Cotti-Johnson HVAC has been providing superior heating and cooling installations and services in Massachusetts since 1948. Over that time we have had the opportunity to work with thousands of customers on projects ranging in size from a thermostat replacement to designing and installing mechanical systems for commercial and industrial buildings. Due to our commitment to quality and excellence we have forged partnerships with many national retailers including Costco and Lowes, as well as numerous utilities including National Grid, Columbia Gas and Mass Save.