The United Kingdom is aspiring to reduce the carbon emissions in the building sector, aiming to achieve nearly zero carbon buildings by 2020. The policy models in England and Wales rely on three strands: regulations; financial incentives and educational schemes. A growing body of literature suggests that the building industry is facing several barriers that hinder the delivery of the expected carbon targets outlined at policy level. This research explores the enactment of the policy aspirations by building designers using a bottom-up approach. An ethnographic study was conducted to analyse the design process of six non-domestic buildings. The work identified the designers' responses to adopt the policy agenda in routine design and overcome the challenges that emerged during the design process. The understanding of the designers' responses could inform the policy model and suggest areas that need attention for the timely delivery of the expected carbon reductions. (C) 2014 Elsevier Ltd. All rights reserved.