The ratio or percentage of useful work or energy output to total work or energy input in any energy system For example, the efficiency of a home heating system is equal to the percentage of energy in the fuel or other source that is converted into useful heat See Efficiency, Efficient, Inefficient
technologies and measures that reduce the amount of electricity and/or fuel required to do the same work, such as powering homes, offices and industries
The amount of input energy required per unit of output energy service provided by an energy-consuming device; also, efforts or activities that aim at reducing the energy used by specific end-use devices and systems, typically without affecting the services provided Examples include high-efficiency appliances, efficient lighting programs, high-efficiency heating, ventilating and air conditioning (HVAC) systems or control modifications, efficient building design, advanced electric motor drives, and heat recovery systems
The act of using less energy/electricity to perform a given function, as distinguished from conservation, which implies accepting less Energy efficiency efforts differ from DSM programs in that the latter are focused on impacting the peak rate of usage, as versus the quantity of energy used to perform a function Many people use these terms interchangeably, which is often incorrect
Quantitatively, the more energy that can be produced per unit mass of fuel, the more efficient is the energy production The efficiency with which energy is utilised can be increased by both improving energy supply technology an managing energy demand more effectively
The amount of fuel needed to sustain a particular level of production or consumption, in an industrial or domestic enterprise Energy efficiency measures are designed to reduce the amount of fuel consumed, either through greater insulation, less waste, or improved mechanical efficiencies, without losing any of the value of the product or process Improving energy efficiency is a technological means to reduce emissions of greenhouse gases without increasing production costs (Source: Mintzer, 1992)
Refers to programs that are aimed at reducing the energy used by specific end-use devices and systems, typically without affecting the services provided Such savings are generally achieved by substituting technically more advanced equipment to produce the same level of end-use services (e g lighting, heating, motor drive) with less electricity
Using less energy/electricity to perform the same function Programs designed to use electricity more efficiently -- doing the same with less For the purpose of this paper, energy efficiency is distinguished from DSM programs in that the latter are utility-sponsored and -financed, while the former is a broader term not limited to any particular sponsor or funding source "Energy conservation" is a term which has also been used but it has the connotation of doing without in order to save energy rather than using less energy to do the same thing and so is not used as much today Many people use these terms interchangeably
In reference to transportation, the inverse of energy intensiveness, i e , the ratio of outputs from a process to the energy inputs; for example, passenger miles traveled (PMT) per gallon of fuel
the amount of useful work or product divided by the fuel or energy input For example, in electrical generation, it is the amount of electricity produced per unit of fuel consumed For air conditioner, it is the amount of cooling provided per unit of electricity used
measure means any capital investment that reduces energy costs in an amount sufficient to recover the total cost of purchasing and installing such measure over an appropriate period of time and maintains or reduces non-renewable energy consumption