Energy Efficiency

SPAB ENERGY EFFICIENCY RESEARCH

The SPAB Research Report 1. U-value Report

Energy efficiency is becoming the key issue for people working with historic buildings. SPAB believes that if approaches aren't based on the right figures to begin with, then we could, unintentionally, be doing untold, invasive damage.The initial objective of the SPAB research project was to fit in with the work begun by Historic Scotland (http://www.historic-scotland.gov.uk/technicalpapers) and English Heritage (http://www.climatechangeandyourhome.org.uk/live/saving_energy_in_buildings_intro.aspx).  Historic Scotland has produced a various reports , looking mainly at the performance of sandstone construction, while English Heritage is currently looking at brick construction. SPAB felt a responsibility to represent other nationally important traditional walling types such as, wattle & daub paneling, cob, limestone, slate, granite etc. These traditional materials often get overlooked, but, from a historical perspective, they probably have the most to lose in terms of standard assessment.

Results from the first stage of SPAB's (The Society for the Protection of Ancient Buildings) research on the energy efficiency performance of old buildings suggest that standard U-value calculations used across the construction industry underestimate the thermal performance of traditional walls. In some instances, it now appears that heat loss through vernacular materials can be up to three times lower than expected.

The initial study suggests that conventional industry practices are struggling to accurately represent the thermal performance of traditionally built walls. Ultimately, this could have negative consequences for historic buildings as calculated theoretical U-values (suggesting a poorer performance) may lead owners and professionals to adopt disproportionate energy saving interventions that may not only be unnecessary, but also invasive and potentially harmful to the fabric of a building.

SPAB's report, written by Dr Caroline Rye, formerly MSc student at the University of Portsmouth, compared the in-situ U-values (U-value is the universally known unit to describe the rate of heat transmittance or loss through a wall / roof / floor etc) of various traditional vernacular walls against the theoretical U-value for these walls using the class-leading BuildDesk U 3.4 software. Importantly, the theoretical value obtained from the U-value calculations is used by professionals as the base-line for assessing thermal performance of different types of constructions. However, SPAB's on-the-spot research suggests that 79% of the traditionally built walls sampled -- including walls of timber, cob, limestone, slate, and granite -- actually perform better than expected.

Jonathan Garlick, SPAB technical officer explains: "It's all about understanding the building first -- how it performs, how we use it and how we live in it. U-values are not the complete story. Energy efficiency is also about our behaviour in a building, moisture content in the structure, humidity, temperature, air-tightness, the quality of the air we breathe. These are all issues that we intend to consider in further stages of the project."SPAB's energy efficiency project continues throughout 2011. Research is already underway on air-tightness, moisture and air quality.  Later this year the team will return to buildings constructed from traditional materials that were first assessed in an 'as found' state and which have since been upgraded to enhance their energy performance.  In an effort to relay the results as quickly as possible a SPAB Technical Day (Old Building Energy Efficiency Research: The Latest Thinking & Results Update) has been organised for 18th October 2011. All are welcome.

Jonathan Garlick says: "We believe that this important research will at last reveal some fascinating and useful information to help people make beneficial, effective and appropriate decisions about their old buildings without the need to destroy historical fabric or harm the indoor environment in the process."

Here's a direct link to the Youtube piece on the SPAB energy efficiency project: http://www.youtube.com/watch?v=2trqe3c3DBY

Or alternatively, please go to the following location on this website: http://www.spab.org.uk/videos-podcasts/audio-slideshows/

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THE SPAB RESEARCH REPORTS 1, 2 & 3

To download the SPAB Research Reports, please click on the following links:

The SPAB Research Report 1: U-value Report, revised October 2011 - click here.

The SPAB Research Report 2: The SPAB Building Performance Survey: Interim Report, October 2011 - click here. 

The SPAB Research Report 3: Hygrothermal Modelling: Interim Report - This report will be uploaded shortly. To register your interest in the Report, please email: technical@spab.org.uk.