Evaluation of building and systems performance for a deep domestic retrofit

European governments have set ambitious retrofitting targets driven by the commitment to reduce the greenhouse gas emissions by at least 80% by 2050. The United Kingdom has the oldest housing stock in Europe, with over 2/3 of dwellings built before 1976, when building regulations started to include energy efficiency. This raises concerns over carbon emissions, health, comfort and running costs, and government’s set targets and initiatives for significant improvements. Deep retrofitting by using innovative technologies with respect to aesthetics has considerable and measurable benefits, while it can be a costly and challenging process. This study examines a combination of measures undertaken in a pre-1919 dwelling in south Wales, including reduction of energy demand and the application of renewable energy supply and energy storage. A whole house performance and a systems breakdown evaluation is presented comparing the pre and post intervention status. Both monitoring and modelling tools where used, and the performance gap is also discussed. An annual reduction of 34% in space heating and 78% in electricity import was monitored with an additional electricity export of 3217kWh. This represents a total annual cost saving of £1115, at 2019 UK gas and electricity prices. The total cost of the retrofit was £55K.