Ever wonder where the cool refreshing feeling in the summer and warmth you feel in the winter time at your home or business comes from? The introduction of HVAC is the reason for this. We have been trying since the beginning of time to find an easier way to warm up or cool down. While we may take this for granted, it is important to know why we have this and how this system was developed. HVAC is the term referred to the heating, cooling and ventilation of air in both homes and buildings. Although there is no founding father of HVAC there have been many different people who have made a outstanding impact on this industry today. HVAC dates back many thousands of years. Many new constructions today require the uses of HVAC making this something many rely on today for the comfort of their homes. It’s important that people have a true understanding of how HVAC works and all terms involved in the process of this industry. A few of the many terms people tend to misunderstand when referring to HVAC is “Absorption and adsorption are two distinct HVAC-related terms that often get mixed up. Absorption is the internal process of taking up light, heat, or any other energy by molecules, while adsorption is the adherence of gases and liquids to each other on the surface”.(Source 2) With these terms and many other being a important part of “The development of modern air conditioning has allowed for advancements in medical technology, longer human life expectancy, reduction in the spread of diseases that were once very common and in warmer climates, dramatically increased employee productivity”(Source 1). The stable temperatures of these systems allow for the ease of keeping people happy and healthy. While this makes people happier and more efficient in the daily tasks studies show scientists have found people who live in an air conditioned environment loose some of their natural tolerance for heat making the need for HVAC systems more prominent and desired. Before air conditioning was common, many businesses and government offices took a summer vacation. The heat was to extreme to bear without circulating air. This is where HVAC has made a outstanding impact on today’s society. HVAC has been around for thousands of years, dating back to prehistoric times. Early central heating seems to have developed along several lines that included hearths and fireplaces, stoves, and underfloor systems. Fixed central hearths date as far back as 2500 B.C. They were excavated in Greece. Crude fireplace heating was used as early as the 800s A.D., and was widespread in Europe by the 13th century. The French were having problems with dirty contaminated air so miners created ventilation in the mines to allow fresh air down in the quarry when it was hard to breath. The first concept of air conditioning occurred around 500 years ago.”A small village in Persia built wind towers to try to get the same effect as air conditioning. These towers were rigged with wind scoops to catch prevailing breezes. Internal vanes circulated that air throughout the buildings while forcing hot air out” (Source 2). Many people have put their own touch on, this constructing it to what we now know as modern air conditioning and heating. Too many people household air conditioning and heating is a necessity; creating millions of jobs and businesses pertaining to HVAC; This has created a multi-million dollar industry. Some even believe that a good heated and air cooled home is just as important as the home itself. Comfort and the ability to control the temperature we life in is a desired feature many could not live without. Throughout existence mankind has always adapted to their surroundings. Throughout the ice age and prehistoric times they would produce fire from sticks and other tinder but, this has came a long way. As far back as the internet and books date back there has always been different interpretations of HVAC. During the early advancements of HVAC much of the fuel was wood and/or coal. “In 180 AD China, artisan Ding Huan invented a 10-foot wide rotary fan made of seven connected wheels. A single operator could power the device and cool an entire hall of people simply by turning a crank” (Source 2).Underfloor heating systems, the original radiant panel systems, seem to have first appeared in the Middle East. King Arzawa installed such a system in his palace at Beycesultan, Turkey, about 1300 B.C. It was said that “Leonardo Da Vinci built a water driven fan to ventilate his rooms to create ventilation during the summers heat”(Source 2). whether or not it’s true they say the roman empire perfected HVAC. “They would construct boilers or “fire rooms” where they would burn wood or coal. The heat from the fires was then transported throughout their building by using tunnels and underground passages. This would raise or lower the temperature to their specific needs.”(Source 2). Roman’s used to use something known as hypocaust (a central heating system which has furnace in the basement and flues to distribute heat (Source 2). It was also said that they would have small fires underneath their pools and spas also. In 1500’s France would construct ventilation machines used in their mines. “These machines used to have a series of fans with blades which used to direct fresh air into the shaft” (Source 2). During the 1600’s, the very first gravity exhaust ventilation system was made for the US House of the Parliament. “Benjamin Franklin invented the very first stove which is supposed to be known as the first steam heating system.”(Source 2) It wasn’t that great of an invention but, it did help start the modernization of HVAC. “The first record of the idea of air conditioning was attributed to British scientist Michael Faraday, who discovered in 1820 that by compressing and liquefying ammonia gas, one could chill an adjacent substance (such as air) when the ammonia was allowed to evaporate, paving the way for the modern air conditioner”.(Source 3) The very first steam-heating system installation was in England so the Governor of the Bank of England could grow grapes in the cool temperatures.(Source 2) like Benjamin Franklin a stove with a furnace for heating air was used in England. This arrangement had system of pipes which could heat up even big factories. This was the first looks at modernized HVAC, and it is still used today. “John Gorrie is considered the father of refrigeration and air conditioning. He was a doctor in Florida, and in 1842 developed a machine to make ice. He used this machine to cool down the air for his patients, making them much happier and he believed healthier.”(Source 2) “In 1842 the law of conservation of energy is discovered(Energy can neither be created nor destroyed; rather, it transforms from one form to another). The first and second laws of thermodynamics were made(The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases). Laws of gases were discovered and widely put to use(The gas laws were developed at the end of the 18th century, when scientists began to realize that relationships between the pressure, volume and temperature of a sample of gas could be obtained which would hold to a good approximation for all gases).”(Source 2) During this time they discovered that if liquids vaporized it could cool and warm a structure depending on the substance. “In 1886, Schuyler Wheeler invented the electric fan, which was the most popular way for Americans to cool down until the end of WWII.” (Source 2) The evolution of HVAC really starts to pick up in the late 1800’s throughout early 1900’s. Much of how we know modern HVAC came from this era. In 1903, the New York Stock Exchange building in New York City was one of the first structures to use an air conditioning system.; this is one of the most important breakthroughs for HVAC. One of the best inventions was a “furnace system with centrifugal fans. It was a high pressure steam heating systems with, massive fan systems and high speed centrifugal fans and axial flow fans with small electric motors.” (Source 1) This was the base of mordenized HVAC or as we call it, central air conditioning. Soon every business had to have this. “Every industry has its own golden standard, and the HVAC world is no different. The Air Standard, as we call it, means that air must be 68 F (20 C) with a 36% relative humidity at 14.7 psia (pounds per square inch absolute).” (Source 2) The development of air conditioning was one of the biggest boosts to the movie industry, as movie theaters could get very uncomfortable in warm summer months.”(source 2) Many say this is what saved hollywood. “Packard was the first automobile manufacturing company to incorporate air conditioning in their cars in 1936.” (Source 2) Soon after all vehicles have air conditioning. HVAC was changing the life of everyone, making life better and more comfortable. You could now sit at home on a hot summer day and your home is a cool 68 degrees fahrenheit, or have a warm house in the winter. “Air conditioner sales took off in the 1950s. By 1953, more than one million room air conditioner units had been sold. 35 years later, in 1998, more than 6.2 million air conditioners / heat pumps were shipped to homes and businesses.”(Source ) The amount of energy the United States uses each year to power air conditioning units is about the same amount of energy consumed by the entire continent of Africa. HVAC has been around for thousands of years, dating back to prehistoric times. We have been trying since the beginning of time to find an easier way to warm up or cool down. While we may take this for granted, it is important to know why we have this and how this system was developed. Many people have put their own touch on, this constructing it to what we now know as modern air conditioning and heating. The stable temperatures of these systems allow for the ease of keeping people happy and healthy. “The development of modern air conditioning has allowed for advancements in medical technology, longer human life expectancy, reduction in the spread of diseases that were once very common and in warmer climates, dramatically increased employee productivity”(Source 1). Too many people households air conditioning and heating is a necessity; creating millions of jobs and businesses that pertaining to HVAC. The evolution of HVAC really starts to pick up in the late 1800’s throughout early 1900’s. Much of how we know modern HVAC came from this era. HVAC was changing the life of everyone, making life better and more comfortable. You could now sit at home on a hot summer day and your home is a cool 68 degrees fahrenheit, or have a warm house in the winter. Before air conditioning was common, many businesses and government offices took a summer vacation. The heat was to extreme to bear without circulating air. This is where HVAC has made a outstanding impact on today’s society. Some even believe that a good heated and air cooled home is just as important as the home itself. Comfort and ability to control the temperature we feel is a desired feature. HVAC is only going to grow with increase of population, opening up many new jobs for generations to come.In conclusion, HVAC is one of the comforts of modern life we have come to think of as a necessity for our personal comfort and health. This has lead to the HVAC being one of the leading industries. HVAC is used in homes, vehicles, boats, offices, warehouses and industrial plants . With many of today’s new constructions being required to have HVAC ,This industry is growing rapidly with today’s technically and times today. The next time you come in from the heat or snuggle up in your 70 degree home while it’s freezing outside you can thank the industrious people who helped HVAC evolve over time as well as the technicians who keep our HVAC units working. Without HVAC our life would have been a lot different and a lot less comfortable .