The Home Energy Rating Act, if passed by Queen's Park, would require anyone selling a house or low-rise building to disclose the results of a home-energy audit to prospective buyers.
Sellers of new homes would also have to supply energy-efficiency ratings before making a sale.
"I think we've got all-party support for this," said Liberal backbencher Phil McNeely, who introduced the bill.
McNeely said homebuyers are looking at energy prices and becoming increasingly concerned about the higher cost of owning a home, not just buying it.
He said efficiency ratings will spur greater demand for new and resale homes that use less energy, ultimately increasing their property value compared with less-efficient homes and pressuring new home builders to go beyond the minimum standards in the building code.
"We totally endorse this bill," said Peter Hwang, co-founder and chief executive of Toronto-based EnWise Power Solutions Inc., which does home energy audits and retrofit work for homeowners.
"If it does anything it heightens awareness of energy efficiency, making it one of the most important ways of improving a home,'' he said.
Ken Elsey, president of the Canadian Energy Efficiency Alliance, called it "the most significant piece of legislation in years" because it uncovers the true cost of home ownership and will pressure sellers to do efficiency upgrades before they put their property on the market.
"It will also serve as an economic and employment stimulus," said Elsey, referring to the increased demand for energy auditors, retro-fitters and energy-efficient appliances and materials.
The requirement would apply to all newly built homes in 2010, followed in 2011 by detached, semi-detached and multi-unit residential buildings put on the market for resale.
In 2012, those leasing buildings would also have to supply the ratings.
McNeely said the bill passed its second reading and now goes to committee, where most private members' bills end up dying.
He's counting on Energy and Infrastructure Minister George Smitherman to carry it from there.
"If the minister likes it, then he could pick it up and put it into legislation fairly quickly," McNeely added.