While air conditioning now seems like a necessity versus a luxury, two-hundred years ago it was only available for the high class. Through amazing technological breakthroughs, the modern HVAC system is now available worldwide. The earliest HVAC design comes from the 1840s when Physician Dr. John Gorrie came up with the idea to use ice to cool down hospitals. It failed, however, due to lack of funding. In 1932, H.H. Schultz and J.Q. Sherman changed this with the invention of an air conditioning unit that could fit on windows. This made it possible for homes to install central air conditioning and enjoy comfortable indoor environments.
When did modern HVAC systems begin to be installed in the majority of homes in the US?
By the 1960s, most new homes in the United States were built with central air conditioning. By then, electric air conditioner window units were affordable and had come down in price from the early days; for example, a 1938 Chrysler unit cost $416. By 2009, the Energy Information Administration reported that 87 percent of all American households—about 100 million homes—used AC units.
Are there any areas of the US where HVAC systems are not commonly found on all homes?
Regional differences are apparent in air conditioning usage. Southern households are almost twice as likely to use their central and room air conditioning equipment all summer as those in other regions. Homes in the South are also least likely to have a programmable thermostat connected to the central air conditioner, while homes in the West are most likely. Programmable thermostats are designed to reduce consumption by automatically and routinely cycling down the unit when more intensive cooling is not needed. Consumers could reduce overall cooling costs by installing and setting a programmable thermostat. About a third of households below the poverty line use room air conditioning compared to 15% of households with an income above $100,000. In contrast, about 75% of households with incomes above $100,000 use central air conditioning compared to just 44% of households below the poverty line. The share of room air conditioners continues to drop as more households, especially higher income and owner occupied households, choose central air conditioning equipment.