- Advent Environmental, Inc
- Ahern Painting
- Alliance Express
- Arbella Insurance, Inc.
- Archdiocese of Boston
- Arlmont Fuel
- Asset Management Specialist
- AT&T
- Atlantic Heating and Air Conditioning
- Atlantic Packaging
- Automatic Temperature Control Corp
- Bay State Fuel Corp.
- Beth Israel Hospital
- Bigelow Oil
- Biogen
- Bose Corporation
- Bostik, Inc.
- Boston College
- Boston Fire Department
- Boston Housing Authority
- Boston University
- Boucher Energy
- Bremis Realtors
- Cabral Plumbing
- Cape Cod Potato Chips
- Catania-Spagna Corp.
- Century 21
- Citizens Energy
- City of Lynn
- City of Newton
- City of Revere
- City of Somerville
- Coldwell Banker Hunneman & Co
- Commonwealth Gas Co.
- Community Builders
- Condyne Advantage
- Cooperative Living of Newton
- Dana Farber
- DEC-TAM
- Devaney Fuel Corp.
- DeWolfe New England
- Drill Construction
- Dunkin Donuts
- Eastern Bank
- Eastern Propane
- ElecComm Power Services, Inc.
- Emcor
- ERA Real Estate
- Executive Plumbing, Heating & Contracting
- Faulkner Fuel
- Fawcett Oil
- FedEx Express Ship Center
- First Eastern Mortgage Corp
- General Dynamics
- Gillette Stadium
- Great Lowell Community Action Program
- Green Cab
- Griffin Fuel Corp
- Grubb and Ellis Company
- Hammond Residential Real Estate
- Hanscom Air Force Base
- Harrington and Sons
- Harvard University
- Herb Chambers
- Holden Oil
- Holliston Oil
- IBM
- Industrial Tool Repair
- Johnson Controls Worldwide Services
- Joslin Diabetes Center
- K & N Oil Service
- Keyspan
- Kraft Power
- LVI Environmental Services
- Madico, Inc.
- Mainstream Mechanical
- Marchand Oil
- Marlboro Hospital
- Massachusetts Bureau of State Office Buildings
- Massachusetts Water Resource Authority (MWRA)
- Massachusetts Army National Guard
- Massachusetts Institute of Technology
- Mass Energy Consumer Alliance
- MBTA
- Millipore Corporation
- Milton Cat
- Mitre Corporation
- Modern Dispersions, Inc.
- Morgan Linen Services
- Mount Auburn Hospital
- Munhall Fuel
- National Aviation Academy
- National Grid
- National Oceanic and Atmospheric Administration (NOAA)
- New England Casket
- New Hampshire Fish and Game
- NextEra Energy Resources, LLC
- Northern Utilities
- Patrick J. Kennedy & Sons, Inc.
- Piantedosi Baking Compan
- Pinehurst Properties
- Plumbing Unlimited
- Port Oil
- Prudential Real Estate
- Public Service of New Hampshire (PSNH)
- Radisson Hotel Providence Harbor
- Raymond Company
- Raytheon
- RE/MAX
- Reebok International Limited
- Regis College
- SAK Environmental LLC
- Simmons College
- Simonds International
- Somerville Housing Authority
- Sprint Nextel Corporation
- Suffolk University
- Sunoco
- Texaco
- The Beal Companies, LLP
- The Procaccianti Group
- Town Of Concord, Ma
- Town of Westford, Ma
- Trammell Crow Co.
- UMASS Dartmouth
- Unified Mechanical Inc.
- UPS
- VA Medical Center
- Veryfine Products, Inc.
- Vestex Corp.
- Vining Disposal
- Walsh Corp.
- Wayne & Co.
- Weston and Sampson
- Wilson Farm
- Wise Construction
- y, Inc.
