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AC stands for alternating current, and DC stands for direct current.

Available Space

The total amount of space that is currently being marketed as available for lease in a given time period. It includes any space that is available, regardless of whether the space is vacant, occupied, available for sublease, or available at a future date.


A term describing a particular property, developed specifically for a certain tenant to occupy, with structural features, systems, or improvement work designed specifically for the needs of that tenant. A build-to-suit can be leased or owned by the tenant. In a leased build-to-suit, a tenant will usually have a long term lease on the space.

Carbon footprint

A company’s carbon footprint is the amount of CO2 emissions its operations produce. In setting goals to reduce their carbon footprint, many companies target their data centers because they consume 25% or more of the electric bill.


Computational fluid dynamics. CFD is being applied to air flow in data centers for optimal air-conditioning design.

Colocation (Retail Data Center)

Colocation is a general real estate term referring to the renting of adjacent space to multiple tenants, with shared common areas and entrances, for the purpose of running a business that may or may not serve third parties. For the purposes of this report, Colocation refers to turnkey data centers that offer retail services down to the rack or partial rack / cabinet.

Close-coupled cooling

Close-coupled cooling systems located in a rack cool the hot air generated by the servers in just that rack instead of cooling the entire datacenter.


Computer-room air-conditioning system units monitor a data center’s temperature, humidity and air flow. They consume around 10% of a data center’s power.


A machine that uses chilled water to cool and dehumidify air in a data center.

Critical Power Load (Critical Load)

The usable electrical capacity at the data center floor and server cord. It does not include any ancillary load for cooling, lighting, common areas or other equipment.

Critical Cooling Load

The usable cooling capacity at the data center floor. It does not include any ancillary load for lighting, common areas or other equipment.

Carrier Neutral Colocation

Multi-tenant, turnkey data centers that are unaffiliated with a network service provider.

Cap Rate

Short for capitalization rate. The Cap Rate is a calculation that reflects the relationship between one year’s net operating income and the current market value of a particular property. The Cap Rate is calculated by dividing the annual net operating income by the sales price (or asking sales price).

Central Business District

The designations of Central Business District (CBD) and Suburban refer to a particular geographic area within a metropolitan statistical area (MSA) describing the level of real estate development found there. The CBD is characterized by a high density, well organized core within the largest city of a given MSA.

Data Center

A facility used to house computer systems and associated components, such as telecommunications and storage systems. It generally includes redundant or backup power supplies, redundant data communications connections, environmental controls (e.g., air conditioning, fire suppression) and security devices. Also includes colocation, a subset of data centers.


Data center real estate.

Data Center Shell

A building that has been pre-qualified for power and telecom access, with or without any other improvements (i.e. four concrete walls), and amenable to data center development and use. May become a single-tenant property or colocation.


Data Center Infrastructure Efficiency metric shows the power used by a data center’s IT equipment as a percentage of the total power going into the data center. The larger the DCiE, the better.


The company, entity or individual that transforms raw land to improved property by use of labor, capital and entrepreneurial efforts

Direct Space

Space that is being offered for lease directly from the landlord or owner of a building, as opposed to space being offered in a building by another tenant (or broker of a tenant) trying to sublet a space that has already been leased.

Exchange Colocation

Multi-tenant, turnkey data centers where the ISPs interconnect which offer services down to the rack or partial rack / cabinet.

Existing Inventory

The square footage of buildings that have received a certificate of occupancy and are able to be occupied by tenants. It does not include space in buildings that are either planned, under construction or under renovation.

Flex Building

A type of building designed to be versatile, which may be used in combination with office (corporate headquarters), research and development, quasi-retail sales, and including but not limited to industrial, warehouse, and distribution uses. A typical flex building will be one or two stories with at least half of the rentable area being used as office space, have ceiling heights of 16 feet or less, and have some type of drive-in door, even though the door may be glassed in or sealed off.

Full Service Rental Rate

Rental rates that include all operating expenses such as utilities, electricity, janitorial services, taxes and insurance.

Gross Absorption

The total change in occupied space over a given period of time, counting space that is occupied but not space that is vacated by tenants. Gross absorption differs from leasing activity, which is the sum of all space leased over a certain period of time. Unless otherwise noted Gross Absorption includes direct and sublease space.

Growth in Inventory

The change in size of the existing square footage in a given area over a given period of time, generally due to the construction of new buildings.


The service of running servers on behalf of another party, allowing those organizations to focus on managing their applications, instead of hardware and operating system administration. There are various levels of service and various kinds of hosting offered (e.g. dedicated, shared, virtual, etc.).

Industrial Building

A type of building adapted for such uses as the assemblage, processing, and/or manufacturing of products from raw materials or fabricated parts. Additional uses include warehousing, distribution, and maintenance facilities. The primary purpose of the space is for storing, producing, assembling, or distributing product.


Electric power is sold in units called kilowatt hours, 1 kWh is the amount of energy delivered in one hour at a power level of 1000 watts. This abbreviation for “kilowatt hour” (kWh) is mostly used in writing rather than conversation.

Landlord Rep

(Landlord Representative) In a typical lease transaction between an owner/landlord and tenant, the broker that represents the interests of the owner/landlord is referred to as the Landlord Rep.

Leased Space

All the space that has a financial lease obligation, including: all leased space, regardless of whether the space is currently occupied by a tenant. Leased space also includes space being offered for sublease.

Leasing Activity

The volume of square footage that is committed to, and signed under, a lease obligation for a specific building or market in a given period of time. It includes direct leases, subleases and renewals of existing leases. It also includes any pre-leasing activity in planned, under construction, or under renovation buildings.


Geographic boundaries that serve to delineate primary competitive areas. (See also: Region).


Buildings that house more than one tenant at a given time. Usually, multi-tenant buildings were designed and built to accommodate many different floor plans and designs for different tenant needs. (See also: Tenancy).

Net Absorption

The net change in occupied space over a given period of time. Unless otherwise noted Net Absorption includes direct and sublease space.

Net Rental Rate

A rental rate that excludes certain expenses that a tenant could incur in occupying office space. Such expenses are expected to be paid directly by the tenant and may include janitorial costs, electricity, utilities, taxes, insurance and other related costs.

New Space

Sometimes called first generation space, refers to space that has never been occupied and/or leased by a tenant.

Occupied Space

Space that is physically occupied by a tenant. It does not include leased space that is not currently occupied by a tenant.

Parasitic Load

The power and cooling load for all ancillary equipment and common area operation.


Power distribution unit, a device that distributes electric power. PDUs function as power strips for a data center and consume around 5% of the power in a typical center.


Power usage effectiveness is a reciprocal metric embraced by the Data Center Infrastructure Efficiency. PUE is the ratio of the total power going into a data center to the power used by the center’s IT equipment.

Preleased Space

The amount of space in a building that has been leased prior to its construction completion date, or certificate of occupancy date.

Premium Colocation

Tier III+ data centers that generally qualify as extremely desirable and command the highest rents or sale prices compared to other buildings in the same market. They are generally the most attractive and eagerly sought by firms willing to pay a premium for quality.


Calculated by dividing the price of a building (either sales price or asking sales price) by the Rentable Building Area (RBA).

Quoted Rental Rate

The asking rate per square foot for a particular building or unit of space by a broker or property owner. Quoted rental rates may differ from the actual rates paid by tenants following the negotiation of all terms and conditions in a specific lease.


Renewable energy certificates or renewable energy credits are tradable commodities which indicate that 1 megawatt-hour of electricity was purchased from a renewable source, such as solar, wind, biomass or geothermal.


Core areas containing a large population nucleus, that together with adjacent communities have a high degree of economic and social integration. Regions are further divided into market areas, called Markets. (See also: Markets)

Rentable Building Area

(RBA) The total square footage of a building that can be occupied by, or assigned to a tenant for the purpose of determining a tenant’s rental obligation. Generally RBA includes a percentage of common areas including all hallways, main lobbies, bathrooms, and telephone closets.

Rental Rates

The annual costs of occupancy for a particular space quoted on a per square foot basis.


Buildings that are occupied, or intended to be occupied by a single tenant. (See also: Build-to-suit and Tenancy)

Telco-Grade Colocation

Typically Tier II qualify as a more speculative investment, and as such, command lower rents or sale prices compared to Class A properties. Such buildings offer utilitarian space without special attractions, and have ordinary design, if new or fairly new; good to excellent design if an older non-landmark building. These buildings typically have average to good maintenance, management and tenants. They are less appealing to tenants than Class A properties, and may be deficient in a number of respects including floor plans, condition and facilities. They lack prestige and must depend chiefly on a lower price to attract tenants and investors.

Tenant Rep

Tenant Rep stands for Tenant Representative. In a typical lease transaction between an owner/landlord and tenant, the broker that represents the interests of the tenant is referred to as a Tenant Rep.

Time On Market

A measure of how long a currently available space has been marketed for lease, regardless of whether it is vacant or occupied.


Uninterruptible power supply, which provides instantaneous battery backup if a data center’s power fails..

Vacancy Rate

A measurement expressed as a percentage of the total amount of physically vacant space divided by the total amount of existing inventory. Under construction space generally is not included in vacancy calculations.

Vacant Space

Space that is not currently occupied by a tenant, regardless of any lease obligation that may be on the space. Vacant space could be space that is either available or not available. For example, sublease space that is currentlybeing paid for by a tenant but not occupied by that tenant, would be considered vacant space. Likewise, space that has been leased but not yet occupied because of finish work being done, would also be considered vacant space.

Wholesale Turnkey

A datacenter that is designed, supplied, built, or installed fully complete and ready to operate. The term implies that the end user just has to turn a key and start using the product or service.

Year Built

The year in which a building completed construction and was issued a certificate of occupancy.

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