Everyone knows the HVAC repairman fixes your heater or cooler. But what is HVAC?

HVAC stands for heating, ventilation, and air conditioning. HVAC is actually much broader and more complex than just your heater or air conditioner. It is responsible for making modern buildings habitable, in terms of thermal comfort in as well as the indoor air quality. For large facilities, HVAC design requires a team of engineers with skills in mechanical engineering, electrical engineering, fluid dynamics, and thermodynamics. For smaller projects, a contractor will select appropriate systems based on an evaluation of the building.

large HVAC system

HVAC – Heating

There are many different varieties of heating systems. They may be as simple as a fireplace or as complex as a system of pipes containing highly pressurized steam. The type of heater most of us are familiar with – in home central heating – uses a system of ducts to transport warm air into the various rooms of your house. It may burn natural gas to produce this heat, or they may do it by passing an electrical current through a high resistance wire. The heated air is then forced through your ducts by a fan.


Heating is certainly the most dangerous letter in HVAC. If your heating system uses combustion to generate its heat, then it also produces carbon monoxide and other dangerous combustion byproducts. Proper ventilation is necessary to prevent these toxic gasses from building up to dangerous levels. Another potential danger in combustion based heating systems in incomplete combustion. Incomplete combustion occurs when the heater is starved for oxygen, and causes carbon monoxide and other toxic gasses to be distributed alongside the warm air. If your heating system uses combustion to produce heat, you should have it inspected and serviced by a professional annually, and you must use carbon monoxide alarms to monitor for any buildup of the gas — don’t forget to change their batteries!

Check back soon for What is HVAC? — Part 2