Historic Scotland Technical Paper 13: Embodied Energy Considerations for Historic Buildings

This report outlines the importance of life cycle analysis (LCA) in assessing the sustainability of new buildings and of maintaining, refurbishing and replacing existing buildings. Embodied energy and carbon is only one part of a building’s life cycle, but is of increasing significance.
The embodied energy and carbon, associated with building construction, is the energy required and carbon emitted to construct a building (including extraction of raw materials, manufacture of building products and construction of the building.) The other stages of a building’s full life cycle are operational energy and carbon (relating to the use of a building) and end-of-life energy and carbon (relating to its demolition and disposal).
This report, intending to support a discussion about energy and carbon assessment of existing buildings, provides an introduction to life cycle thinking generally, before presenting considerations specifically for existing buildings.
The report demonstrates that, although embodied energy and carbon is important generally, the energy used and carbon emitted in the past, i.e. the sunk embodied energy and carbon, does not matter in achieving the set UK reduction targets for greenhouse gas emissions. Sunk energy and carbon is of no relevance for mitigating the energy consumption and carbon emissions of today and the future.
Nevertheless, there is a strong argument for retaining existing buildings – even if their embodied energy and carbon is of no relevance today. The use of durable, long-lasting materials – as used in many older existing buildings – can reduce refurbishment cycles, therefore requiring less energy and carbon long-term. However, existing buildings need to be affordable to occupy and maintain, and energy-efficiency upgrades might be needed to achieve this. A LCA is required to choose the best long-term upgrade solutions. For this, the building’s construction type must be taken into account, as some upgrade options might be unsuitable for use in traditional buildings.
There will be an argument for replacing some existing buildings with new ones. However, this decision should not be taken lightly. A full LCA should be conducted for the replacement building and should include the end-of-life energy and carbon of the existing structure.
Decisions for energy-efficiency upgrades of existing buildings should be made on grounds of energy, carbon and financial costs, but other factors need to be considered, too. Historic buildings, for example, have a cultural and educational value, due to they can play a strong role in creating identity and have a significant economic impact for regeneration and tourism.
The sustainable use of existing buildings must be a national and global priority. Replacing a building has significant energy, carbon and financial cost implications. The retention of the existing building stock is, therefore, preferred, where its energy performance is good or can be improved to appropriate levels. Retaining existing buildings and seeking to enhance their energy performance in sensitive ways is in keeping with building conservation, sustainability and progress towards a low carbon society.