As a nation, we spend about one-quarter of our electricity budget on lighting - that's more than $37 billion annually. In your own office, lighting alone will consume 20 percent to 30 percent of your total energy bill, according to the Department of Energy. Did you have any idea lighting could have this much impact on your business's overhead costs?

It's actually the bulb that's to blame. Although inexpensive, bulbs can be a big power drain. You need to find a bulb that conserves energy and suits your office's needs. Like most businesses, you'll probably end up with fluorescent lighting - the most energy-efficient bulb on the market.

The level of brightness, or illumination, is key when choosing a fluorescent bulb. Illumination is measured in footcandles, and The Illuminating Engineering Society says that selecting a bulb that's not too bright, say 30 to 50 footcandles, is best for office work.

You want even room illumination, which means everything should be the same brightness. This is important when working with computers because light that's too bright will reflect off computer screens, creating glare. This isn't just an annoyance, it can cause serious health problems. Computer Vision Syndrome (CVS), which consists of eye and neck pain related to computer use, can be a direct result of poor lighting conditions.

To help combat CVS, you may want to provide manual lighting. Manual lighting, such as light dimmers, blinds, and task lighting (sources, such as desk lamps, that provide light just where it is needed), has a positive effect on both your employees and your energy bill, according to a 1998 report by the Lighting Research Center in Troy, N.Y.

Most of the time, employees working at computers prefer to have only a portion of the office lights turned on. But when they change to reading printed materials, they want brighter light. The study shows that giving your employees control over their own lighting not only makes them happy, it reduces your electricity costs.

Dimmers allow the light to be set at employees' preferences, and task lighting allows overhead lights to be shut off and light provided just where it's needed, which will cut down on costs. Blinds give employees an opportunity to control sunlight to their best advantage.

Pricing for the different kinds of manual lighting varies depending on quality and quantity. As far as bulb pricing goes, expect to pay about $10 to $15 per fluorescent bulb (when you buy in bulk, the price per bulb will decrease).

As much as you may love those incandescent bulbs you have in your home, they simply aren't cost-effective for your business. Although incandescent bulbs are less expensive per bulb, fluorescent bulbs last 20 times longer and use 80 percent less energy, according to General Electric.

It's easy to overlook the impact of those long bulbs, but shedding some light on this topic can help provide a healthier workplace for your employees and save yourself some money.

Quick tips