A dataset of 45 Word documents containing anonymised transcripts of semi-structured interviews with a variety of stakeholders linked to the design and development of office buildings and the implications for energy demand. The majority of the interviews are with architects, Mechanical & Electrical engineers and letting agents associated with 10 case study buildings built or refurbished 2010-2015 in London UK, in a speculative development mode. The dataset also includes examples of a consent and information form used to secure an interview, and a template schedule that shows the sorts of questions that framed the interviews.