OFT criticises energy efficiency sales techniques
10 January 2013 Last updated at 11:47 GMT
High pressure sales techniques have been used by some energy efficiency companies a review by the Office of Fair Trading (OFT) has found.
The regulator also revealed that there was often a lack of clarity in paperwork used by double glazing, insulation and solar panel installation companies.
The OFT's Nisha Arora told BBC News that guidance had been issued to businesses to instruct them to treat customers properly.