This dataset was generated through a mixed‑methods approach designed to capture both quantitative performance data and qualitative stakeholder perspectives relating to the B&NES sustainable construction policies. First, all eligible planning applications submitted between May 2024 and June 2025 were systematically reviewed. Energy summary data, SAP/PHPP modelling outputs and associated documentation were extracted to assess compliance with operational energy and embodied carbon requirements. These submissions were analysed at the individual‑plot level, enabling comparison of design parameters such as space heating demand, total energy use, U‑values and air permeability.

To complement this, a structured questionnaire was distributed to planning agents and consultants to gather insights into applicant experience, perceived challenges and evolving practice.