








Our Services and Divisions
Warner Mechanical
Warner Mechanical, a proud division of R.W. Warner, Inc., has served as a trusted provider of expert HVAC and plumbing services in Frederick, Maryland, and the surrounding region for over 88 years. We are built on a legacy of quality workmanship, dependable service, and long-standing relationships.


Kaempf & Harris
Kaempf & Harris Sheet Metal provides precision fabrication and expert installation in Frederick, MD, and the surrounding region. We specialize in high-quality, custom metal solutions for complex commercial, industrial, and institutional projects, from intricate HVAC ductwork to custom components. Our integrated service ensures seamless quality control from initial design through meticulous on-site installation.
Warner Construction
With over 88 years of legacy, Warner Construction provides expert commercial General Contracting and Construction Management services in Frederick, MD. We deliver high-quality, dependable construction solutions for diverse, complex projects, offering comprehensive oversight from conception to completion. Partner with us to bring your building vision to life successfully and efficiently.


Williams Electric
Williams Electric, a division of R.W. Warner, Inc., offers expert electrical contracting in Frederick, MD. Our licensed team handles commercial and industrial projects of any size. We provide comprehensive services from installations and repairs to panel upgrades, generators, and lighting, ensuring safe, reliable, and lasting performance for your power needs.
At R.W. Warner Inc., our mission is to deliver exceptional commercial construction projects with an unwavering commitment to quality control. Warner Quality strives to exceed client expectations by ensuring every project meets the highest standards of safety, precision, and excellence. Our dedicated team embraces a culture of continuous improvement, accountability, and collaboration, ensuring every detail is executed seamlessly from start to finish.
We are committed to fostering strong, long-lasting partnerships, maintaining transparent, proactive communication, and upholding our reputation for reliability, integrity, and superior craftsmanship in the construction industry.
Quality control training is a necessary commitment that we have created here at R.W. Warner Inc. Currently we have two full-time employees, Quality Control Manager and Quality Control Superintendent, that are responsible for coordinating quality phase meetings, ensuring proper installations, inspections and follow-up reports as needed. Quality Control training consists of but is not limited to:












