PORTLAND — City councilors are expected to vote Monday on a package of energy efficiency projects in nearly four dozen city-owned buildings Monday that will cost about $12 million, although the money is expected to be recouped through lower utility bills.

The projects come from an energy audit conducted earlier this year by Ameresco, a Massachusetts-based consulting firm, which recommended a range of steps to save energy, from changing light fixtures to upgrading boilers, installing new windows and replacing roofs. The company has said the projects will save about $700,000 a year in utility costs and by the end of a 20-year period, will pay back the cost of the work and interest on the bond, and produce about $1.5 million in additional savings.

The final list calls for work on 30 municipal buildings and 15 school buildings, although some of the school projects are among the more expensive, such as more than $1.2 million for Lyseth School and nearly that much for King School.

The building with the single biggest price tag is the city’s nursing home, the Barron Center, where the city plans to spend about $2.4 million on energy efficiency items, including $1.4 million for new boilers.

The city has bundled the projects into an $11 million bond package. The rest of the cost will be covered by federal grants, said Nicole Clegg, the city’s spokeswoman.

Steven Scharf, president of the Portland Taxpayers Association, said he objects to taking the items as a package, and would prefer that the council either vote on each project individually or send the entire bond proposal to a referendum for voters to decide.

The city charter sets a limit of about $4 million on bonds that the council can adopt without voter approval, but carves out an exception if the bond covers individual projects costing less than that amount.

Clegg said the city uses the same procedure of putting a number of different projects in one bond issue each year when it passes a capital improvements budget and bond, without sending the proposal to voters. She also noted that bond measures need to be passed by a “super-majority” of seven of the nine councilors, rather than a simple majority of five.

Scharf said the council needs to take a look at some of the projects recommended by Ameresco, including nearly $15,000 for the school district’s central kitchen in the Reed warehouse, which is expected to be closed soon. He also noted that the package also includes more than $200,000 for the East End Community School, which is the city’s newest school and is just three years old. If such a new school already needs a significant amount of upgrading to make it energy efficient, Scharf said, the city should go back to architects and engineers to find out why more energy efficient materials or systems weren’t used in the first place.

Staff Writer Edward D. Murphy can be contacted at 791-6465 or at: emurphy@pressherald.com