WHAT IS HVAC?
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Outdoor Coil/Condensing Unit: The portion of a heat pump or central air conditioning system that is located outside the home and functions as a heat transfer point for collecting heat from or dispelling heat to the outside air.
Single Package: A year 'round heating and air conditioning system that has all the components completely encased in one unit outside the home.
Split System: A heat pump or central air conditioning system with components located both inside and outside of a building -- the most common types installed in homes.
Supplementary Heat: The auxiliary or emergency heat provided at temperatures below a heat pump's balance point. It is usually electrical resistance heat.Also known as the heater package. But supplemental heat can also be gas or oil - fired equipment.
Zone: A zone is the area that one thermostat is controlling. For example: A two story house with a thermostat on each floor has two zones, one for each floor.
Technical Heating And Air Conditioning Definitions:
Ton: Heat pumps and air conditioners are generally sized in tons. Typical sizes for single family residences are between two and five tons. Each ton equals 12,000 Btuh.
It is important to note that actual capacity is not constant and will change based on outdoor or indoor temperatures. The published capacity rating of air conditioners and heat pumps is based on performance at the ARI standard temperature levels of 95 F outside, 80 F inside.
Balance Point: An outdoor temperature - usually between 30°F to 45°F - at which a heat pump's output exactly equals the heating needs of the house. Below the balance point, supplementary electric resistance heat is needed to maintain indoor comfort.
Defrost Mode: During the heating cycle of a heat pump, frost may build up on the outdoor coil. To remove the frost and maintain efficiency, the system will automatically defrost itself. This usually only takes a few minutes, then the system automatically switches back to heating. It is normal to see steam rising from the outdoor unit when this happens.
British Thermal Unit (BTU): The amount of heat required to raise the temperature of one pound of water (about one pint) by one degree Fahrenheit.
Coefficient of Performance (COP):A ratio calculated by dividing the total heating capacity provided by the heat pump, including circulating fan heat but excluding supplementary resistance heat (Btu's per hour), by the total electrical input (watts) x 3.412. (See Heating Seasonal Performance Factor, above.)
Energy Efficiency Ratio (EER): A ratio calculated by dividing the cooling capacity in Btu's per hour (Btuh) by the power input in watts at a given set of rating conditions, expressed in Btuh per watt (Btuh/watt). (See Seasonal Energy Efficiency Ratio, above.)
Watt (W): A Watt is a unit of electricity.
Kilowatt (kW) A kilowatt equals 1,000 Watts. A kilowatt hour (kWh) is the amount of kilowatts of electricity used in one hour of operation of any equipment.
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