This is an analysis of the existing building that allows us to examine what level of energy usage a client’s home currently has, how it is constructed and how well or badly insulated it is, before proposing a range of options for upgrading the building fabric.

The process begins with a site visit and conversation with the client to understand their ambitions, how they use the house and what other changes are being considered as part of any construction works. The assessment is most often undertaken for clients who are extending or undertaking significant refurbishment anyway, but can also be a useful stand alone study.

The building is modelled using the passivhaus software, PHPP. This allows us to assign different U- values to the floor, walls, roof and glazing of the building and then test out different proposals for improvement. Depending on the project, we may look at different proposals for different storeys of the building (for example when a project is to be phased or historical features and conservation restrictions mean that a different solution is required).

Using the analysis, we work with clients to develop an approach to retrofitting their home which is mindful of their budget and the limitations of working in buildings that may be listed or in a conservation area. This might be a whole house retrofit, or could be a phased approach, in which case we consider how to balance the works that may have the biggest impact with those that would be difficult or unrealistic to do later.