Westco Electrical & Equipment Corp. was established in 1990, by Engr. Rodolfo R. Peñalosa, PEE, PECE, APEC Engr., ACPE Engr., IIEE Fellow, CEM (Certified Energy Manager), who started the company in 1976 under the name, R. R. Penalosa Electrical & Communications, Inc. (RPEC) and in 1986-87, set up an electrical contracting company in Los Angeles, CA until 1990 with an electrical contracting license of C-10. He pursued the local company operations upon his return and in 1990, the RPEC corporate name was changed to Westco Electrical & Equipment Corp. The company's core expertise and operations in electrical design for commercial, industrial and large residential buildings, testing and commissioning, and electrical audits expanded to include sales engineering for test instruments used by utilities, power plants and industrial plants in the Philippines.

In September 2021, Westco was certified by the Department of Energy (DOE) as “Certified ESCO” for having evaluated, conducted and supplied energy saving solutions to prove energy savings. Westco has likewise conducted pre-testing and commissioning for new construction, new substations, post testing & commissioning and utilities and substation maintenance, and retroactive testing and commissioning for systems that have not been tested prior to operation. Westco has conducted evaluations related to power quality, power corrections with harmonics compensation, applying both passive and active filters, thermal imaging, on-line or condition based maintenance and recently, measurement and verification for energy audits of electro-mechanical systems, using a software for data-gathering and modelling for Level I, Level II and Level III energy audits.