ANNUAL COLLOQUIUM 2011

The Expanding House: Extensions to Domestic Buildings and their Impact on Energy Consumption

Richard JackSupervisors: Prof Kevin Lomas & Dr David Allinson

Findings of Master of Research DissertationAnnual Colloquium Presentation Thursday 10/11/11

The Expanding House

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The Context17% of total UK energy demand is accounted for by the residential sector, 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.

Project ObjectivesThe project sought to define whether extensions to domestic buildings account for a significant proportion of the UK’s total domestic demand and what implications this has for the archetype based stock modeling approach.

• Sample of 575 houses in Leicester

• 19% Extended• Catalogue of

extension types created with data for typical size and prevalence

The Expanding House

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Impact of Extensions on Energy Consumption

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Terraced Semi-DetachedDetached Potential CO2 Savings [Firth & Lomas, 2009]

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Maximum Heating Efficiency Savings

Appliance Energy Savings Solid Wall Insulation

Water Heating Efficiency Measures

Cavity Wall Insulation

All Gas Boilers Condensing

Across Extension Types:Increase in energy consumption: 7% - 33%Mean increase: 16%

The ConclusionExtensions 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.