J.M. Brennan is a mechanical contractor dedicated to providing high performance HVAC, Plumbing, Process Piping, Industrial Sh ... eet Metal, and Controls. We employ over 400 of the most highly skilled Steam Fitters, Refrigeration Fitters, Plumbers, and Sheet Metal Workers. We provide engineering, sustainable design, and service 24/7/365. Our customers include industrial, commercial, and healthcare facilities throughout Southeast Wisconsin. read more