Lit Floorspace in Lit Buildings

The most useful profile of lighting equipment usage is obtained when analyzing the percent of lit floorspace that is lit by a particular type of lighting equipment. Table 2 provides for different lighting equipment the total floorspace of lit buildings and the total lit floorspace of buildings.

Table 2: Total Floorspace in Lit Buildings and the Total Lit Floorspace in Lit Buildings for Selected Lighting Equipment Types

Lighting Equipment Types	Total Floorspace in Lit Buildings (Million Square Feet)	Total Lit Floorspace in Buildings (Million Square Feet)
Incandescent	35,715	31,750
Standard Fluorescent	53,984	48,438
Compact Fluorescent	14,273	13,329
High-Intensity Discharge	16,259	15,324
Halogen	9,665	9,055
Some Other Type	554	482

Source: Energy Information Administration, 1995 Commercial Buildings Energy Consumption Survey.

Within a particular building, different types of lighting equipment often illuminate overlapping areas of floorspace. For example, a 10,000-square-foot office building has 95 percent of its floorspace lit (5 percent of the floorspace is unused and not lit). There are two lighting equipment types in this office building--incandescent and fluorescent. The incandescent lights are only used at the desk for task lighting, while ceiling fluorescent lights provide the majority of the lighting. Only 10 percent of the lit floorspace is lit by the incandescent desk light, but 100 percent of the lit floorspace is lit by the fluorescent ceiling lights. In 1995, there was 50 billion square feet of lit floorspace in commercial buildings. Table 3 provides both the amount and the precent of that square feet lit by various lighting equipment types (See Figure 2).

10,000-Square-Foot Office Building with Two Lighting Types

Fluorescent

Incandescent & Fluorescent

Unused Space

­ Lit Floorspace

­ Unlit Floorspace

Table 3: Lit Floorspace Lit by Lighting Equipment Types

File Last Modified: January 22, 1998

Contact for Residential Lighting:

robert.latta@eia.doe.gov

Robert Latta

Team Leader, Consumption Analysis & Survey Design

Phone: (202) 586-1385

Fax: (202) 586-0018

Contact for Commercial Lighting:

Joelle Michaels

joelle.michaels@eia.doe.gov

CBECS Manager

Phone: (202) 586-8952

FAX: (202) 586-0018