Residential & Commercial Plumbing, Heating & Air Conditioning System Installation, Repair and Maintenance Services in Massachusetts. Gervais Mechanical is family owned and operated and provides the highest quality plumbing, heating and air conditioning products in tandem with state-of-the-art installation and first-in-class customer service. The Gervais Team specializes in oil/gas heating system installation, central air conditioning system installation/repair, ductless mini split installation and repair, boiler installation and replacement, water heater installation, repair and replacement as well as Commercial HVAC System Installation & Repair Services.