Many people assume that HVAC is complex and confusing because they hear HVAC experts using long words and mysterious acronyms. However, the reality is that understanding HVAC can actually be quite simple. Once you know a few basic terms, it is easy to follow what technicians are saying and make smart decisions for your property.


AFUE stands for annual fuel efficiency ratio. This measurement tells you how energy efficient your heating system is in one simple percentage. An AFUE of 70% would mean that 70% of your fuel is directly converted into heat while 30% of your fuel is converted into the exhaust. A higher AFUE means more energy efficiency and fuel savings.

Air Flow

When people talk about airflow, they are discussing how much air a duct system can move around a house. Airflow is measured in cfm/ton which stands for the amount of air in cubic feet moved per minute for each ton of a system’s capacity. Typically, a rate of around 350 cfm/ton is good in humid areas, while around 500 cfm/ton is ideal for dryer areas. To increase airflow rates, it is normally necessary to run more fans or remove any obstructions in the ducts.

Air Handler

When a technician is talking about your air handler, they are basically just talking about the big AC box inside your home. In a traditional split central air system, the air handler contains a blower and some of the smaller heating and cooling components.

Compressor and Condenser

This is the big noisy part of your AC. In most homes, it will be situated outside the home in a large box. In most traditional systems, the compressor and the condenser are always located next to each other. Their similar names and location mean that they frequently get confused for each other. They do slightly different jobs, but the main thing you need to know is that they work together to cool air. The compressor squeezes refrigerant gas to make it denser, and then the condenser changes the gas into a super-cold liquid.


Your ducts are the “veins” of your HVAC system. They transport hot and cold air throughout the home, so each room is evenly heated and cooled. Ducts can be made from steel, aluminum, or even plastic. Most ductwork runs through your attic, walls, or basement, so it is not visible. However, leaks in ducts can keep your system from functioning properly.


This is another acronym used for talking about how well a system adjusts air temperatures in your home. It stands for energy efficiency ratio and is used for discussing cooling machinery. The EER is calculated by comparing the cooling capacity to the power input for a system. Think of EER as being like the gas mileage in a car. A higher EER is always better because it means you pay less in energy. Another very similar HVAC term is the SEER or seasonal energy efficiency ratio. It measures the EER for an entire season, taking into account how your AC turns on and off as temperatures change each day. SEER can give an even clearer picture of how well an AC system works.

Heat Pump

Most HVAC systems either heat or cool air. A heat pump is a unique type of system that does both. It works by transferring heat as needed. In the winter, heat is transferred inside. In the summer, heat is transferred outside.


HVAC stands for heating, ventilation, and air conditioning. It is used as a sort of catch-all term that refers to just about anything involving the quality of your indoor air. Things that warm, cool, ventilate, or purify your air are usually considered HVAC components.

Intake Vent

The intake refers to the non-treated air that your system pulls into the machinery. You will typically have a fresh air intake that pulls in air from outside the home. You will also have a large intake vent near your air handler that pulls treated air into your system to heat or cool it even more. This vent is also called a return because it returns excess air to the air handler.

Load Calculation

This term is used when a company is trying to design an HVAC system for your property. It looks at all the heat property gains or losses. A load calculation takes into account heat leaking out from ducts, walls, and windows, and it also considers heat added from appliances, people, and sunshine. This helps you determine how big of an AC or heater you need.


The North American Technician Excellence organization provides certifications for HVAC technicians. A NATE-certified technician is guaranteed to have up-to-date training and meet rigorous standards to give you peace of mind.


OAT stands for outside air temperature. As the name implies, this is simply the temperature outside a building. Technicians often need to know the OAT to ensure that your system is running as efficiently as possible.


This is the chemical that makes any air conditioner and some heat pumps function. Refrigerant can be a liquid or a gas depending on its temperature. It helps to transfer hot and cold temperatures to their desired location. Refrigerant is sealed away inside your system. It is not safe to handle, so only trained technicians should work with it.

Supply Vent

The supply vent is the vent that supplies you with treated air. When your AC runs, cold air will come out of this vent. When your heat runs, the air will feel hot. Typically, you will have several small supply vents all over your home.


The thermostat is the small unit, typically mounted on a wall, that controls your HVAC systems. At their most basic level, thermostats let you set the desired temperature, and then they will run your system until it reaches that temperature. Modern, “smart” thermostats may also include software that adjusts running times to improve energy efficiency.


When people talk about tons in reference to HVAC systems, they are not discussing the actual weight of the system. Instead, it is discussing the amount of heat a system can remove or add to your home in an hour. A ton is always 12,000 BTU. A British Thermal Unit (BTU) refers to the amount of heat needed to change a pound of water by one degree. This measurement is very small, so when discussing HVAC, it is easier to refer to tons instead. Most homes need a system with about 1 ton of capacity per 600 square feet.

At Summit Heating, A/C, Plumbing & Electrical, we are always happy to educate our clients about HVAC systems. When you work with us, feel free to ask questions and get more information on HVAC terms. Our team provides HVAC services throughout the Denver Metro area. You can use us for repairs, maintenance, and installation on all sorts of furnaces, heat pumps, and air conditioners. We also provide air quality and water heater services. To schedule your next appointment with us, go ahead and give us a call now.

company icon
Categories: ,