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HVAC Terms You Need to Know

Whether you are a seasoned veteran of the HVAC business, or just learning the ropes, it’s always a good idea to have a working knowledge of some of our key industry terms. Take a moment to read over this list and make sure you are as prepared as you can be when the time comes to have work done at your house or business.

SEER: Seasonal Energy Efficiency Ratio –each air conditioner and heat pump receives a SEER rating, ranging from 13 to 20. The higher the rating, the more energy efficient the HVAC unit operates

Evaporative Cooler: The part of an air conditioner or heat pump that absorbs heat. In an air conditioner, the heat is pushed outside. In a heat pump, the heat is used to heat the home.

Ductwork: Air flows through this type of system so that it can be distributed through a home.

BTU: British Thermal Unit –one BTU equals one unit of heat energy. It takes one BTU to raise one pound of water one degree. When a heating unit has a high BTU, this means it has a high heating capacity.

Carbon Monoxide: When carbon burns in a home without sufficient amounts of air, an odorless and poisonous gas known as carbon monoxide will be released.

Compressor: This is the part of an HVAC unit that pumps refrigerant so that cooling requirements can be met and maintained.

Condenser: Part of the air conditioning unit that gets rid of heat. This is most often located outside.

Evaporator: This part of an air conditioning unit captures heat and removes it from the part of the unit that needs to be cooled. This is most often located above or below your furnace. Hence the upflow/downflow term.

Furnace: A device used in homes to put out heat. It can come as a single unit or be combined with an air conditioning unit, commonly referred to as a central heating and cooling unit. Everyone loves a good furnace!

Geothermal heat pump
: A type of central heating and cooling unit that takes heat from the ground and uses it to heat a home. This can be a very efficient way to heat your home however can require the most amount of money to retrofit.

HVAC: Heating, Ventilation, and Air Conditioning –a unit used in a home to heat and cool the inside.

MERV Rating: Minimum Efficiency Reporting Value –Filters have MERV ratings, which describes how big the holes are in the filters. A higher MERV rating means the smaller the holes, which translates into higher efficiency.

Refrigerant: A liquid/chemical that’s used in cooling units; this chemical gives off a cooling effect, and it is commonly referred to as Freon.

Split System: When a home has a HVAC unit that has components located both inside and outside of the home, this is known as a split system.

Ton: A unit of measurement that is used to identify the cooling capacity of an air conditioning unit. Here’s a nifty tip- 12,000 btu’s equals 1 ton. And we need approximately 400 CFM per ton. So a 3-ton system is equivalent to 36,000 btu’s and will need about 1200 CFM for proper airflow.

Ventilator: Part of the HVAC system that ventilates the home.

Zoning: This is a method used in homes when different rooms require different comfort zones. Zoning provides enhanced heating and cooling, which translates into optimal comfort and efficiency. Imagine being able to turn certain parts of the house “on” while turning other parts “off”. All separate from one another.

While some of these terms might be new to you, we at Spencer Air Conditioning and Heating have been experts in the industry for over 56 years! Let us put our expertise and knowledge to the test. Contact us day or night at 972-446-COOL (2665) or visit online at if you have any questions or concerns about your HVAC unit.