A warm-air heating, ventilating and air-conditioning contractor fabricates, installs, maintains, services and repairs warm-air heating systems and water heating heat pumps, complete with warm-air appliances; ventilating systems complete with blowers and plenum chambers; air-conditioning systems complete with air-conditioning unit; and the ducts, registers, flues, humidity and thermostatic controls and air filters in connection with any of these systems. This classification shall include warm-air heating, ventilating and air-conditioning systems which utilize solar energy.
San Francisco is not just one of California’s great cities, but an international city known the world-over. San Francisco’s rare city-county combined government regulates a large number of industries and business-types including entertainment and anything that create environmental waste. Further, the regional Bay Area Air Quality Management District requires additional permits for businesses ranging from dry cleaners to auto mechanics. Of course, state and federal licensing rules also apply – making businesses in San Francisco among some of the most regulated. San Francisco's economy is bolstered by several major sectors including financial, shipping, high-tech, environmental and biotech. Although many major international companies have either headquarters or presence in San Francisco, the city works hard to help and foster the role of local entrepreneurs in the economy.