Academicians and professionals in the architecture, engineering, and construction (AEC) field have expressed an increasing interest in sustainability and its application in the development of construction projects, especially with its deemed relationship with lean construction, for the purpose of improving efficiency in the construction processes. Practices framed under the lean philosophy show their potential in reducing environmental, economic, and social impacts during the construction phase, with an increase in the parameters of sustainability in the development of projects.

Around the world, engineers, architects and policymakers have been exploring ways to deliver highly efficient buildings whose reduced energy demand is satisfied by clean, renewable energy. Building off of the broader concept of a green or sustainable building, the concept of the “net zero building” focuses on the energy dynamics and performance of the building. And as policymakers and leaders align toward the net zero concept, the focus on achieving deep energy efficiency has centered on integrated technologies as well as ways to connect buildings to the natural environment.

This report is the first report of the ‘Energy Savings 2030’-project which seeks to help the Coalition for Energy Savings to produce a robust and timely input to the 2030 policy discussion. It brings together and summarises recent empirical evidence on costs and benefits of energy efficiency measures. The evidence gap in terms of reliable ex-post data is well known. In the majority of cases results from ex-ante modelling studies inform the debate. The research carried out for this report confirms the persistent gap in publicly available ex-post evaluations of energy efficiency programmes.