The contractor said the deal, which will see 3,500 Cross Keys Homes properties in Peterborough fitted with the panels, is the largest in the UK social housing sector so far.
Mears entered into a partnership with British Gas in September 2010 with the aim of funding energy efficiency improvements to 500,000 social homes.
For the Peterborough scheme British Gas will fund the installation of the panels, and will make money back through the government’s feed-in tariff. This makes a payment for every kilowatt hour of electricity generated from the panels.
Mears will carry out some of the installation work, as well as associated electrical and scaffolding jobs.
The first panels are expected to be fitted next month, with all the work finished by April 2012.
David Miles, chief executive of Mears Group, said: ‘We see increasing opportunities in this area into 2012, particularly as the green deal and other energy efficiency measures come into play.
‘Cross Keys will provide us an important reference site to lead our drive into this emerging energy opportunity as we continue to successfully leverage our partnership with British Gas, which gives us access to both funding and expertise in this area.’