Apparatus for space heating, ventilating and air conditioning; heating installations; furnace boilers; gas boilers for heating; heating boilers; heating boilers for household purposes; electric boilers; central heating boilers; water heaters; hot-water heating apparatus, namely, water heaters; hot water heating installations; gas burners; gas burning water heaters; gas burning space heaters; water heaters for household purposes; hot-air space heating apparatus; hot-water space heating apparatus; economizers, namely, devices for warming feed water in heating boilers; fuel economizers for heating boilers; hot water distributors of metal being hot water heating installations; hot water distributors, not of metal, being hot water heating installations; adapters being parts for heaters; feed water heaters; pipes for heating boilers; plumbing fittings, namely, drains; drain pans specially adapted for water heaters to protect from condensation, leaks, and overflow; thermostatic valves as parts of heating installations; dampers, namely, control devices used in air ducts to regulate the flow of air; heating elements; stoves being heating apparatus; heating panels used for indoor heating purposes; electrical heating cables; fabric air dispersion ducts for distributing and dispensing air as part of a HVAC system; air circulation kits consisting primarily of metal ducts and metal adaptors used to increase the amount of heat recovered from the fireplace using a blower or natural convection; system hot water distributors being hot water heating installations; thermostatic valves being parts of heating installations; automatic temperature regulators being thermostatic valves for central heating radiators; hot water tanks; hot-air space heating apparatus; hot-air heating apparatus; dosing valves being parts of heating or gas installations; heat accumulators; coils as parts of distilling, heating or cooling installations; air cooling apparatus; air circulation equipment, namely, electric fans, air conditioners and air handlers; air handlers; filters for air conditioning unit; air-conditioning, air cooling and ventilation installations and apparatus; water supply installations in the nature of devices for warming feed water in heating boilers; water supply installations, namely, faucets, water fountains, apparatus for filtering drinking water, and water purification installations; water filtration and purification apparatus; electrostatic water treatment apparatus; waste water treatment apparatus; air purifying apparatus and machines; safety accessories for gas pipes, namely, flashback arrestors and reverse flow check valves; electric heating water mats for household purposes in the nature of heating pads connected to portable electric boilers not for medical purposes; heat exchangers, other than parts of machines; heating systems composed primarily of tubes, pipes and manifolds through which warm or high temperature water circulates; furnace for household