergone solar energy installation, compared to 0.16% for the rest of London

London’s historic stock has high solar potential

• The average roof area of buildings in conservation areas is 58, and of listed buildings is 93, compared with 49.5 for the rest of London. The amounts of electricity that can be produced annually per roof, assuming an average panel efficiency, are 6120 kWh (conservation areas), 9730 kWh (listed buildings), and 5340 kWh (London)

Historic offices show potential for energy efficiency

Display Energy Certificate (DEC) grades are based on actual metered gas and electricity use and give useful information on non-domestic buildings. There are relatively small numbers (around 3,000) of premises/ buildings with DECs in London.

• Analysis shows that there is a negligible difference between the energy use of offices in conservation areas and the rest of London (108 and 104 kWh/)
• A much lower figure of just 65 kWh/was found amongst a sample of 8 listed office buildings in London with a DEC. While a very small sample, this data nevertheless shows that listed properties, and their potential to conform to energy-saving targets, should not be neglected.

Conservation area and listed buildings are used for employment

Insight from the 3DStock model highlights the importance of historic buildings for employment:

• When looking at the mixture of activities, 10% of conservation area buildings have non-domestic use as the most dominant activity. In comparison, only 4% of the buildings in the rest of London are in non-domestic use predominantly. On the other hand, 19% of listed buildings are dominated by non-domestic activities
• 26% of the floorspace in conservation area buildings and 37% of the floorspace in listed buildings is currently in non-domestic use. In comparison, 24% of the floor space in the rest of London is in non-domestic use
• The predominant non-domestic activities in conservation areas and London as a whole, by count and by floor space, are offices and shops
• Conservation areas have proportionally more non-domestic buildings used as offices when compared to the rest of London. With 51% and 60% by count and floor space respectively, compared to 31% and 32% for floorspace in the rest of London
• Offices are even more predominant in listed buildings, with 88% of non-domestic listed buildings and 80% of non-domestic listed building floorspace being used as offices. This likely reflects the high concentration of older (and some newer) listed office buildings in the city and central London

Heritage forms the backbone of London’s local economies

The descriptive data from the UCL 3D model on the stock of buildings in conservation areas and listed buildings indicates just how important the historic environment is for employers and local economies.

The findings here corroborate the findings from Heritage Counts 2018 which focused on the commercial use of heritage in town and city centres and in conservation areas. The research also found that 26% of creative industries are in conservation areas, with a high concentration in London’s conservation areas.

The research found:

References

1. Liddiard, R., Godoy-Shimizu, D., Ruyssevelt, P., Steadman, P., Evans, S., Humphrey, D. and Azhari, R. (2021). 'Energy use intensities in London houses'. 'Buildings and Cities', 2(1), p.336. (Accessed: October 2024)