Air conditioning contractor services; electrical repairs and installation of heating and air conditioning equipment; environmental services, namely, installation of environmentally compliant heating and air conditioning equipment; heating contractor services; heating equipment installation and repair; installation and repair of air conditioning apparatus; installation and repair of heating, ventilating and air conditioning equipment; installation and replacement service for heating, ventilating and air conditioning systems; intallation, repair and maintenance of heating equipment; maintenance and repair of heating installations; plumbing contractor services.