References

• BTU
  British Thermal Unit. The amount of heat required to raise the temperature of one pound of water (about one pint) by one degree Fahrenheit.
• 12,000 BTU
  A ton of cooling/heating
• Compressor
  A component of a refrigeration system, known as the workhorse of the system. It pumps the refrigerant under different pressure through the evaporator and condenser sections.
• Condenser
  In a refrigeration system it's the component which rejects the heat. This is where refrigerant changes from a vapor into a liquid state.
• Evaporator
  In a refrigeration system it is the system that absorbs heat. It adds heat to the liquid refrigerant and changes it to a gaseous state.
• Expansion Devise
  A controlling device for regulating the flow and expansion of refrigerant from a high-pressure liquid to a lower pressure, lower temperature mixture of liquid and gas.
• HSPF
  Heating Seasonal Performance Factor. The rating of the heatpump's efficiency during the heating cycle.
• SEER
  Seasonal Energy Efficiency Ration. It is the number of BTU's cooling received for each watt of electricity used.