A/C & Heating 101


Sometimes we in the Air Conditioning and Heating field use terminology that to the layperson sounds like a foreign language, so here we will explain what this jargon means to you, the layperson.

HVAC – Heating, Ventilation, and Air Conditioning. Encompasses the whole system.

SEER – Seasonal Energy Efficiency Rating – Refers to the efficiency of the system. The Higher the number the more efficient & cost effective the system is.

Central Air Conditioning unit – This can be either:
1) A Package unit, usually seen in Manufactured/Mobile Home, with this system the condenser, compressor and evaporator are all in one cabinet placed on the roof or next to the house. This kind of air conditioner often includes electric heating coils or a natural gas furnace. This type of unit eliminates the need for a separate furnace indoors as the A/C and central heater are combined.

2) A Split System, which has a separation between the condenser and evaporator.
The condenser and compressor are in a cabinet outside the house, as the evaporator is in its own cabinet inside. As hot air is removed and transported to an evaporator coil as a warm liquid, the expansion of the liquid caused it to cool, thus cooling the air.

Compressor – An air conditioning compressor is a mechanical motor which pumps and compresses the Freon gas into the high pressure side of the cooling cycle and causes the refrigerant to circulate through the system. It is the most expensive and important component in a system and without it there is no cooling. It is usually found inside the condensing unit.

Condenser – The outside or condensing unit in a residential system is commonly referred to as a condenser because it is the part of your system which condenses the refrigerant or Freon.

Evaporators or Evaporator Coils – Referred to as a cooling coil or indoor coil. Liquid refrigerant or Freon travels through a sealed copper tube and into the evaporator coil and then goes through a very tiny hole or metering device causing the liquid’s pressure to drop significantly. This causes the refrigerant to expand which turns it into a low temperature. Low pressure gas.

Fan Coils – A fan coil is an indoor component of an air conditioning or heat pump system. It is in effect an electric furnace or heater with an evaporator coil, a resistance heater, a blower and a drain pan built inside. The electric heater provides heat on cold days and the evaporator supplies cold on hot days.

Freon or refrigerant – The cooling medium of an air conditioning or refrigeration system is called a refrigerant. In most residential air conditioning and many refrigeration systems is called R-22 or Freon which is a chlorofluorocarbon or CFC. Freon is an EPA controlled substance which is deemed hazardous if released into the environment and will cause damage to the Earth’s ozone layers if not properly contained.

Heat Pumps – Heat pumps are a lot like air conditioners but give out both heating and cooling. Heat pumps and air conditioners both work on the same basic principles but heat pumps have a few extra controls like a reversing valve which effectively reverses the flow taking the heat from outside and transferring it inside for use in the colder winter months.

Humidistat
– All top quality brands have the ability to control the humidity in your home. Sometimes it is a separate control that monitors and controls the humidity.
Carrier calls theirs “Thermidistat”.

Thermostat – Maintains the proper desired temperature in homes and businesses by signaling to your HVAC equipment when appropriate temperature setting are reached. There are several types of thermostats available and they can vary from the simple to the complex.

Two Speed Central Air Conditioning – Two speed units are very much like traditional Air conditioners but they can run on low speed up to 80% of the time, which uses less electricity than a conventional unit. When temperatures rise, two speed units shift into high speed to maintain the set point of the thermostat.

Ultraviolet Filters – Is a frequency of energy generated by the sun. Since UV is invisible it is not really light but the term ultraviolet light has become the standard term for UV energy. Most light sources generate a small amount of UV but in order to purify air UV must be generated by electric lamps similar to ordinary fluorescent lights.

Zoning or Zones HVAC Systems – Zoned cooling is the process or dividing a home or building into two or more separate zones which gives more control over the cooling and heating system allowing for individual control of temperature in each of these zones. There are several ways of accomplishing this depending on the size of the home or building.