The Geneva Grand Council is debating whether to offer financial help to homeowners who wish to install more sustainable forms of heating.
The discussion on Friday were described as ‘lively’ by the press.
The idea is for the canton to pay half the cost for all renovations.
But the finance minister Nathalie Fontanet described the cost as ‘monstrous’ as it could cost billions.
The bill will return to the council in the next session, but the backers, the Socialists and the Greens are already talking about taking it to a referendum.