A string of harsh winters and a raft of financial incentives have created a growing interest in insulation which offers real opportunities for installers, according to new research by the Energy Saving Trust (EST).

The survey showed that more than a million UK homes have fitted wall or loft lagging in the last year, while a 13 million homes still have under-insulated lofts. A quarter of all UK homes (6.5 million) still have un-insulated cavity walls.

More than a fifth of those questioned in the EST survey (21%) said they were "very interested" in fitting insulation to their home, with many keen to cash in on the end of the government's Carbon Emission Reduction Target (CERT) scheme, which offers grants to pay for cavity wall or loft insulation until December 31.

The Green Deal will be launched in January and supersedes the CERT scheme, and the EST is inviting insulation installers to get registered to take advantage of the increased interest in insulation.

EST is an independent organisation which can provide Green Deal installer certification at a fixed price. All installers approved by the EST are also given a free listing on the organisation’s website.

Stephen Passmore, an EST housing expert, said: "It's clear that more and more people are taking insulation seriously – after all, it can literally stop your money going up in smoke.

"We're encouraged that so many homeowners have fitted insulation in the last 12 months, and further heartened that 21% are very interested in following their example.

"Green Deal lets householders pay back the cost of energy-saving improvements over time through their energy bill. Anyone performing Green Deal work must be certified, and the EST is one organisation making sure that only trusted tradesmen can operate under the scheme.

"Our figures show there is still a huge opportunity for installers to continue insulating homes across the UK through the Green Deal. With certification and the right information showing which homes could benefit from insulation then installers can maximise the opportunities of this initiative for themselves and householders."

Green Deal enables private firms to offer consumers energy-efficiency improvements to their homes, community spaces and businesses with no upfront payments. Costs are recouped – as savings accrue – through a charge in instalments on their energy bills, with money passed on direct to Green Deal providers by energy companies.

Installers interested in working with the EST should visit www.energysavingtrust.org.uk/Organisations/Business-services/Green-Deal-certification or contact greendealcert@est.org.uk.

Homeowners wanting more information on insulating their home can visit www.energysavingtrust.org.uk/Insulation or call the EST helpline on 0300 123 1234.