maintenance and repair of heating and air conditioning systems, namely, duct cleaning, [ pipe cleaning, ] drain cleaning, [ pipe unclogging, sewer unclogging, leak repair, fixture repair; ] maintenance and repair of electric and gas appliances, namely, furnaces, boilers, air conditioners, gas fireplaces, [ air cleaners, humidifiers, dehumidifiers, ] water heaters, ranges, ovens, [ microwave ovens, ] grills, [ fans, ] refrigerators, freezers, dishwashers, [ garbage disposals, ] washers, dryers, space heaters