Although I had plenty of ideas, as a second opinion I commissioned a report from Parity Projects. They have retrofitted an older semi-detached house in Carshalton which I visited last year. Their report primarily looked at the existing status of the house, the options and then what would be the most cost effective and CO2 effective energy saving measures to take. They summarized their recommendations for my house into three categories: no cost measures, low to medium cost measures and higher cost measures.
- Low cost included disconnecting the electric heaters in the airing cupboard and only washing clothes at 30 degrees
- Medium cost included insulation in the loft, draughtproofing, blocking passive vents, insulating cavity walls, replacing appliances with top energy rated appliances and replacing light bulbs with low energy bulbs
- Higher cost included underfloor heating, installing a new condensing boiler and installing a solar hot water system
They estimated that these measures together would save the average occupier of the building about £650 a year and reduce their CO2 emissions by some 60%.
They also listed some general energy and cost savings that anyone can make in the way they live in their house, to which I have added my thoughts from my own experience (see eco living).
Heat Loss Report
A kind colleague from our Transition Town Energy Group prepared an energy report for me and did extensive heat loss calculations for the house. Many of the recommendations are similar to those in the Parity Projects report (I'm glad the experts agree!). For example filling the cavity walls was estimated to reduce the heat loss through the walls by about 40% and proper insulation in the loft space could save about 80% of the heat loss from that area. Upgrading windows and insulating the floor would also make good savings.
The document provides a detailed technical assessment and it may be helpful if I get round to doing a before and after assessment of the changes I have made. The report also gives energy saving tips which are incorporated into the eco living section.
T ZERO
There is a new web tool available for refurbishing existing buildings to good environmental standards. Having tried it out, it seems a bit simplistic and doesn’t take account of detailed individual circumstances so can give a false impression of costs and payback. Their costs anyway are far too optimistic given my experience. However, it is a useful tool when starting out on a project of this nature.
See www.tzero.org.uk/Homepage.aspx
Using this tool gives an idea of what are effective measures to carry out both in terms of CO2 savings and cost savings. For a house like mine, the measures that would pay for themselves within about 5 years according to this model are:
Loft insulation
Cavity wall insulation
Draughtproofing
Low energy light bulbs
Gas condensing boiler
Log stove
However, the model does not take account of the cost of the insulation I am using, the fact that the existing boiler is reasonably efficient and that my quote for a log burning stove is 50% more than they estimate. Even so, it is a guide that tallies with the works I planned to do.
What to do?
This is a superficial guide, but suggested suggest that cavity wall insulation, low energy lighting and upgrading the heating controls would bring the energy efficiency up substantially and improve the environmental rating.