WDF Inc. (founded in 1929) is one of the plumbing, HVAC contracting and specialty general contracting companies. They have joined with Five Star Electric Corporation and Nagelbush Mechanical to form GreenStar Services Corporation as a diversified full service construction company.

WennSoft Inc. develops business software solutions that help HVACR companies manage labor-costs, schedule technicians and get invoices out quickly. Their inventory includes Service Management software for call management/dispatching, job costing software and project management software.

Wm. W. Meyer & Sons, Inc. are renowned manufacturers of commercial and industrial vacuums for cleaning ducts, boilers, furnaces and chimneys in residential, commercial, institutional and industrial applications.

Wrightsoft Corp. offer easy to use, drag-and-drop HVAC design and sales software that combines both residential and commercial loads, CAD-quality ducts, proposals and in-home sales tools.