Glossary and FAQs
When purchasing furnaces, air conditioners or heat pumps, consumers will find allot of abbreviations, acronyms and efficiency ratings used to describe the products. Listed below are some common terms used in our industry and a "plain talk" explanation of each.
- Heating, Ventilating and Air Conditioning
- Air Conditioning and Refrigeration Institute is a nonprofit, voluntary organization comprised of manufacturers of air conditioning, refrigeration and heating products. It publishes standards for testing and rating heat pumps and air conditioners in order to provide the consumer with a standardized unit of comparison between equipment of various manufacturers.
- Gas Appliance Manufacturers Association
- Department of Energy is the federal agency in charge of monitoring the consumption of energy sources.
- Watt (W)
- A Watt is unit of electricity.
- Kilowatt (kW)
- A kilowatt is 1000 watts.
- Kilowatt hour (kWh)
- A kilowatt hour is the amount of kilowatts of electricity used in one hour of operation.
- A therm is a unit of measure for natural gas. You will find this term used on your gas bill.
- A British Thermal Unit is the amount of heat required to raise the temperature of one pound of water (about one pint) by one degree Fahrenheit.
- Btu’s per hour.
- A ton is a unit of measure for the cooling capacity of an air conditioner or a heat pump. To determine the number of tons of cooling you must take the Btu’s per hour and divide by 12,000 (Btuh/12,000). Typical sizes for single family residences are between 2 and 5 tons. For example, a 3 ton air conditioner will remove 36,000 Btuh ( 3 X 12,000). The actual capacity of a unit will change based on indoor and outdoor conditions. The published rating of a unit is based on its performance at the ARI standard temperature levels: 95°F outside, 80°F inside.
- Seasonal Energy Efficiency Ratio applies to air conditioners and heat pumps and describes the relationship between the Btuh, or cooling capacity of a unit, and the amount of electricity required to run the unit. This ratio is based on normal annual usage. Units with higher SEER ratings require less electricity to cool a home and are therefore more efficient.
- Annual Fuel Utilization Efficiency. This rating applies to gas furnaces and is based on average usage and includes fuel usage during on and off cycling. The higher the AFUE rating, the less fuel a furnace or boiler will use.
- The Coefficient of Performance is a ratio used in rating the heating efficiency of heat pumps. It is determined by dividing the total heating capacity (excluding supplementary resistance heat) by the total electric input.
- A decibel describes the relative loudness of a sound.
- A bel is a decibel divided by 10.
- Sound Rating is measured in bels. The SR of a unit (heat pump or air conditioner) is based on tests performed at ARI standard rating conditions. Although no energy consumption is tied to the SR, it can directly affect the consumer’s comfort (as well as that of a neighbor!). Average sound ratings range from 7.2 to 8.2. Lower numbers indicate quieter units.
- The compressor is the major component located in your outdoor unit (heat pump or air conditioner). New units are sold with a 5 year or 10 year limited warranty form the manufacturer on this part. When the compressor fails after the warranty has expired it usually means the replacement of the entire unit due to the high cost of the compressor alone.
- The condenser is a term referring to the outdoor unit (air conditioner). It is called the condenser because it is where the refrigerant goes from a gas to a liquid (condenses) in the refrigeration cycle.
- The evaporator is the indoor coil used in air conditioning. It is called the evaporator because it is where the refrigerant goes from a liquid to a gas (evaporates) in the refrigeration cycle.
- Heat Exchangers
- This term refers to the components in a gas furnace in which the actual combustion takes place. Typically the manufacturers place a 20 year limited warranty on the heat exchangers. On the highest efficiency furnaces the heat exchangers are warranted for as long as you own your home.
- Inducer Fan
- The inducer fan helps send the products of combustion up the chimney or through the appropriate exhaust vent. This component is only found on the newer generation of furnaces with efficiencies of 78% AFUE and higher.
- Hot Surface Ignition
- This component replaces the traditional pilot on a gas furnace. A hot surface ignition will "turn on" when the furnace is starting and "turns off" once the burners are lit. Because this is only in use when the furnace is starting there is no wasted energy from continuous pilot operation