The main documents are the Retrofit Handbook and the Climate Action Supplementary Planning Document.
Along with several helpful checklists, reports, a template for a part of a planning application and the Islington Permitted Development Guide for Net Zero Works these are available by following the links at: islington.gov.uk/planning/applications/permission-check.
The Retrofit Handbook is applicable to buildings in many inner cities, not just houses in Islington, except where it focusses on four widespread housing types – Georgian houses, Victorian houses, early 20th century flats and mid-20th century houses.
For each of these it shows the reductions in energy demand and greenhouse gas emissions, as well as the costs, of three retrofit projects labelled ‘DIY’, ‘medium’ and ‘comprehensive’.
Each project lists measures that might range in complexity from changing light bulbs through replacing windows to installing heat pumps.
Much of the Retrofit Handbook contains details of such measures.
DIY ones include draught proofing, changing radiator valves and removing paving; more complicated ones include insulating walls, recovering ventilated heat and installing solar panels.
There are many measures to choose among for a retrofit project.
The choice should be related to the general expectations discussed early in the Retrofit Handbook – electrifying heating, controlling ventilation, reusing materials and preserving heritage.
Doing so leads to treating the ‘whole building’ as one system, not as several separate parts, and arranging the measures according to how they work together.
For instance, the ‘fabric first’ arrangement would reduce heat loss as much as possible before electrifying heating; in an alternative, sometimes called the ‘fabric fifth’ arrangement, installing heat pumps and solar panels would have precedence over insulating walls, which is difficult and disruptive.
Whatever measures are taken, they should give the best reductions in energy bills and greenhouse gas emissions having tolerable cost and disruption.
Though the Retrofit Handbook provides technology details, it discusses the planning rules only for four retrofit measures – external wall insulation, window replacement, air source heat pump installation and solar panel installation.
For others it leaves the discussion to the Climate Action Supplementary Planning Document and the Islington Permitted Development Guide for Net Zero Works. Those would require other articles.