37 Installation, repair, maintenance, relating to water heaters, heating, space conditioning, ventilation and air conditioning systems and equipment, namely, furnaces, heat exchangers, boilers, heat pumps, dehumidifiers, humidifiers, air conditioners, air conditioning units, ventilating fans, air units, namely, heating units and furnaces for the exterior and/or top of buildings which replace exhausted heated air with a combination of heated and fresh air, hydronic heaters and accessories, and air conditioning chillers for home, commercial or industrial use, fireplaces, barbeques, solar power-generating equipment, emergency power generators, water conditioning equipment, swimming pool heaters, electric storage batteries, blast chillers for commercial food preparation and storage and patio heaters, all of the above sourced by gas, electric or propane; installation, repair, maintenance, of solar heating panels, solar water heaters, solar collectorsInstallation, repair, maintenance, relating to water heaters, heating, space conditioning, ventilation and air conditioning systems and equipment, namely, furnaces, heat exchangers, boilers, heat pumps, dehumidifiers, humidifiers, air conditioners, air conditioning units, ventilating fans, air units, namely, heating units and furnaces for the exterior and/or top of buildings which replace exhausted heated air with a combination of heated and fresh air, hydronic heaters and accessories, and air conditioning chillers for home, commercial or industrial use, fireplaces, barbeques, solar power-generating equipment, emergency power generators, water conditioning equipment, swimming pool heaters, electric storage batteries, blast chillers for commercial food preparation and storage and patio heaters, all of the above sourced by gas, electric or propane; installation, repair, maintenance, of solar heating panels, solar water heaters, solar collectors