New home buyers are encouraged to have a qualified professional inspect the heating and cooling systems in a home as well as the ducts, vents, and internal parts of each system. For many San Francisco homeowners, air conditioners are irrelevant and in most cases not even present. Heating systems are essentially universal in SF homes. As with all expensive components of a home, a buyer or seller should assess the condition and quality of the heating/cooling system in relation to the price of the home. In most cases these systems will not impact the price dramatically (on a percentage basis at least) unless the system is in such poor condition and the home/building large enough as to require a substantial investment to replace it.