Yesterday, the Berkeley City Council moved to eliminate one of the biggest obstacles to making homes more energy-efficient: the upfront cost.

In a move being watched by other cities around the country, the Berkeley Council unanimously approved a program to give city-backed loans to property owners who install rooftop solar-power systems. The loans, which are likely to total up to $22,000 apiece, would be paid off over 20 years as part of the owners’ property-tax bills.

This is the first time that a special property tax district has been created expressly to help retrofit homes and businesses to reduce electrical use. The only piece of the puzzle still missing: a deal with a lender whose capital the city would use to finance the program.

At first, Berkeley seeks to raise $1.5 million for a pilot program for about 50 homes. If its program is successful, the kitty could eventually contain tens of millions of dollars, and hundreds of property owners could be eligible.

The city’s mayor, Tom Bates, said in an interview shortly before the vote, “I think this is probably the most important contribution Berkeley can make toward taking on global warming” and reducing greenhouse gases.

He added, “I think the idea is going to go like wildfire” through other city governments. He said nearly two dozen cities, from San Francisco to Annapolis, Md., and Seattle to Cambridge, Mass., had called, indicating they wanted to follow suit.

Participating homeowners would pay roughly $180 more per month on their property tax bills, though the hope is that much of that cost would be recouped in savings on electric bills.