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"The
Savings Experts" A Simple Glossary of Heating/AC Terms
Air Source Heat Pump - a heating/cooling unit that transfers heat in either direction between the air outside a home and the indoors. Go to Top Of Page Air supply for combustion - the air a furnace, boiler or space heater required to burn fuel. Go to Top Of Page Annual fuel utilization efficiency (AFUE) - a measurement of efficiency that applies to heating appliances. The AFUE of furnaces or boilers measures their performance over a typical heating season. It takes into account things like on-and-off cycles and heat loss through the chimney or vent, and is the most useful furnace and boiler rating available. The higher the rating the more efficient the unit. Go to Top Of Page Aquastat - a thermostat that controls the water temperature in a boiler. Go to Top Of Page Boiler - the heating unit used with a hot water (hydronic) distribution system. Go to Top Of Page British thermal units per hour (Btu/h) - a unit of heat used to measure the heating capacity of heating equipment. Go to Top Of Page Central air conditioner - a unit that cools an entire house by removing heat from the inside air and releasing it outside. Go to Top Of Page Coefficient of performance (COP) - a measurement of heat pump efficiency and is arrived at by dividing the heat output by the energy input. Since the COP of an electric resistance heater is 1.0 - which means that the same amount of energy that goes into it as electricity comes out as heat - any rating higher than 1.0 means that for the same amount of electricity going in, more heat comes out. Go to Top Of Page Controls - devices such as a thermostat that regulate a heating or cooling system. Go to Top Of Page Conventional gas furnace or boiler - a gas heating unit with an annual fuel utilization efficiency (AFUE) less than 70 percent. It exhausts through a masonry chimney or metal "B" vent. Go to Top Of Page Distribution system - the component of a heating or cooling system that delivers warmed or cool air (ductwork) or warmed water (radiators) to the living space. Go to Top Of Page Domestic hot water - hot water used for household purposes. Go to Top Of Page Earth energy system (ground source heat pump) - a heat pump that removes heat from the earth or ground water in cold weather and transfers it to the house through an underground piping system. The process reverses in warm weather and heat is transferred to the ground. Go to Top Of Page Electrical resistance heating - heat produced by passing electricity through a resistor. Go to Top Of Page Energy efficiency ratio (ERR) - a ratio that describes the energy efficiency of earth energy systems and is arrived at by dividing the cooling output of the ground heat pump (in Btu/hour) by the power input (in watts). Look for an ERR of at least 10.5. Go to Top Of Page Energy factor (EF) - used to rate the energy efficiency of storage-type hot water heaters. Both on-cycle efficiency and off-cycle losses are taken into account, which makes it a seasonal rating. The higher the EF the more efficient the unit. You can expect the following EF ratings for new storage-type water heaters: Go to Top Of Page
Flame retention head burner - a higher efficiency burner in an oil furnace. It produces a hotter flame and operates with a lower air flow, thus reducing loss up the chimney. Goto Top Of Page Forced air - a distribution system in which a fan circulates air from the heating or cooling unit to the rooms through a network of ducts. Go to Top Of Page Fossil fuel - a naturally occurring carbon or hydrocarbon fuel such as natural gas, propane and oil, formed by the decomposition of prehistoric organisms. Go to Top Of Page Ground source heat pump - another term an earth energy system. Go to Top Of Page Heat exchanger - a structure that transfers heat from the hot combustion gases in a furnace to the circulating household air or, in a boiler, to the circulating hot water. Go to Top Of Page Heat recovery ventilator (HRV) - a device used in central ventilation systems to reduce the amount of heat that is lost as household air is replaced with outside air. As fresh air enters the house, it passes through a heat exchanger heated by the war, outgoing air stream and is preheated. Go to Top Of Page Heating seasonal performance factor (HSPF) - an efficiency rating for an air source heat pump. It is arrived at by dividing the total heat provided during the season (in Btu) by the total energy consumed by the system (in watt-hours). The higher the rating, the more efficiently the heat pump operates of the entire heating season. Look for a HSPF of over 5.9. Go to Top Of Page High-efficiency (condensing) furnace or boiler - a heating unit with an annual fuel utilization (AFUE) of 90 per cent or more. It has a second stainless steel heat exchanger that removes additional heat from exhaust gases. Water vapor condenses as the exhaust cools. The unit vents through a narrow plastic wall pipe instead of a chimney. Go to Top Of Page Hot water distribution -see hydronic system. Goto Top Of Page Hydronic system - a distribution system in which hot water is circulated through a network of pipes to radiators, wall panels or and under-floor heating system. Go to Top Of Page Installed cost - the total of the purchase price and the installation costs of equipment. Go to Top Of Page Kilowatt - a unit of electrical power used to measure the heating capacity of electric equipment. One kilowatt (kW) equals 1,000 watts (W). Go to Top Of Page Mid-efficiency natural gas or propane furnace or boiler - a gas heating unit with an annual fuel utilization efficiency (AFUE) of 78 to 82 per cent. Most models exhaust through the basement wall. Go to Top Of Page New oil furnace - has flue gases that may be exhausted through a chimney or a side wall vent. Efficiencies (AFUE) range from 78 to 86 per cent. Go to Top Of Page Retrofit - replacement of one or more components of an existing system Go to Top Of Page Seasonal efficiency - a performance rating that considers the heat (or 'cool') actually delivered to the living space, the total energy available in the fuel consumed, and the impact the equipment itself has on the total heating or cooling load through an entire heating season. HSPF, AFUE, SEER and EF are seasonal efficiency ratings. Go to Top Of Page Seasonal energy efficiency ratio (SEER) - a rating of the cooling energy efficiency of air conditioners and air source heat pumps. A SEER rating is arrived at by dividing the total cooling provided during the season (in Btu) by the total energy consumed by the system (in watt-hours). In general, SEERs for new air conditioners and air source heat pumps currently range from 9 to 15. Most areas have minimum efficiency standards that require SEERs of 9 or 10. Go to Top Of Page Setback thermostat - a programmable thermostat with a built-in timer. You can adjust it to vary household temperature automatically. Go to Top Of Page Space heater - a heating unit that supplies heat directly to the room where it is located and is not connected to a distribution system. Go to Top Of Page Steady state efficiency - a measure of a furnace or boiler's efficiency after it has been running a short while and all components have reached their normal operating temperature. The steady-state efficiency of furnaces and boilers is arrived at by comparing the amount of heat that's available in the fuel to the amount they can convert into usable heat. Go to Top Of Page Storage-type water heater - a tank that heats and stores hot water. Go to Top Of Page Ton - a measure of the cooling capacity for central air conditioners and heat pumps. (1 ton = 12,000 Btu/h). Go to Top Of Page Watt - see kilowatt. This site was designed by Phoenix
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