Automatic shut-off controls are a robust technology and offer cost and energy-saving advantages without the difficulties of dimming control systems. However, automatic shut-off controls do have some limitations that need to be addressed.
Market penetration in renovation projects is low
Automatic shut-off controls are becoming commonplace in new construction; estimates from one controls manufacturer indicate that 60% of commercial projects now utilize them. However, according to the Energy Information Agency, during the 1990s new construction represented less than 10% of both buildings and floor space in the 1995 buildings stock. Penetration in existing buildings is poor due to wiring difficulties, costs to replace already-purchased manual controls, the need to redraw electrical plans, lack of energy code provisions for existing buildings, and perhaps the greatest barrier, the "hassle factor" of redoing lighting and controls systems.
Reliability of lamp/ballast systems is questionable
Early lamp failure due to frequent switching could create a barrier to the use of automatic shut-off controls. Building automation systems, panel controls and timers usually are not configured to switch lamps frequently. However, occupancy sensors set for short time delays and located in frequently used locations such as stairways, large restrooms, and hallways could cause frequent switching and therefore, shorter lamp life.
Occupants are annoyed by the absence of manual control
No technology is completely foolproof, meaning that a local, manual override is essential for any automatic strategy. In general, automatic switching should be used to turn lights off only; manual controls should be used to turn lights on when needed. This eliminates occupant annoyance. However, engineers and facility managers seem hesitant to provide manual overrides because it is assumed that they will be used too often, negating the purpose and possible energy savings.
Proper installation guidelines and help are not available
The hassle factor associated with automatic shut-off controls, particularly with occupancy sensors, may be a result of poor sensor positioning in the space, the wrong choice of sensor for the application, poor product labeling, a lack of commissioning settings on sensors, or the complexity and uniqueness of the installation. This points to the need for simpler guidelines for installers and better instructions and interfaces from manufacturers.
Incremental costs overshadow potential energy savings
The higher incremental costs of automatic shut-off controls are difficult to justify without concrete expectations about potential energy savings. Organizations and market transformation programs that could provide incentives for automatic shut-off controls will not do so until they have adequate information to predict expected savings.
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