AEE Certified Energy Auditor key terms

A preliminary walk-through survey that identifies obvious energy waste, establishes a baseline of utility costs and consumption, and lists low-cost or no-cost measures. It gives approximate savings estimates without detailed measurements or modeling.

An energy survey and analysis that breaks consumption down by end use, uses utility bill analysis plus some spot measurements, and provides a prioritized list of measures with energy and cost savings. It typically includes economic screening of each measure.

A detailed analysis of capital-intensive modifications, often called an investment-grade audit. It relies on calibrated simulation or engineered calculations, detailed cost estimates, and rigorous economic analysis to support financing decisions for major retrofits.

A building's annual energy consumption divided by its floor area, expressed in kBtu per square foot per year or kWh per square meter per year. It allows comparison of buildings with similar function and supports benchmarking against peers or targets.

The process of splitting total metered energy into the systems that consume it, such as lighting, heating, cooling, fans, and plug loads. It shows where savings opportunities are largest and guides the scope of an audit.

The reference period of consumption and cost against which future performance and savings are measured. It is usually adjusted for weather, occupancy, and operational changes so that comparisons remain fair over time.

A measure of how far the daily mean outdoor temperature falls below (heating) or rises above (cooling) a reference temperature, summed over a period. It tracks weather-driven load and supports weather normalization.

The average load over a period divided by the peak load in that same period. A low value signals peaks that drive demand charges and equipment sizing, pointing to load-shifting or peak-shaving opportunities.

The process of using measurements to determine the savings actually achieved by an energy measure, following a documented protocol such as IPMVP. Savings are found by comparing measured post-installation use with an adjusted baseline.

Meter readings recorded at fixed short intervals, typically 15, 30, or 60 minutes, rather than monthly totals. It reveals load shapes, peaks, scheduling problems, and equipment cycling that monthly bills hide.

Statistical adjustment of energy use to remove the effect of year-to-year weather variation, typically using degree days or regression. It lets auditors compare performance across periods and set realistic baselines.

A model that relates energy use to an independent variable such as outdoor temperature, allowing for a change in slope at a balance point. It captures the temperature below or above which heating or cooling begins.

The initial capital cost of a measure divided by its annual energy cost savings, expressed in years. It is quick and easy to communicate but ignores savings after payback and the time value of money.

A method that sums all costs of an option over its study period, including purchase, installation, energy, maintenance, and replacement, with future costs discounted to present value. It compares alternatives on total economic impact.

The present value of a project's future cash flows minus its initial cost, using a chosen discount rate. A positive result means the measure earns more than the required return and adds value.

The rate used to convert future cash flows into present value, reflecting the cost of capital and risk. A higher rate makes future savings worth less and favors measures with quicker returns.

The ratio of light output in lumens to electrical power input in watts for a lamp or luminaire, expressed in lumens per watt. Higher efficacy means more light for the same energy and is central to lighting comparisons.

Installed lighting wattage in a space divided by its floor area, expressed in watts per square foot or square meter. It is compared against code or standard limits and is a key metric in lighting audits.

The fraction of lamp lumens that actually reach the work plane in a given room, accounting for luminaire efficiency and room surface reflectance. It is used in the lumen method to estimate illuminance.

A description of the apparent color of a white light source, stated in kelvin, ranging from warm near 2700 K to cool at 5000 K and above. It guides lamp selection for occupant comfort and appearance.

A control strategy that uses cool outdoor air instead of mechanical cooling when outdoor conditions allow, by modulating dampers and relieving excess air. It reduces compressor energy in mild or cold weather.

The ratio of useful cooling or heating output to the energy input, expressed in consistent units. A higher COP means greater efficiency; seasonal metrics such as SEER and HSPF average performance across operating conditions.

An air distribution system that varies the volume of supply air to each zone while the central fan modulates, rather than varying supply temperature. It matches airflow to load and saves fan energy at part load.

Raising the chilled water supply temperature as load decreases to improve chiller efficiency while still meeting the highest zone demand. It requires controls that monitor valve positions or zone conditions.

A piping loop that keeps hot water circulating so fixtures receive hot water quickly, reducing waiting time and water waste. It saves water but adds pump energy and pipe heat loss.

Energy lost from a water heater and its piping when no hot water is being drawn, driven by tank insulation, jacket losses, and control power. It can be reduced by insulation, timers, or tankless design.

The portion of a building's domestic hot water or space heating load supplied by a solar thermal system. Higher fractions reduce conventional fuel use but require larger collector area and storage.

An electronic device that adjusts the speed of an AC motor by changing the frequency and voltage of its supply. Because fan and pump power varies roughly with the cube of speed, part-load savings are large.

The electrical power required to produce a unit of compressed air flow, typically kW per 100 cfm, at a stated pressure. It benchmarks system efficiency and reveals leaks, pressure problems, or poor controls.

The extra compressed air consumed because system pressure is higher than the end uses require, increasing flow through unregulated openings and leaks. Lowering pressure reduces this waste without hurting production.

A path through the building envelope where heat flows much more readily than through surrounding assemblies, such as steel studs, slab edges, or balcony connections. It lowers effective insulation value and can cause condensation.

The overall rate of heat transfer through an assembly, expressed in Btu per hour per square foot per degree Fahrenheit or in watts per square meter kelvin. It is the reciprocal of R-value, and lower values indicate better insulating performance.

Unintended outdoor air entering a building through cracks, joints, and penetrations, driven by wind and stack pressure. A blower door test quantifies envelope leakage and helps locate major leaks.

A networked control system that monitors and commands HVAC, lighting, and other building equipment through sensors, controllers, and a central interface. It enables scheduling, setpoints, alarms, and trend logging.

The written logic that defines how equipment, valves, and dampers respond to inputs such as temperature, pressure, or schedule. Well-tuned sequences prevent simultaneous heating and cooling and wasted operation.

A group of solar modules that convert sunlight directly into direct-current electricity, later inverted to alternating current for building use or export. Output depends on irradiance, temperature, orientation, and shading.

The share of electrical energy put into a storage system that is returned on discharge, accounting for charging, conversion, and standby losses. It directly affects the cost and emissions benefit of storage.

On-site generation of electricity and useful heat from a single fuel source, with heat recovered for space heating, hot water, or process use. High overall efficiency depends on matching heat and power loads.

Practices and technologies that cut engine idling in vehicles, such as automatic shutoff, shore power, or auxiliary heaters. Idling burns fuel with zero miles traveled and accelerates engine wear.

Total greenhouse gas emissions associated with a fuel or vehicle, from extraction and production through combustion at the wheels. It allows fair comparison of conventional, electric, and alternative-fuel transport options.