ANNUAL COLLOQUIUM 2011 The Expanding House Extensions to

ANNUAL COLLOQUIUM 2011 The Expanding House: Extensions to Domestic Buildings and their Impact on Energy Consumption Richard Jack Supervisors: Prof Kevin Lomas & Dr David Allinson Findings of Master of Research Dissertation Annual Colloquium Presentation Thursday 10/11/11

The Expanding House 2 The Context 17% of total UK energy demand is accounted for by the residential sector, 01 cutting this demand is a policy priority. Archetype based stock models are one of the tools used by policy makers to design the most effective interventions. • • • Sample of 575 houses in Leicester 19% Extended Catalogue of extension types created with data for typical size and prevalence Project Objectives The project sought to define whether extensions to domestic buildings account for a significant proportion of the UK’s total domestic demand what implications this has for the archetype based stock modeling approach.

The Expanding House 4 Impact of Extensions on Energy Consumption Extension’s Impact on Energy Consumption CO 2 Saving 40% 35% Across Extension Types: 01 Increase in energy consumption: 7% - 33% Mean increase: 16% Maximum Heating Efficiency Savings 30% 25% Image area 20% 15% 10% Appliance Energy Savings 5% 0% Terraced Solid Wall Insulation Water Heating Efficiency Measures Semi-Detached Cavity Wall Insulation All Gas Boilers Condensing Potential CO 2 Savings [Firth & Lomas, 2009] The Conclusion Extensions have been estimated to account for a 4% increase in English domestic energy consumption compared to an unmodified stock. This is of similar magnitude to the impact of a typical energy efficiency retrofit such as insulation for all solid walls. Therefore, extensions play a significant role in the energy consumption of the UK stock which should be accounted for in stock models.