24/7 EMERGENCY SERVICE: (209) 466-1477

J.H. Simpson Company’s Commercial division can provide mechanical services for all phases of construction, from preliminary cost analysis, mechanical system design, CAD drafting, fabrication, construction, installation, start-up, balancing and follow-up service. This “single source” capability lends significant value on any project.

System Design

A competent and well trained staff of designers and engineers, headed by Bill Relf, a California Registered Professional Mechanical Engineer, provides Design-Build services for the HVAC requirements for any type of application. more»

Sheet Metal Fabrication

J.H. Simpson Company has been involved in many types of sheet metal work, both in the fabrication and installation of various applications. The types of fabrication range from special purpose ductwork for the United States Navy aboard ships, to the radius gutter on the entry to the Hutchins Street Square Auditorium in Lodi, California.


Ranging from the smallest project to the largest commercial project J.H. Simpson Company is a leading HVAC installation contractor. We supply the HVAC needs of many churches and synagogues, markets and restaurants, retail stores, schools, office buildings and health facilities in Northern California.

Testing/ Balancing/ Duct Repairs

Our certified technicians will assure you that you’re getting the optimum performance from your system by providing:

  • Assurances that the system is working properly and documented in a written report
  • Adequate airflow and delivery of the proper amount of air to each room
  • The absence of duct leakage
  • Equipment and systems that function as per design criteria by the manufacturer, engineers and contractors


To make an appointment please call (209) 466-1477 or fill out the form below. Someone from J.H. Simpson Company will respond on the day that your email is received.


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