fireplaces; fireplace inserts; safety barriers for fireplaces; heat exchangers; heat pumps and component parts thereof; heating appliances; heat recovery ventilators; electric control panels; electrical control systems for heating and air conditioning systems; electronic circuits; sound projectors and amplifiers; component parts for heating, ventilation and cooling (HVAC) systems; IoT (Internet of Things) controllers for furnaces and fireplaces; power supplies for machinery using heat exchang...