British Gas is to join with housing charity Shelter to carry out a "census" of private rented homes to find out where the energy supplier can help improve their condition.
The census follows a government English Housing Survey that revealed 1.4 million homes in the private sector would be rated as 'unfit' under the government's decent homes standards.
The government survey found more than 600,000 privately rented homes had inadequate thermal comfort; 856,000 had inadequate health and safety - such as poor electrical safety - and 322,000 were in a state of disrepair, suffering from poor glazing or broken heating systems.
British Gas said it hoped the new census, which should report in early 2013, would reveal which areas had the worst problems and which were issues like poor insulation or central heating that would be within the energy company's area of expertise.
The two organisations said the survey is the start of a five-year partnership to improve rented accommodation that would include helping landlords to meet statutory minimum standards, and making policy recommendations.