Consumers who want to insulate their homes should watch for high-pressure sales tactics, dodgy information and poor installations as some firms may be breaking the law, the Office of Fair Trading (OFT) says.

The OFT has written to over 50 firms in the double-glazing, insulation and solar panel industry to remind them of their responsibilities after a review found the behaviour of some energy efficiency firms raised "particularly significant concerns".

It has launched an investigation into the sector after it found some consumers had been given misleading or inaccurate information about the energy they could save, or about their eligibility for a grant or subsidy.

The OFT also discovered some firms used high-pressure selling techniques, including salespeople staying in consumers' homes for several hours, or indicating that products were only available at a discount if they were bought immediately.

There is no suggestion the firms the OFT has written to are in breach of the law. But it adds that under consumer protection law, providers must make sure paperwork and documents are clear, and tell consumers of their rights to cancel.

The OFT's director in charge of the sector, Nisha Arora, says: "Many businesses in this sector comply with the law and engage in good business practices, but we urge others to raise their standards.

"Businesses that fail to address the issues that we have identified risk enforcement action."

Free or cheap insulation

Those on benefits may be able to get insulation paid for. See our Free Insulation guide.

A government scheme called the Green Deal also starts later this month which gives all households access to loans for energy improvements.

Energy efficiency buying tips

If you're planning on buying energy efficiency products, the OFT has this advice:

  • Take your time in making a decision. If you are promised a "special discount" or "time limited" offer, don't be tempted to sign up straightaway. Compare different firms to get the best deal.
  • Double-check the facts. Check the product is suitable for your home, whether you are eligible for any grants towards the cost of installation, and the basis of any claims about potential energy savings or benefits.
  • Know what you're signing. Check whether you are signing a contract or just agreeing to a survey or a quote. Take time to read the paperwork, and don't sign anything if you are unsure.
  • Know your cancellation rights. If you buy on the doorstep or in your home and spend more than £35, you usually have seven days to cancel and get a refund of any money already paid, including a deposit during the cooling-off period. This starts on the day you are given your written cancellation notice by the salesperson.

For further information on your rights if something goes wrong, see our Consumer Rights guide.