British Gas has launched a green energy business to help customers reduce their carbon emissions.
British Gas New Energy will sell and help install rooftop solar heating panels for customers to heat their own water, and will give people the chance to offset their CO2 emissions through schemes that buy credits from other firms or countries that have exceeded their own targets.
In addition, customers who buy the solar panelling in some areas will be able to earn a discount of up to £500 (€735.83) on their council tax bills through an agreement between British Gas and the local authorities.
The solar panel scheme is currently running in five areas, but British Gas said it expected it to be adopted by more local authorities in time.
The business will also provide Energy Performance Certificates, which give energy ratings for homes, and will be mandatory for those selling properties after June 1 this year.
Parent company Centrica estimates the green energy market for homes and businesses could be worth several billion pounds a year, and it has also pledged to cut its own energy usage by 10% by the end of the year. Its hot water solar panels cost from £4,300 (€6,329).
The new service builds on current schemes available through British Gas' residential business such as its council tax rebate for people who install loft and wall insulation and the provision of high efficiency boilers.
It is also working on a next-generation fuel cell boiler for homes that produce both heat and electricity and could reduce household emissions by up to 50%.
Sam Laidlaw, chief executive of Centrica, said: "Most UK homes are poorly insulated and the energy loss and emissions levels from them are much higher than they could be."
British Gas added it would take a number of years for the new business to have a material impact on earnings.