Home Energy Group

There is at present, no functioning Home Energy Group, although there has been a little activity around the subject.

Energy Advice sessions have been run in the Old School Centre, by South Dartmoor Community Energy, offering free and impartial advice. These focus mainly on switching energy supplier, as a quick and easy way to save money. But advice is also available on reducing draughts, insulation, and reducing electricity use.

Government grants for insulation etc., are now a thing of the past. Initiatives like the Green Deal,  were ineffective. Other government policies  have brought swingeing changes to renewable energy installers, and de-motivated some sectors. So we are on our own, apart from the renewable heat incentive, and existing agreements providing subsidy.

It is hoped that by linking with other Transition or sustainability groups, a program of events will be organised, to take place later this year.

Suggested topics include:

CARBON  FOOTPRINTS:- how are we doing?

HOME HEATING:- a comparison of options.

KEEPING WARM ENOUGH- practical improvements.

DRAUGHTS AND VENTILATION- getting in control.

Some potential members of a re-forming Home Energy Group, have made themselves known, and we are keen for more to join us. Aspects of the subject can be dry, so a sense of perspective, and a sense of humour, would be very desirable attributes to bring.

Guidance to retro-fitting old houses (2016)

Report Joddy Chapman, SSB Trustee

On a blustery Friday in May I attended a day-long series of lectures on energy saving in older buildings at the Dartmoor National Park Authority (DNPA) headquarters near Bovey Tracey. Introduced by Jonathan Garlick, Technical Officer of the Society for the Protection of Ancient Buildings (SPAB) and titled “Fit for the Future: latest research and guidance on appropriate retrofit”, this technical session was aimed at architects and building professionals but included a condensed version of the “Old homes eco-course” run the following day for home-owners.

The morning session was presented by Caroline Rye, who together with Cameron Scott works for Archimetrics Ltd, a company offering specialist research services into the energy performance of old buildings. Commissioned by the SPAB, she described the in-situ measurements of heat and water vapour movement through walls on different houses before and after various sold-wall insulation measures had been installed.

Houses built up to around 1919 typically have thick, solid walls with no cavity or damp course and it is often assumed that they have poor thermal performance. The good news is that from the measurements made on real walls, it is generally the case that they are not as bad as previously thought and certainly not as bad as the government’s Standard Assessment Procedure (SAP) predicts. This is especially the case for rubble stone walls, which contain voids and varying thicknesses of mortar.

The bad news starts when people apply modern insulation methods to old, solid, walls. ‘Breathability’ Essential: Owners of older buildings are becoming increasingly aware of the need to maintain the “breathability” of their home, by which it is meant the ability of the fabric to transport, store and release water vapour. Vapour permeability and hygroscopicity are the correct technical words, since breathability may be confused with draughtiness. Problems start if impermeable paints and render (such as plastics based paints, gypsum plaster and concrete) are used, which prevent the building fabric from working properly. In the worst cases (such as concrete render on cob walls), damp will build up in the wall until it loses its structural integrity and collapses.

The research shows that applying thick, modern foam based insulation inside a solid rubble stone walled building leads to ever increasing dampness within the wall, since it will be both colder and less able to dry out. More sympathetic materials, usually incorporating lime and natural fibres, have been shown to reduce heat loss but allow sufficient heat transfer for the wall to remain warm enough to prevent water vapour from condensing inside the wall and to escape back through the insulation.

The afternoon session was presented by Marianne Suhr and Roger Hunt, authors of the SPAB book “The Old House Eco Handbook”. This comprised a canter through the options available for reducing heat loss through walls, roofs, doors, windows and floors. The main lesson is that a building should to be considered as a whole, and very great care is needed in selecting the appropriate measures to take.

The day was sponsored by Dartmoor National Park Authority and run by the SPAB – our thanks to them both.

There is now quite a lot of information available on this subject, much of which can be found on English Heritage’s website and from the SPAB. Sustainable South Brent has purchased a selection of publications which are available in the Old School library. It is likely that SSB will host a discussion evening on this topic in the autumn – watch this space!

USEFUL REFERENCES:

  • SPAB: Energy Efficiency which contains links to the research results presented by Caroline Rye.
  • Saving Energy | English Heritage A useful series of leaflets describing how different building elements can be improved. Also available in the Old School library.
  • SPAB technical advice line: 0207 456 0916
  • Old House Eco Handbook, Marianne Suhr and Roger Hunt, 2013, ISBN 978 0 7112 32785, published by Frances Lincoln, printed in China (oh dear…).