HVAC & Air Conditioning Glossary - AC Terms Explained | Forney HVAC Pros

Air Conditioning & HVAC Glossary

Welcome to the HVAC glossary from Forney HVAC Pros. Whether you're shopping for a new air conditioner, troubleshooting your furnace, or just trying to understand your energy bill, knowing these common HVAC terms helps you make informed decisions about your home's heating, ventilation, and air conditioning system.

We've compiled this list of the most important HVAC definitions for homeowners in Forney and the surrounding areas.

A

AC (Air Conditioner)

Short for air conditioner or air conditioning. A system that removes heat and humidity from indoor air to cool your home. Common types include central air conditioners, window units, and ductless mini-splits.

Air Conditioner

A cooling system that extracts heat from indoor air and releases it outside, lowering the temperature in your home. Works by circulating refrigerant through coils to absorb and transfer heat.

AC Unit

The complete air conditioning system, typically consisting of an outdoor condenser unit and indoor evaporator/air handler. In split systems, these two units work together to cool your home.

AFUE

(Annual Fuel Utilization Efficiency) A percentage rating that measures how efficiently a furnace or boiler converts fuel into heat over a year. Higher AFUE (e.g., 95%+) means lower energy bills. Look for high-AFUE furnaces for better heating efficiency in Texas winters.

Air Handler

The indoor component of a split HVAC system (often in the attic or closet) that contains the blower fan and evaporator coil. It circulates conditioned air through your home's ductwork.

Airflow

(CFM - Cubic Feet per Minute) Measures how much air your HVAC system moves. Proper CFM ensures even cooling/heating and good indoor air quality.

Air Filter

Traps dust and debris; regular replacement prevents system strain and improves air quality.

B

BTU (British Thermal Unit)

A unit of heat energy used to measure air conditioner and heater capacity. One BTU is the heat needed to raise one pound of water by 1°F. Air conditioners are rated in BTUs - larger homes need higher BTU capacity. For example, a typical 2,000 sq ft home in Texas needs about 30,000-36,000 BTUs of cooling (2.5-3 ton AC unit).

Blower

The fan inside the air handler or furnace that pushes heated or cooled air through ducts into your rooms.

C

Compressor

The "heart" of your air conditioner or heat pump, located in the outdoor unit. It pressurizes refrigerant to enable heat transfer. The compressor pumps refrigerant through the cooling system, making it essential for AC operation. When your compressor fails, your air conditioner won't cool.

Condenser

The outdoor unit of your air conditioning system that houses the compressor, condenser coil, and fan. This is the large metal box outside your home that releases heat from inside to cool your house.

Condenser Coil

Part of the outdoor unit that releases heat absorbed from inside your home (in cooling mode) or collects heat from outside (in heating mode for heat pumps). The coil's metal fins help dissipate heat efficiently.

Cooling Capacity

How much cooling power an air conditioner provides, measured in BTUs or tons. A properly sized AC unit matches your home's cooling needs - too small won't cool effectively, too large causes humidity problems.

CFM

(Cubic Feet per Minute) See Airflow above.

D

Ductwork

The network of metal or flexible tubes that distributes heated or cooled air throughout your home. Leaky ducts can waste energy and reduce comfort.

Ductless Mini-Split

A zoned system without ducts, ideal for additions or homes without existing ductwork.

E

Evaporator Coil

Located inside (usually in the air handler), this coil absorbs heat from indoor air as refrigerant evaporates, cooling your home.

Energy Efficiency Ratio (EER)

Measures cooling efficiency under specific conditions. Higher EER = more efficient AC.

Expansion Valve

Regulates refrigerant flow into the evaporator coil.

F

Freon

A brand name for refrigerant that became the common term for AC coolant. Older systems used R-22 Freon (being phased out), while modern air conditioners use R-410A refrigerant. "My AC needs Freon" usually means your system is low on refrigerant due to a leak.

Furnace

The heating component of an HVAC system that burns fuel (gas) or uses electricity to warm air, then blows it through ducts.

H

Heat Pump

A versatile system that provides both heating and cooling by moving heat rather than generating it. Efficient in moderate climates like parts of Texas.

HSPF

(Heating Seasonal Performance Factor) Measures a heat pump's heating efficiency over a season. Higher HSPF means better performance and lower heating costs.

HVAC

Stands for Heating, Ventilation, and Air Conditioning — the full system that controls your home's temperature, humidity, and air quality.

L

Load Calculation (Manual J)

Professional assessment to size your HVAC system correctly — too big or small wastes money.

M

MERV Rating

Measures air filter efficiency (Minimum Efficiency Reporting Value). Higher MERV (e.g., 8–13) traps more particles like dust, pollen, and allergens for better indoor air quality.

P

Pilot Light

Small flame in older furnaces that ignites the burner (many modern units use electronic ignition).

R

Refrigerant

The cooling fluid (commonly R-410A, also called Puron, or newer low-GWP options) that cycles through your air conditioner or heat pump to absorb, transfer, and release heat. Low refrigerant means your AC won't cool properly and may indicate a leak that needs professional repair.

Refrigerant Leak

When refrigerant escapes from your AC system through cracks or holes in coils or connections. Signs include reduced cooling, ice on the outdoor unit, or hissing sounds. Refrigerant leaks require immediate professional repair.

Return Air

Air pulled back into the system to be re-conditioned.

S

SEER (Seasonal Energy Efficiency Ratio)

The standard rating for air conditioner and heat pump cooling efficiency. SEER measures how efficiently an AC converts electricity into cooling over an entire cooling season. Higher SEER ratings (16+ or 20+) mean lower electric bills. Texas minimum is 14 SEER for new air conditioners. Think of SEER like MPG for cars - higher numbers save more money.

SEER Rating

See SEER above. The numbered rating (14, 16, 18, 20, etc.) that indicates your air conditioner's energy efficiency. When shopping for a new AC, higher SEER ratings cost more upfront but save significantly on cooling costs in hot climates like Forney, Texas.

Split System

The most common residential HVAC setup: an outdoor unit (condenser/compressor) paired with an indoor unit (air handler/evaporator).

T

Thermostat

The control device that sets your desired temperature and signals the HVAC system to heat or cool. Smart thermostats optimize energy use.

Ton (Air Conditioner Size)

A unit of air conditioning cooling capacity. One ton equals 12,000 BTUs per hour of cooling. Common residential AC sizes: 1.5 ton (18,000 BTU), 2 ton (24,000 BTU), 2.5 ton (30,000 BTU), 3 ton (36,000 BTU), and 4 ton (48,000 BTU). Most Texas homes need 2-4 ton air conditioners depending on square footage, insulation, and climate.

Two-Stage Compressor

Operates at low or high capacity for more consistent temperatures and efficiency.

V

Variable Speed Blower

Adjusts fan speed for quieter operation, better humidity control, and energy savings.

Vents/Registers

Openings where conditioned air enters rooms.

Z

Zoning

A system that divides your home into zones with separate thermostats and dampers, allowing customized temperatures in different areas for better comfort and efficiency.

No terms found

Try searching for something else or browse by letter above