- AFUE (Annual Fuel Utilization Efficiency): AFUE is a rating for how efficient your gas furnace runs. A higher AFUE means a more efficient furnace. Federal law requires that any residential furnace constructed after 1992 operate with at least an AFUE of 78 percent. Older furnaces run at around 60 percent AFUE on average. For homeowners with older and less efficient furnaces, it could be a beneficial time to install a new and high-efficient unit.
- ARI (Air Conditioning and Refrigeration Institute): ARI is a non-profit HVAC organization whose purpose is to regulate industry quality. ARI releases ratings standards for testing cooling and heating products.
- BTU (British Thermal Unit): A BTU is a unit for the amount of heat required to raise or lower the temperature of one pound of water by one degree Fahrenheit.
- BTUH (British Thermal Units per Hour): The rate of heat transfer for heating and cooling systems is measured in BTUHs.
Capacity: Normally measured in tons or BTUs, a unit’s capacity refers to its ability to heat or cool a specified area. - CFM (Cubic Feet per Minute): CFM is a measurement for volume of air movement. The larger the CFM the more air a blower or fan can move per minute.
- Compressor: Compressors are a critical component in the cooling process as they pump refrigerant through the coil allowing heat to be transferred and then released to the outside air
- Condenser: Also known as the outdoor coil, a condenser dissipates heat to the outdoors. When a heat pump is used in heating mode, this role is switched.
- COP (Coefficient of Performance): COP, or CP, is used to determine the electrical efficiency of a heat pump. ARI designates the COP at 47 degrees (F) and 17 degrees (F).
- dB (Decibel): Decibels measure the loudness of a sound, and are sometimes used to communicate the noise level of HVAC equipment.
- DOE (Department of Energy): The DOE is a federal agency that tracks the consumption of resources and energy and sets standards for HVAC efficiency.
- Downflow: This refers to the direction of air movement that some furnaces use. In a downflow furnace, cold air enters from the top and is then heated and emitted from the bottom of the furnace. This heated air is then sent to throughout the house where it will naturally rise and heat each room.
- Ducts: These are the pipes through which heated or cooled air flows into each room. They are large in diameter and made to conserve energy. Ductwork is a term referring to your home’s duct system as a whole.
- EER (Energy Efficiency Ratio): EER is the ratio of an AC unit’s cooling capacity in BTUs per hour/wattage. A higher EER signifies higher efficiency.
- Efficiency: A general term used to describe how much input energy (what you pay for) is turned into useable output energy (the change in temperature you feel). The higher-efficiency a HVAC unit the less costly it is to operate.
- Evaporator Coil/Evaporator: Another important component of your heat pump and AC system. As warm air travels over a refrigerant-filled coil, the refrigerant evaporates absorbing heat from the air in the process. The ensuing gas refrigerant is then pumped to the outdoor coil, which emits heat into the air and converts the refrigerant back into a liquid.
- Heat Exchanger: As the name suggests, this component transfers heat from furnace burners to your system’s blower.
- HOR Flow (Horizontal Flow): Another direction of airflow a furnace can use. An HOR flow furnace receives air at one end and delivers air on the other end at the same height.*
- HSPF (Heating Seasonal Performance Factor): HSPF measures the heating efficiency of a heat pump. According to the Department of Energy, the minimum HSPF should be 6.8.
- Humidifier: This optional accessory for HVAC systems injects water vapor into dry, heated furnace air. In doing so it increases energy efficiency because moist air can carry more energy. It also improves the comfort of your home and prevents upper respiratory dryness.
- HVAC (Heating, Ventilating & Air Conditioning): This term is a catch-all for heating and air conditioning manufacturers and contractors and is the name of the industry as a whole.
- Indoor Coils: Split-systems use indoor coils to transfer heat from inside the home to outside or vise versa. Modern systems are designed to be more efficient when the indoor unit, consisting of a blower and coils, is suitably matched with the outdoor unit, consisting of a heat pump or air conditioner. This is why it is best to replace both indoor and outdoor units at the same time.
- kW (Kilowatts): The unit is equivalent to 1,000 Watts. A kW per hour is used when an HVAC unit uses 1,000 Watts in 1 hour, and is then given an energy rating of 1 kWh.
- Package Unit: The cabinet that holds all HVAC components in one place. They are normally installed on top of or on the side of a home or commercial facility.
- Refrigerant: A liquid chemical that is used to absorb and transfer heat from one area of an HVAC system to another.
- Refrigerant lines: Small copper pipes that transfer liquid refrigerant between indoor and outdoor cooling units.
- SEER (Seasonal Energy Efficiency Rating): The SEER is used to denote a heat pump (in cooling mode) or air conditioning unit’s efficiency. The Department of Energy SEER requires a minimum rating of 10. Higher SEER ratings are more efficient and desirable.
- Split System: Home comfort systems that use indoor and outdoor units to deliver climate-controlled air.
- SRN (Sound Rating Number): The Air Conditioning and Refrigeration Institute runs tests on HVAC units to assign it an SRN so that customers can know how loud their units will be. Average SRNs are between 74dB and 80dB.
- Thermostat: This device monitors and controls the temperature of a home. Programmable thermostats are more energy-efficient because they can allow a home to not be heated or cooled when residents are away.
- Ton: In the HVAC world, a ton is equal to 12,000 BTUs. Most home systems use equipment with a capacity of 1.5 to 2 tons.
- Upflow: The third direction of airflow a furnace can use. In these, air enters through the bottoms of the furnace and naturally rises as it is heated and then is pushed throughout the rest of the home.
- W (Watt): Measurement of electrical power. A 60W bulb uses 60 Watts of electrical power. Watts are named after a chemist and engineer James Watt, and therefore the term is uppercased.
- Zone: Your house may be divided into various heating or cooling areas. These are called zones.
