Derby's annual carbon footprint has been reduced by more than 4.5 tonnes with the help of city council grants, the council has said.
So far £10,000 in energy efficiency grants have been handed out to firms in the city from a total fund of £130,000.
A builder and a children's play centre installed insulated roller shutter doors and new fluorescent light tubes.
This scheme, due to run until spring, is being run in partnership with Groundwork Derby and Derbyshire.
Councillor Matthew Holmes, deputy leader of Derby City Council, said: "I hope that even more businesses are inspired by these initial grants and will get in touch to discuss with us ways they can apply too."
Under the scheme, the full cost of any energy saving improvements costing up to £500 will be covered.
Improvements costing from £501 to £2,500 can have 90% of the costs covered and those costing more than £2,500 can have up to 80% covered, up to a maximum grant value of £5,000.