The heating, ventilation and air conditioning (HVAC) industry has been working to boost building comfort for centuries. What HVAC contractors know today is that the right system needs to be customized to meet a building's needs in terms of size, type, and configuration. The air conditioner is considered to be one of the most important inventions of modern times, creating comfort in homes and enabling functionality in hospitals, laboratories, data centers and myriad other public spaces. Outfitting a space with the appropriate unit can yield years of comfort.