CEA key terms

The documented boundary defining which facilities, systems, fuels, and time periods an audit covers, including what is excluded and why, so findings and savings estimates are interpreted correctly.

A tiered classification of audit depth: Level 1 is a walk-through screening with rough savings, Level 2 adds detailed system analysis and costed measures, Level 3 adds rigorous engineering and financial modeling for capital decisions.

The reference period of historical consumption and cost against which future performance and savings are measured, ideally chosen as a typical year with reliable, complete utility data.

Annual energy consumption divided by a size or activity metric, such as kWh per square metre or gigajoules per tonne of product, allowing comparison of buildings or plants of different sizes.

The pattern of energy demand over time, typically shown as hourly, daily, or seasonal demand curves, revealing peaks, part-load behavior, and scheduling opportunities that drive equipment selection and control strategies.

Average load divided by peak load over a period, expressed as a fraction or percentage; a low value indicates demand peaks that may justify load shifting, storage, or right-sizing rather than energy reduction alone.

The minimum continuous energy demand that persists during unoccupied or non-production hours, often caused by standby equipment, controls left on, or leaks, and a frequent target for low-cost savings.

A reconciliation of energy inputs against end uses and losses within a defined boundary, used to identify unaccounted consumption and prioritize systems for measurement and improvement.

Installing meters below the main utility service to measure consumption of individual systems, tenants, or processes, enabling allocation of costs and verification of savings from specific measures.

A documented process using metered data and agreed methods to determine actual savings achieved by an energy conservation measure, accounting for changes in weather, occupancy, and production.

Statistical adjustment of energy consumption to remove the effect of outdoor temperature variation, typically using heating and cooling degree days, so that different periods can be compared fairly.

A measure of heating or cooling demand obtained by summing the daily differences between a reference base temperature and the mean outdoor temperature, used to model weather-dependent energy use.

The initial capital cost of a measure divided by its annual net savings, giving the number of years to recover the investment; easy to communicate but ignores savings after payback and time value of money.

A method comparing options by summing all costs over the study period, including capital, energy, maintenance, and replacement, discounted to present value, rather than judging on first cost alone.

The sum of future cash flows discounted to today's value using a chosen discount rate; a positive NPV indicates the measure returns more than the required rate of return.

The discount rate at which a measure's net present value equals zero, expressing project profitability as a percentage that can be compared with a company's hurdle rate.

The rate used to convert future costs and savings into present value, reflecting the organization's cost of capital or required return and the risk of the investment.

The ratio of light output to electrical power input, expressed in lumens per watt, used to compare lamp and luminaire technologies and to estimate lighting energy savings.

Installed lighting wattage divided by floor area, typically in watts per square metre, used to benchmark a space against code limits and to size lighting retrofit savings.

Automatic dimming or switching of electric lighting in response to available daylight measured by photosensors, reducing lighting energy while maintaining target illuminance in the space.

A device that detects presence, using passive infrared, ultrasonic, or both, to switch or dim lighting and sometimes HVAC in unoccupied spaces, capturing savings from reduced run hours.

The ratio of useful heating or cooling output to energy input at a given operating condition; higher values mean greater efficiency, and the value varies with source and load temperatures.

An efficiency rating for chillers that weights performance at several partial loads, better representing real operation than a single full-load rating because chillers rarely run fully loaded.

A control strategy or damper arrangement that uses cool outdoor air instead of mechanical cooling when conditions permit, reducing compressor energy during mild weather and shoulder seasons.

Scheduled relaxation of space temperature or ventilation during unoccupied hours so equipment runs less, with savings dependent on building mass, recovery time, and acceptable restart conditions.

The volume of outdoor air supplied to a space per unit time or per occupant, set for indoor air quality; reducing excess ventilation saves conditioning energy but must respect minimum requirements.

The energy required to raise water from supply to delivery temperature plus distribution and storage losses, driven by draw volume, setpoint, and pipe insulation condition.

A pumped piping circuit that keeps hot water available at fixtures; necessary for convenience but a source of standing losses, so pump control and pipe insulation strongly affect DHW energy use.

Thermal wrapping on storage tanks and adjacent piping that reduces standby heat loss, an inexpensive retrofit with predictable savings where tank surfaces are warm to the touch.

An electronic controller that adjusts motor speed to match load instead of throttling or cycling, yielding large savings for fans and pumps because power varies roughly with the cube of speed.

Relationships for centrifugal fans and pumps stating that flow varies with speed, pressure with speed squared, and power with speed cubed, explaining why modest speed reductions save substantial energy.

The ratio of actual output power to nameplate rated power; oversized motors running lightly loaded operate inefficiently, so measuring load guides right-sizing and replacement decisions.

The electrical power required to produce a unit of compressed air flow, such as kW per cubic metre per minute, used to benchmark compressors and detect degradation or poor control.

A systematic inspection, often with ultrasonic detection, that locates leaks in piping, fittings, and tools; leaks typically waste a large share of compressor output and repairs are usually low cost.

The temperature at which moisture condenses from compressed air at system pressure; specifying it correctly for dryers prevents pipe corrosion and product contamination without over-drying and wasting energy.

A path of high-conductivity material through insulation, such as steel studs or slab edges, that bypasses the intended thermal resistance and increases heat flow through the envelope.

Unintentional movement of air through gaps, joints, and penetrations in the envelope, carrying both sensible and latent heat and often a major cause of excess heating and cooling load.

A measure of thermal resistance of a material or assembly, where higher values mean better insulation; assemblies must be rated for their weakest path and installed condition.

A networked control system that monitors and commands HVAC, lighting, and other building equipment through sensors, controllers, and a central interface, generating trend data useful for audits.

A time-stamped record of a sensor or setpoint value collected by a control system, used to diagnose scheduling faults, simultaneous heating and cooling, and equipment short cycling.

The documented logic specifying how equipment responds to conditions, including setpoints, staging, and reset schedules; mismatches between intended and actual sequences commonly waste energy.

On-site generation of electricity and useful heat from one fuel source, achieving higher overall efficiency than separate generation when thermal output can be used year-round.

An electrochemical system that stores electricity for later use, enabling peak shaving, demand charge reduction, and backup, with economics driven by tariff structure and cycle life.

A utility billing component based on the highest average power drawn during a billing period, giving strong incentive to shave peaks through scheduling, storage, or load shifting.

Strategies to reduce transport energy across vehicles, including route optimization, driver behavior, idling reduction, and right-sizing, often supported by telematics data collection.

On-vehicle sensors and communications that record fuel use, idling, speed, and location, providing the data needed to quantify transport energy savings and verify driver or routing changes.

Planning deliveries or service trips to minimize distance, time, and stops, reducing fuel consumption without changing vehicles; savings depend on current routing practice and load constraints.