The Tories have voted for a tax cut - on VAT on energy-saving light bulbs.
Domestic energy use accounts for 27% of the UK's CO2 emissions
Activists threw their weight behind marketing manager Mark Menzies' plan during a "Dragons' Den" style contest at the party's Bournemouth conference.
Mr Menzies, who contested Selby in 2005, said the cut would help people do their bit for the environment.
He admitted having only one of the bulbs in his home, but said his plan was simple enough to explain to people on their doorsteps.
Ex-Cabinet Minister Ann Widdecombe, a member of the "Dragon" panel of judges, advised him to buy some more "before the press come round tomorrow".
Members applauded as Mr Menzies said: "If we are serious about using the tax system to help the environment, taking tax off energy-saving light bulbs is a fantastic place to start."
He said the scheme to remove VAT would involve a small cost to the Treasury but would result in less energy being used across the country.
His plan was backed by 64% of members who voted in an interactive vote at the end of the session.
He will now have the chance to discuss it in detail with party policy chief Oliver Letwin.