37 Furnace installation and repair; Heating equipment installation and repair; Home energy assessment services for the purpose of determining home improvements needed to improve energy use and efficiency; Installation and maintenance of photovoltaic installations; Installation and maintenance of solar energy based power plants; Installation and repair of air conditioning apparatus; Installation of building insulation; Installation of doors and windows; Installation of electrical and generating machinery; Installation of geothermal energy based power plants; Installation of insulating materials; Installation, repair and maintenance of condensing apparatus, steam condensers, radiators for motors and engines, air reheaters, boiler tubes; Installation, repair and maintenance of heating equipment; Repair and installation services, namely, the installation of heating, cooling and environmental control systems primarily using solar energy, renewable energy resources and rainwater