HVAC or Heating, Ventilation, and Air Conditioning is an overall term used for the equipment and processes that heat and cool a space and help maintain good indoor air quality. Understanding the terms associated with an HVAC system will help you know a little more about them when it comes time to purchase a new one.
HVAC Dictionary Terms & Definitions
• ACH (Air Changes Per Hour) – This term is used to tell you the number of times per hour a room is supplied with or removed of air. This addition or removal of air is done though mechanical and natural ventilation.
• AFUE (Annual Fuel Efficiency Ratio) – This is similar to SEER (Seasonal Energy Efficiency Ratio. AFUE measures the energy efficiency of your heating system. It tells you how much of your fuel is used to heat your home and how much of the heat is lost during the process. For example, if a furnace has an AFUE rating of 90%, it means that 90% is turned into heat while the other 10% is lost through exhaust. If you have a furnace with an AFUE taking below 80%, consider having it replaced.
• Blower. Another name for the fan that moves cooled air through the ductwork.
• BTU (British Thermal Unit) – This is a measurement of energy used to indicate the rate of cooling, dehumidifying, or heating in an HVAC system. One BTU is the amount of energy that is needed to raise the temperature of one pound of pure water by one degree Fahrenheit.
• Coil. Pipes or tubes that carry refrigerant and where the heat exchange the produces cooling occurs.
• Ductwork. This is a system of metal pipes that extend from the air conditioning unit to the points through your home. They can be made of round or rectangular metal segments that are fastened tightly together. This ductwork carries all of the cool air created by your air conditioner.
• Evaporator. A coil where refrigerant changes from a liquid state to a gas state and absorbs heat.
• SEER (Seasonal Energy Efficiency Ratio) – This measures the energy efficiency of an air conditioning system. It measures the total cooling of your air conditioner or heat pump in BTUs compared with energy output used in the same period. Air conditioners with higher SEER ratings are more energy efficient and cost less to run.
Air Filter Ratings
Air filters are an important part of your HVAC system. Filters remove particulates like dirt, pollen and fibers so they don’t end up in your home. MERV (Minimum Efficiency Reporting Value) is a measure of the effectiveness of an air filter at removing particulates and other contaminates from your indoor air. Average filters have a MERV rating of around 6 to 8, while high-performance filters can have a MERV rating of 12 to 16. The most efficient filters have MERV ratings of 17 to 20.