Home & Garden

Ask Angie: Fluorescent lights always on? That's a waste

Angie Hicks
Angie Hicks MCT

Dear Angie: Some of my physician co-workers in the radiology department at the hospital leave the overhead fluorescent lights on in their administrative offices all day, even though they spend 90 percent of their time away from these offices working with patients, reading scans, etc. I have heard that it uses more energy to turn the lights on and off a few times a day than to leave them on all day. I find that very hard to believe. I wish they would turn off the lights when they leave their offices. What are your thoughts? — Scott S., Lexington

Dear Scott: Tell your co-workers it's time to turn off the lights. It's been a longtime urban myth that turning on and off fluorescent lights uses more energy than leaving them on.

In fact, the Electric Power Research Institute debunked the notion with a study that revealed it makes sense to leave the lights on only if someone is leaving the room for three to five minutes. The reason for this is because the electronic ballasts and lamp combination draw a higher level of current at startup (when you turn the light on), but this additional energy lasts for only a fraction of a second.

Frequently turning a light on and off would reduce its life and use a lot of energy, but so does leaving the light on all day. If someone leaves the room longer than those few minutes, it is more cost-effective to turn the lights off.

One way you could try to manage this situation without interoffice conflict is to install motion sensor light switches. Motion sensor lights can be customized to the users' requirements. When people leave the office, the lights will go off after a certain time. Some manufacturers have made switches that allow the user to define how long that lag period is.

There are two common types of sensors: An occupancy sensor detects when someone enters a room and turns on the lights, then turns them off when the room is vacant. Though occupancy sensors can reduce the lamp life as measured in total hours because they power on and off more frequently, they will extend the overall life in terms of replacement because the lamps operate only during when they are needed, and the energy savings ultimately will outweigh the replacement costs. Vacancy sensors detect only when the room is vacant and will turn off the lights after the designated lag time.

Often, these sensors can be installed in the space of the existing light switch with minimal investment. Most sensors cost about $30, but the energy savings will offset that cost quickly.

Another way to look for energy savings is to ask your facility manager to contact your local utility for an energy audit, or to hire an independent auditor. Energy auditors can determine ways the facility is wasting energy and provide solutions to reduce energy use. You also can check into groups that work specifically with health care organizations on minimizing their environmental footprints.