Commercial buildings have begun using more efficient lighting types according to EIA survey
The most recent Commercial Buildings Energy Consumption Survey (CBECS) collected new information about lighting control technologies and strategies in the United States in 2012, according to the US Energy Information Administration.
Compared with other investments in energy efficiency—such as upgrading heating, ventilation, and air-conditioning systems or replacing insulation—lighting controls are often relatively easy, accessible, and affordable changes.
A new EIA report, Trends in Lighting in Commercial Buildings, details these strategies and provides information about lighting technologies in commercial buildings.
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Lighting control technologies provide the appropriate level and type of lighting to a building and save on electricity costs.
The use of these systems is more common in large, lit commercial buildings with at least 50,000 square feet of floorspace.
One of the most common strategies involves only using lights when people are in a room or space. Occupancy sensors reduce lighting when rooms are unoccupied by automatically turning off or dimming lights.
Occupancy sensors were used in only 16 per cent of all lit buildings in 2015 but in 55 per cent of large lit buildings.
A more comprehensive approach called plug-load control automatically turns off lights and wall plugs when people leave a room or space.
Plug-load controls were reported in 1 per cent of all lit buildings in 2015 but in 3 per cent of large lit buildings.
A second set of strategies controls building lighting based on the time of day.
Scheduling automatically dims or turns off lights at certain times of the day. Scheduling was used in only 18 per cent of all lit buildings in 2015 but in 43 per cent of large lit buildings.
Building Automation Systems control the mechanical, electrical, and plumbing systems in buildings, but they can also control the lighting. These systems often rely on occupancy schedules rather than sensors and were reported in 4 per cent of all lit buildings and 19 per cent of large lit buildings in 2015.
Demand-responsive lighting reduces lighting by dimming or turning off lights at times of peak electricity pricing. This strategy was used in 4 per cent of all lit buildings and 6 per cent of large lit buildings.
A third set of strategies saves energy by adjusting the amount of light produced by bulbs to give just enough light to a space for the conditions or the tasks performed there.
Multi-level lighting or dimming adjusts lighting power through continuous dimming, stepped dimming, or stepped switching. These devices were used in only 7 per cent of all lit buildings but in 23 per cent of large lit buildings in 2015.
Daylight harvesting uses a lighting control and shade system to automatically dim light fixtures when natural light is available or adjusts shades so that natural light and artificial light combine to provide the desired level of lighting. Daylight harvesting was used in only 2 per cent of all lit buildings but in 9 per cent of large lit buildings.
High-end trimming or light-level tuning sets the maximum level of lighting to less than 100 per cent. Light-level tuning sets the level even lower if a room or space needs less light. These strategies were fairly uncommon, used in only 1 per cent of both groups of buildings.
Information about the penetration of LED bulbs was collected for the first time in 2012. Standard fluorescent, CFL, and incandescent bulbs are the most common bulb types found in commercial buildings.
High-intensity discharge, halogen, and LED bulbs are relatively less common in commercial buildings, lighting 5 per cent, 4 per cent, and 3 per cent of commercial floorspace, respectively.
Some spaces may be lit by more than one type of lighting, such as an office that uses overhead standard fluorescent lighting with supplemental incandescent task lights.
Standard fluorescent lighting continues to be the most widely used lighting type in commercial buildings, covering more than 70 per cent of lit floorspace in each survey since 1995.
Commercial buildings have begun to use more efficient lighting types: the portion of lit floorspace illuminated by CFLs has increased steadily, while the share illuminated by incandescent lighting has gradually decreased.
The 2012 survey was the first instance where the CFL share (13 per cent) was higher than that of incandescent lamps (6 per cent).