BRUNSWICK, Maine — The cost of renovating Brunswick’s new town office is mounting, although the building could also provide some expense savings over time.

The Town Council on Monday received an update from Town Manager Gary Brown on the renovation project, which began this week.

Renovations on the new Town Hall at 85 Union St. have increased to $992,000, but only after the council’s Town Hall subcommittee asked for about $18,000 in reductions from Warren Construction’s proposed budget.

On the other hand, Brown estimated that annual operating costs of the building will be about $200,000, about $15,000 less than it costs to operate the separate offices that will consolidate into the Union Street building.

The town is expected to move into the building, now used by Bowdoin College as the McLellan Building, from the current town office at 28 Federal St. in late March 2014, Councilor Margo Knight said.

The renovation figure includes about $903,000 in construction costs and nearly $89,000 in architect fees, bringing the total about $42,000 higher than the $950,000 expenditure of unassigned funds approved by the council on Nov. 18.

Brown said the costs in excess of approved expenditures will be covered by $50,000 appropriated in this year’s budget for the building’s design costs.

However, the costs of upgrading the building don’t stop there.

Because of a bidding form mistake, the cost of a $90,000 power generator wasn’t in the budget and will likely be dealt with sometime during late summer or early fall in the next fiscal year, Brown said.

“Hopefully between late March and sometime in July or August we won’t suffer any weather conditions that will result in any power outages,” he said. “It’s not really likely during that time of year.”

In addition, the replacement and repair of rotting wood on the building’s sides won’t be addressed until one of the next two fiscal years, Brown said, although he did not provide a cost estimate.

The Town Hall subcommittee asked for about $18,000 in reductions from the project budget, Knight said, after Warren Construction revealed on Dec. 9 that renovation costs were “much higher than expected.” At the time, most of the subcontractor costs had just come in.

Knight said cuts were made “without sacrificing what we actually need.”

The cuts include tempered glass with an etched town seal that would have been in the new Council Chambers, window grills and a set of folding doors.

Brown said the new town office will provide more meeting space for town boards and organizations with the Council Chambers, one large conference room and two smaller conference rooms.

He added that because all of the doors have card readers that will allow timed entry depending on a person’s privileges, there won’t be a need to have town staff around just to open and close the building for different meetings.

“I’m absolutely convinced that this was a right decision and a good decision by the council,” Brown said.

The council agreed in October 2011 to swap the former Longfellow Elementary School for the 85 Union St. building with its current owner, Bowdoin College. It also granted Bowdoin 10 years of free rent on the building’s third floor after the town takes ownership.

The former elementary school has since been reopened as Bowdoin’s Edwards Center for Arts and Dance.

When the town moves into the new Town Hall, it’s expected to transfer the 28 Federal St. property — and sell the former recreation center, at 30 Federal St., for $225,000 in a separate agreement — to Brunswick Development Corp.

The council had previously agreed with BDC to swap the 28 Federal St. property for property that has since become the new police station at the corner of Stanwood and Pleasant streets.

When the town transfers the Federal Street properties, BDC is expected to close on the sale of both properties for $300,000 to Wiscasset-based Coastal Enterprises.

The nonprofit company has signed a purchase option with BDC and is considering moving its headquarters and 60 jobs to downtown Brunswick.

Brown said he estimates the combined properties will generate up to $70,000 in property taxes every year.