Grunau Company

Grunau Company operates as a mechanical systems contractor based in Oak Creek, Wisconsin, within the greater Milwaukee metropolitan area. The business holds a 3.2-star rating derived from 13 customer reviews, reflecting a mixed client experience. Service operations extend across southern Wisconsin, covering communities from Madison westward to Green Bay northward, with additional project work spanning multiple states. Grunau functions as a union contractor affiliated with APi Group and maintains continuous availability with 24/7 emergency service capability throughout all operating days.

The contractor distinguishes itself through integrated project delivery methodologies and building information modeling capabilities, enabling collaborative planning from initial concept through final commissioning. Their portfolio encompasses mechanical systems engineering encompassing HVAC, plumbing, process piping, electrical infrastructure, refrigeration, and underground site utilities. The organization maintains in-house sheet metal fabrication and a dedicated pipe and weld shop, allowing for specialized custom component fabrication rather than outsourcing critical manufacturing phases. Their operational philosophy incorporates lean construction principles and safety culture frameworks, positioning the business for commercial and industrial projects requiring coordinated multi-trade mechanical systems installation.

Customer feedback reveals polarized service experiences. One reviewer documented an interaction involving a company driver in Kansasville that they characterized as unprofessional, while another detailed a same-day service scenario where the team arrived promptly during a critical heating or cooling emergency. Positive reviews specifically reference knowledgeable and helpful technicians who delivered quality workmanship, with Sandy Rapant noting the company's dependability and Greg Luna describing the staff as friendly and accommodating. These accounts suggest service quality may vary by specific job scope and assigned technician.