Understanding HVAC Terms

What does that mean? Air Repair Heating & A/C knows that a typical household isn’t usually educated with the ins and outs of their Heating & Cooling System, only the use of the controls and temperature adjustment. Hopefully this will help you understand a little more about the information we share on our website. The more you understand, the better decisions you can make for your home.

Glossary of Terms

AIR CONDITIONER: A mechanical device used to control temperature, humidity, cleanliness, and movement of air in a confined space.

Btu/h (British Thermal Units per Hour): A term that is used to measure cooling or heating capacity.

CAPACITY or LOAD: A refrigeration rating system usually measured in Btu/h.

COMPRESSOR: A pump found in a refrigeration or air-conditioning system, which pumps refrigerant through pipes between an outdoor and an indoor unit using pressure.

HEAT PUMP: An air-conditioning system that is capable of reversing the direction of refrigerant flow to provide either cooling or heating to the indoor space.

HSPF (Heating Season Performance Factor): A rating of the seasonal efficiency of a heat pump unit when operating in the heating mode.

HVAC: A term which stands for Heating, Ventilation, and Air Conditioning.

INDOOR UNIT: The air-handler of an air-conditioning system, which contains a heat exchange coil, filters, and fan and provides conditioned air into the space.

INVERTER TECHNOLOGY: Mitsubishi Electric’s MSY, MSZ and MXZ and all P-Series outdoor units use INVERTER-driven compressor technology(Variable Frequency Drive)to provide exceptional indoor, high-speed cooling and heating. By responding to indoor and outdoor temperature changes, these systems reduce power consumption by varying the compressor speed for extra energy savings.

MICROPROCESSOR: An electrical component consisting of integrated circuits, which may accept, store, control, and output information.

OUTDOOR UNIT: A component of an air-conditioning system which contains compressor, propeller fan, circuit board, and heat exchange coil. It pumps refrigerant to/from indoor unit.

REFRIGERANT: A gas/liquid substance used to provide cooling by direct absorption of heat.

REFRIGERANT LINES: Copper tubing through which refrigerant flows to and from indoor and outdoor units.

SEER (Seasonal Energy Efficiency Ratio): A rating of the seasonal efficiency of air-conditioning or heating units in cooling mode.

SPLIT-DUCTLESS SYSTEM: A system comprised of a remote outdoor condensing unit connected by refrigerant pipes to a matching, non-ducted indoor air-handler, and a remote controller. Special cases for introducing fresh air may call for limited ducting to air-handler from outside.