Commercial & Industrial


Comprehensive Energy Efficiency Treatment

Efficiency measures designed by OpTerra save the Colonnade hotel over $250,000 per year.

OpTerra provided a comprehensive energy conservation analysis of the Colonnade Hotel in Boston, Massachusetts that resulted in the identification and implementation of cost effective controls, lighting, chillers, and electrically commutated motor (ECM) technologies.


OpTerra replaced two of the existing water-cooled chillers with one 250-ton frictionless centrifugal chiller. Additionally, a refrigerant monitoring system, exhaust fan system, and automated control damper to provide fresh supply air to the mechanical room were installed. In the Colonnade’s 285 guest rooms and throughout the hallways, OpTerra replaced standard-efficiency motors in the fan coil units with ECM motors which use high-efficiency programmable brushless direct current (DC) motors. A new motor control card was installed in the fan coils that appropriately interfaces with the Inncom room temperature control system.

The existing Building Automation System (BAS) was replaced with a new system, complete with a computer-based front end with user-friendly interface for all the equipment tied to the existing BAS. The new BAS strategies included scheduling, set-back and optimum start/stop controls. The Colonnade’s Huntington Ballroom’s air handling units (AHU) were modified to accept return air. BAS controls were installed on the AHU’s existing outside air dampers and new return air dampers. Additionally, the BAS was programmed to set back these AHUs during unoccupied hours and to modulate the dampers to maintain room temperatures.

Chiller Diagram


OpTerra installed energy efficient lighting in various areas of the hotel including offices, the kitchen and the parking garage. LED technology was installed in guest bathrooms, ballrooms, and restaurant and lobby areas. In office areas around the hotel, occupancy sensors were installed in order to further decrease energy usage by switching off lights in unoccupied areas.

Energy efficiency measures designed and implemented by OpTerra provide cost savings to the Colonnade Hotel of over $250,000 per year.