The Cosy Homes Group has funding available through the Energy Efficiency Conservation Authority (Eeca) to insulate up to 1500 houses in Dunedin.
Cosy homes chairman Jeff Donaldson said 100 people had signed up in the first week, which was fewer than they wanted.
The subsidies are only available to Cosy Homes for work done by the end of June but Mr Donaldson said there was plenty of scope for the two contractors involved to do the work.
He said one of the contractors was having to work in Balclutha at the moment because there were not enough homes to do in Dunedin.
Anyone with a community services card who owns or rents a house built before 2000 would qualify.
Ring Right House Ltd on 0800 744-569 or Smart Energy Solutions 0800 888-766 to sign up.
