Past studies at Lawrence Berkeley National Laboratory (LBNL) have indicated that one of the larger lighting energy users in hotels is bathroom lighting in guestrooms. Research also indicated that 75 percent of the energy used in the bathroom occurs from lights being left on for one hour or longer.

The LBNL studies with the hotel industry have also indicated that night lighting and safety are significant issues that have compromised some of the early energy efficiency attempts. Occupancy sensors could potentially save significant amounts of energy in these hotel applications. It is also expected to see large potential savings in institutional applications (university dorms). However, these retrofits have been avoided, as hotel operators/managers are reluctant to create customer dissatisfaction or safety issues.

Research at LBNL also suggests that 50 percent energy savings could be achieved by using set points for the occupancy sensor of one hour. Using a very long set-time (the time that the sensor turns off the lamp after not detecting any movement) virtually eliminates any possibility of false offs that would impact customer safety or satisfaction. With this set time the technology becomes essentially transparent.

Another issue that came up in the early research was that bathroom lamps are used as night lighting systems so the guest can navigate to the bathroom at night. In these situations occupants are leaving the bathroom light on all night and closing the bathroom door to achieve the desired level of "dimming." While initial data did not support this as a major energy user, it is a factor in the development of a viable retrofit approach. Many hotel managers recognize the importance of this issue and are now considering explicit night lighting options.

In terms of new construction and major renovation, a significant cost of the bathroom lighting system is a function of the build-out (wooded trim encasement often with a baffle or diffuser) and installation, which is typically done on a custom basis. This presents significant cost issues and limits the amount of money available for more expensive energy saving components. It is proposed to develop a unified system that incorporates an "out-of-the-box solution" that integrates the installation the fixture, lamps, controls and night lighting into a single product that bolts into the bathroom without requiring an expensive build-out. This approach would unify the lighting and the application and potentially leads to large reductions in build-out costs. This would leave proportionally more of the lighting budget for efficient technologies. By addressing the build-out, wiring, controls and illumination functions as one system, it is hoped to overcome some of the cost barriers normally associated with retrofits in these applications.

This bathroom lighting system would integrate a series of emerging LED technologies into a conventional fluorescent system to have the options of night lighting at significantly less energy. There are two technologies to be developed in this project:

1) a new controller for hotel and institutional bathrooms, and

2) a new luminaire for hotel /institutional bathrooms.

LBNL is currently working with The Watt Stopper to refine their existing prototype version of the controller. The prototype is a version of a wall mount occupancy sensor that is not dissimilar to some of their other commercial products, but is unique for its nightlight feature. Their current prototype uses white and/or amber LEDs that illuminate the occupancy sensor lens whenever the controlled fixture is turned off. This prototype still needs refinement, including, but not limited to, optics and source work on the nightlight, electronic components, and packaging before it will be ready for field-testing.

Currently, hotel bathrooms use simple switching of their bathroom fixtures. Occupancy sensors are not currently used in these applications and timer switches are very rare. Some hotel guestrooms employ low-wattage (five W) incandescent nightlights in their bathrooms, but these too are rare. Currently hotel bathrooms have a standard four-foot linear fluorescent strip fixture installed over the mirror with a build-out around it. In some applications, fluorescent luminaires or incandescent vanity luminaires are installed without a build-out.