Efflorescence

A white powder that forms on the surface of brick.

Electrical Breaker

An electrical safety device used to prevent circuit overload. Breakers, if tripped, can be reset.

Electrical Control

A control system that operates on line or low voltage and uses a mechanical means, such as a temperature-sensitive bimetal, to perform control functions, such as actuating a switch or positioning a potentiometer. The controller signal usually operates or positions an electric actuator, or may switch an electrical load either directly or through a relay.

Electrical Heating

Any of several methods that convert electrical energy into usable heat.

Electrical Outlet

A point on the wiring system where current can be taken to activate equipment.

Electrochromics

Glazing with optical properties that can be varied continuously from clear to dark with a low-voltage signal. Ions are reversibly injected or removed from an electrochromic material, causing the optical density to change.

Electromagnetic Spectrum

Radiant energy over a broad range of wavelengths.

Electronic Air Cleaner (EAC)

An electronic device that filters out large particles and contaminants in indoor air. It then electronically pulls out tiny particles that have been magnetized, such as viruses and bacteria, drawing them to a collector plate.

Electronic Control

A control circuit that operates on low voltage and uses solid-state components to amplify input signals and perform control functions, such as operating a relay or providing an output signal to position an actuator. The controller usually furnishes fixed control routines based on the logic of the solid-state components.

Elevation

A geometric projection of a vertical plane perpendicular to the horizon, e.g., of the external upright parts of a building from front, side or rear view.

Ell

An extension of building at right angles to its length.

Embedment/ Embedded

Set firmly into a surround mass.

Emergency Exit Window

Fire escape window (egress window) large enough for a person to climb out. In U.S. building codes, each bedroom must be provided with an exit window. The exact width, area, and height from the floor are specified in the building codes.

Emittance

The ratio of the radiant flux emitted by a specimen to that emitted by a blackbody at the same temperature and under the same conditions.

Emulsification

The entrainment of one substance into another, i.e., oil in water or oil in refrigerant.

Energy Balance

Energy cannot be created or destroyed during heat transfer therefore the amount of energy leaving the source must equal the amount reaching the sink.

Energy Conservation

The deliberate design of a building or process to reduce its energy usage, or to increase its energy efficiency.

Energy Consumption

This represents running costs, which can be broken down to indicate the principal causal factors. Issues such as-- larger windows - heat gains from lights are inter-related and affect energy consumption. For example, the electrical power savings which result from enhanced daylight utilization can significantly outweigh the higher heating energy consumption.

Energy Efficiency

The efficient use of energy with minimum waste.

Energy Efficiency Ratio (EER)

A ratio calculated by dividing the cooling capacity in Btu's per hour (Btuh) by the power input in watts at a given set of rating conditions, expressed in Btuh per watt (Btuh/watt).

Enthalpy

The quantity of internal energy of a body plus the product of its volume and pressure.

Enthalpy Control

An energy management function, which is similar to economizer control, only more sophisticated. In enthalpy control, the total heat content (sensible + latent) of the building return air and outside air is measured, and the enthalpy controller adjusts the dampers to select the air with the least total heat content for cooling.

Environmental Temperature

The temperature of the air outside a room or zone. (see ambient temperature).

EPA

An acronym for the United States Environmental Protection Agency.

Equivalent

Having an equal value, amount or force.

Erosion

The group of natural processes, including weathering, dissolution, abrasion, corrosion, and transportation, by which material is worn away.

Escutcheon

Decorative metal piece that fits over or around a pipe protruding from a wall, or over a faucet body, or around a lockset on the face of a door.

Estimated

Roughly, broadly from experience, not from calculations. Not to be taken as exact.

Evacuated Glazing

Insulating glazing composed of two glass layers, hermetically sealed at the edges, with a vacuum between to eliminate convection and conduction. A spacer system is needed to keep the panes from touching.

Evaporation

The process a liquid goes through to change phase from a liquid to a vapor.

Evaporator

The part of a refrigeration system that gets cold. It is called the evaporator because it is the part of the system that evaporates the refrigerant from liquid to vapor.  Heat exchanger where the system heat is absorbed and the refrigerant evaporates into a gas. By continually pulling refrigerant vapor out of the evaporator headspace, low pressure can be maintained causing the refrigerant to evaporate rapidly. Evaporation cools the refrigerant. This cold refrigerant produces chilled water by heat transfer. The evaporator side is commonly referred to as the closed loop system (chill water).