Major employers don’t uproot thousands of employees from over a dozen locations and put them in a brand-new building without significant forethought.

Partners HealthCare considered 55 locations in Greater Boston before settling on a new build-to-suit headquarters at Assembly Row in Somerville. Approximately 1,700 corporate employees are making the move to the 13-story office complex this summer. Another 2,500 will relocate by early 2017.

Conference centers have capacity for up to 600 employees or community meetings, larger than any spaces in the previous portfolio.

“They didn’t necessarily feel a close connection to our larger mission and what we’re supporting,” Partners spokesman Rich Copp said. “The big thing is to bring people under one roof and foster a sense of collaboration.”

Few details were overlooked during the planning phase. Before the move, Partners surveyed employees on topics ranging from work styles to lunch habits and got an 87 percent response rate, Copp said. It used the feedback to inform architects’ designs for the 825,000-square-foot office complex. Employees indicated they plan to eat lunch outside the complex an average of twice a week, for example, which factored into the vendor requirements for the employee cafeteria.

Designed by lead architect Gensler, the complex puts a premium on energy efficiency. The building was laid out on the site with its long side facing south, to maximize the heat gain during the cold weather months. Wireless sensors mounted on windows measure the intensity of the sun’s rays, automatically raising or lowering window shades to optimize the efficiency of the heating and cooling system. Air ducts are embedded in the floor, giving employees the ability to adjust the air volume in their workstations. The complex will target LEED Gold certification.

While the massive floor plates span over an acre, a variety of uses break up the views. Some 328 phone rooms are available for private conversations, and another 205 “huddle rooms” can accommodate meetings of two to four employees.

Cubicle wall heights were capped at 50 inches to maximize natural light penetration to the core of the building, said Todd Dundon, a Gensler principal. Adjustable desks provide privacy in the seated position as well as a standing option.

A 2,000-space parking garage topped with a 1-megawatt solar array serves the complex topped but Partners expects a significant number of employees to commute using new MBTA Assembly Row station that opened in 2014. The company reimburses employees for 50 percent of their pre-tax contributions for monthly MBTA passes, up from 30 percent before the move.

Despite the cost of new construction and state-of-the-art amenities, annual real estate costs will be $10 million to $15 million below what Partners was paying for its leases. Partners has an option to add another 200,000 square feet.

Partners sold the 100,000-square-foot retail condo portion of its complex last week to Federal Realty Investment Trust, the master developer of Assembly Row, for $25.2 million.

The retail space on the first and second floors will include up to 14 tenants including Mike’s Pastry, a fitness club and various restaurants and shops. Additional tenants will be announced this fall, Federal Realty spokeswoman Andrea Simpson said.