§ Brian White
To ask the Secretary of State for Trade and Industry what the average cost of installing(a) photovoltaic cells and (b) external wall insulation on a house was in the last year for which figures are available; and what public subsidies are available for this work. 
§ Mr. Timms
PV average cost based on a three-bed semi detached household system of 2kWp capacity.
Depending on the type of system specified, total average costs for a 2kWp system are between £13,000 and £17,000. Under the Major Photovoltaic Demonstration Programme 50 per cent. is available in grant.
External wall insulation costs:
The marginal cost for externally insulating a three-bed semi detached house is approx 1500. The costs vary greatly according to house type and building height. Public subsidies are not available for this technology.