Most people working in London want to work for companies which have polices to help the environment, according to figures released by the Carbon Trust.
The organisation said 92% of employees want to cut their own personal energy use to help tackle climate change.
But 25% of the 1018 surveyed felt their company was not doing enough to cut its carbon dioxide (CO2) emissions.
The trust campaigns for a reduction in CO2 emissions and gives advice on how to establish positive energy campaigns.
The trust's Dr Garry Felgate said: "The majority of London's employees want to become more environmentally friendly at work, but many don't know where to start.
"It's in a company's best interest to help them, as adopting simple energy efficiency measures could save up to 10% on energy bills.
"Our research shows that one out of four workers in London doesn't switch off the lights in a room that is not being used, but nearly all (96%) say they do when they're at home.
"Simply by encouraging employees to bring their good energy habits into the workplace, businesses in London could reduce lighting bills by around 19% a year, not to mention significantly lower their carbon emissions."
Last week, the government admitted it was unlikely to meet its 2010 target for reducing CO2 emissions.