AEE Business Energy Professional key terms

ASHRAE Standard 90.1 sets minimum energy efficiency requirements for commercial and high-rise residential buildings, covering envelope, lighting, HVAC, service water heating, and power. Most U.S. commercial energy codes adopt or reference it, so compliance calculations and trade-offs follow its rules.

The International Energy Conservation Code is a model code published by the International Code Council; the commercial provisions reference ASHRAE 90.1 as an alternative compliance path. Jurisdictions adopt it with local amendments, setting the legal efficiency floor for new construction and major renovations.

Lighting power density is the installed lighting wattage in a space or building divided by its floor area, usually expressed in watts per square foot or square meter. Codes cap it by building type and space type, and designers trade it against other measures.

Leadership in Energy and Environmental Design is a third-party green building rating system administered by the U.S. Green Building Council. Projects earn points across categories such as energy, water, materials, and indoor environment, and certify at levels from Certified through Platinum.

A building that produces at least as much renewable energy on site, or purchased from off-site renewable sources, as it consumes over a year, measured in site or source energy depending on the stated definition. Boundaries must be stated explicitly.

Load factor is average load divided by peak load over a period, computed from kWh and kW. A high load factor means demand is steady, which typically lowers the effective cost per kilowatt-hour because fixed demand charges are spread over more energy.

Power factor is real power in kilowatts divided by apparent power in kilovolt-amperes. Low power factor from motors and lightly loaded equipment increases current and losses, and many utilities bill a reactive power or power factor charge.

A degree-day measures how far the average daily outdoor temperature falls below (heating) or rises above (cooling) a reference balance point, usually 65 degrees Fahrenheit. Summed over a season, degree-days normalize energy use for weather and support billing analysis.

The affinity laws state that fan or pump flow varies with speed, pressure with speed squared, and power with speed cubed at constant impeller diameter. A 20 percent speed reduction therefore cuts shaft power by roughly half.

A demand ratchet sets a monthly billing demand floor based on a percentage of the highest demand reached in prior months, often 60 to 90 percent over eleven months. Ratchets penalize short peaks long after they occur and can dominate a cost analysis.

A time-of-use rate prices electricity differently by time block, with on-peak periods costing far more than off-peak or super-off-peak periods. Shifting load or storage charging into cheap blocks can reduce bills without cutting total consumption.

A standby or supplemental service charge applies when a customer keeps utility service available but supplies much of its own power, such as with CHP. It covers fixed grid costs and often includes reserved capacity charges, exit fees, and departing-load charges.

In natural gas markets, the basis is the price difference between a pipeline delivery point and a benchmark hub such as Henry Hub. Basis contracts isolate and hedge this location spread while the hub price floats with the market.

A procurement strategy in which the buyer locks in a set volume of electricity or gas at a fixed price for a defined term. It removes price risk on that block but leaves volume risk if consumption falls below the contracted quantity.

An index product prices each unit of energy at a published market index plus a fixed adder, settling monthly. Buyers gain the average market price and avoid locking in at a peak, but accept full commodity price volatility.

Energy use intensity expresses annual energy consumption per unit of floor area, typically kBtu per square foot per year or kWh per square meter. It allows comparison across buildings and against benchmarks, but must be weather-normalized and adjusted for operating hours.

Weather normalization adjusts metered energy use to what would have occurred under average weather, using regression against degree-days or temperature. It removes weather-driven variation so savings, budgets, and benchmark comparisons reflect performance rather than climate.

An energy baseline is the modeled or metered consumption level for a defined period and boundary, adjusted for routine factors such as weather, occupancy, and production. Measurement and verification compares post-installation use against this adjusted baseline to quantify savings.

Scope 2 covers indirect greenhouse gas emissions from purchased electricity, steam, heat, or cooling. It is reported two ways: location-based using grid average factors, and market-based using contractual instruments such as RECs or supplier-specific factors.

An emission factor converts activity data, such as kWh or therms, into greenhouse gas emissions, usually in pounds or kilograms of carbon dioxide equivalent per unit. Factors differ by fuel, region, and year and must match the inventory method.

A renewable energy credit is a tradable certificate representing the environmental attributes of one megawatt-hour of renewable generation. Retiring RECs lets a buyer claim renewable electricity in market-based Scope 2 accounting, even if the electrons are grid-mixed.

Interval data records consumption or demand in short, fixed increments, commonly 15, 30, or 60 minutes. Load shapes from interval data reveal peaks, baseload, scheduling problems, and rate switching opportunities that monthly totals hide.

Submetering installs separate meters downstream of the utility meter to allocate energy to tenants, departments, or major systems. It supports tenant billing, benchmarking, and savings verification, but requires care with metering boundaries and data quality.

Calibration compares an instrument's reading against a traceable reference standard and documents the deviation, adjusting it if needed. Uncalibrated sensors can bias an entire measurement and verification analysis, so calibration status should be checked before fieldwork.

An infrared camera images surface temperature differences to reveal missing insulation, thermal bridging, air leakage paths, moisture, and overheating electrical connections. It is most reliable under a deliberate temperature and pressure difference across the building envelope.

Simple payback divides first cost by annual savings to give the years needed to recover the investment. It is easy to communicate but ignores savings after payback, time value of money, and escalation, so it should not be the only screening test.

Life-cycle cost analysis sums present-value capital, energy, maintenance, and replacement costs over a study period, often using a discount rate and energy escalation. It ranks alternatives on total cost rather than first cost.

In an energy performance contract, an energy service company guarantees a level of savings and uses them to fund project costs, with the guarantee backed by measurement and verification. Payments and remedies are tied to verified results.

A power purchase agreement is a long-term contract to buy electricity at a fixed or escalating price from a specified generator, commonly solar, wind, or on-site CHP. The developer owns the asset, and the host avoids capital cost while securing price certainty.

The International Performance Measurement and Verification Protocol defines standardized M&V options for quantifying savings, covering retrofit isolation, whole-building, and calibrated simulation approaches. It establishes baseline, adjustment, and reporting conventions that make savings claims auditable and comparable.

Retrocommissioning applies the commissioning process to an existing building that was never commissioned or has drifted from its design intent. It targets low-cost operational fixes, controls corrections, and scheduling changes before capital upgrades.

A functional performance test verifies that a system or component meets its documented sequence of operation under controlled conditions, including modes, safeties, and interlocks. Results are recorded and reviewed before acceptance, and failures generate punch-list issues.

An air-side economizer uses cool outdoor air instead of mechanical cooling when outdoor conditions permit, typically through damper modulation and a control changeover. Faulty economizer dampers and sensors are a common and costly source of wasted energy.

A variable frequency drive controls an alternating-current motor's speed by varying the frequency and voltage supplied to it. Applied to fans and pumps, it matches output to load and captures the cubic power reduction described by the affinity laws.

Compressed-air specific power is the electrical input in kilowatts required to produce a given flow, commonly kW per 100 cfm. Comparing it against a baseline exposes leaks, artificial demand, and poor compressor sequencing.

Boiler thermal efficiency is useful steam or hot water output divided by fuel energy input. Stack losses from excess air and flue temperature dominate dry-gas losses, so tuning air-fuel ratio and recovering heat raise efficiency measurably.

Heat rate is the fuel energy input required per unit of useful output, such as Btu per kWh for a generator or Btu per pound of steam for a boiler. Lower heat rate means higher efficiency; it is the inverse of efficiency after unit conversion.

An absorption chiller produces chilled water using heat rather than a mechanical compressor, driving a refrigerant cycle with a lithium bromide or ammonia absorbent pair. It suits sites with cheap waste heat or steam, such as CHP plants.