Richard Trethewey

Richard Trethewey is a plumbing and heating expert recognized as the resident mechanical systems specialist on the home improvement series "This Old House." A licensed master plumber and leader in the HVAC industry, Trethewey has provided professional insight on plumbing, heating, and cooling to a wide audience through his work on "This Old House," "Ask This Old House," and related television projects. His on-camera explanations and job-site demonstrations have clarified complex building systems for homeowners and tradespeople, establishing Trethewey as a trusted authority in residential mechanical systems.

Trethewey’s television career is rooted in his real-world expertise. As a second-generation plumbing and heating professional, he joined "This Old House" in its early seasons and became the primary voice on topics such as hydronic heating, high-efficiency boilers, modern plumbing layouts, and energy-saving retrofits. Trethewey has also appeared on other home improvement networks and specials, and his practical teaching style has made him a regular presence at trade events, industry showcases, and live demonstrations, where he educates audiences on evolving codes, technologies, and best practices in the plumbing and HVAC fields.

Beyond television, Trethewey is an industry leader and entrepreneur. He has served as a principal in mechanical contracting and consulting ventures, including firms specializing in advanced heating, cooling, and renewable-energy-based comfort systems for residential and light commercial buildings. Through this work, Trethewey has advocated for high-efficiency equipment, thoughtful system design, and whole-house performance, contributing to the advancement of sustainable and comfortable solutions in the trades. His field experience and ability to communicate technical concepts under the demands of television production have made him a sought-after presenter for manufacturers, trade associations, and professional education programs.

Throughout his career, Trethewey has guided audiences through significant changes in building technology, including the shift from outdated systems to condensing boilers, sophisticated controls, and integrated mechanical designs. He has addressed the challenges of retrofitting new systems into older or historically sensitive homes and has used his platform to highlight the importance of skilled trades and craftsmanship. Trethewey’s technical competence, problem-solving skills, and approachable on-screen presence have influenced how viewers understand plumbing and heating, reinforcing his role as a credible voice in building systems and home comfort.