Looking for a quick way to reduce energy and maintenance bills? Exit signs that must be lit 24 hours a day, 7 days a week can take a bite out of commercial and industrial budgets, but today’s more efficient exit signs can offer lifetime savings of up to $300 per sign in reduced energy, materials, and labor costs as compared with standard incandescent models.
The Energy Policy Act of 2005 requires that all exit signs manufactured after January 1, 2006, comply with version 2.0 of the Energy Star program requirements for exit signs. This version of the specification requires that exit signs draw no more than 5 watts (W) per illuminated face of the exit sign, thus eliminating not only incandescent but also fluorescent light sources from contention. Effective May 1, 2008, the U.S. Environmental Protection Agency (EPA) has suspended the Energy Star specification due to the new minimum federal standard.
Incandescent lamps. In traditional exit signs, two incandescent lamps typically light the sign. They draw 24 to 40 W of power (Table 1), so depending on local prices, a single exit sign can run up electricity bills of more than $30 per year. More importantly, exit signs are required to be on all the time and therefore the lamps burn out in a matter of months. The cost of replacement lamps and the labor to install them can add up to $24 per year per sign, not to mention increasing the risk of having a sign out of order at the wrong time.
Today, the most cost-effective alternatives are the newest light-emitting diode (LED) exit signs (Figure 1). They use only 1 to 5 watts of power and cost less than $5 per year to operate, depending on the model and local utility costs. Replacing an entire incandescent exit sign with an LED unit can cost anywhere from $30 to $250, depending on the style of sign. Because LEDs also last considerably longer than incandescent lamps, lifecycle savings are dramatic. Over a 10-year period, first costs, energy expenditures, and maintenance requirements for an incandescent sign could run about $570, depending on local conditions, whereas a comparable LED unit with a 10-year life would incur overall costs of about $125.
Another option is to retrofit an existing incandescent sign with LED light strips. Retailers sell white LED light strips that screw into the incandescent interface in an exit sign. These strips cost $20 or less for a two-“bulb” set. Although this type of strip saves considerable energy and money, it is important to note that the light is still being filtered, so energy savings are not as high as they would be if the whole sign was replaced.
Electroluminescent panels. These panels (Figure 2), also known as light-emitting capacitors (LECs), feature phosphors that light up when voltage is applied. Although the panels produce a uniform light and consume only 0.25 W of power, some products are costly and their brightness can decline significantly over time.
Photoluminescent materials. Some exit-sign manufacturers use photoluminescent materials that absorb and reradiate light. These signs do not require electrical power, but they need to be charged by light sources in their surrounding area. Improvements in the technology have led to acceptance by the National Fire Protection Code and recent UL approvals for some photoluminescent products. These products must maintain particular levels of visibility for at least 90 minutes after other sources of light have been extinguished.
Select an energy-efficient sign. The U.S. government has passed a minimum federal efficiency standard for exit signs. A sign must:
Manufacturers test their products against these requirements. You’ll find that most of the qualifying signs are made with LEDs. The standard also allows self-illuminating signs such as those that use photoluminescent materials.
To hone in on the most cost-effective option for your application, we recommend using the Energy Star exit sign calculator, which compares annual and life-cycle costs of energy-efficient LED and photoluminescent exit signs with antiquated incandescent exit signs.
Pick products that use the newest LED technology. Not all LED products offer equal performance. Exit signs using the newest LED technology start out brighter and maintain their brightness longer than those using older technologies. For red exit signs, look for products that use aluminum, indium, gallium, and phosphorus LEDs, referred to in the trade as AlInGaP.
Don’t be fooled by long warranties. LEDs rarely burn out, but their brightness does fade over time, depending on the materials they are made of and the temperatures and humidity they are subjected to. In some applications, the brightness of a sign may diminish in just a few years to the point that it no longer meets code. Even so, in the past, many manufacturers offered long warranties on their products—in some cases for 25 years or more. Buyers often purchased the products with the expectation that they would last for the life of the building without any maintenance.
Although the newest LED products are expected to last longer than earlier signs, reputable manufacturers are now offering shorter warranties. Lithonia, for example, which uses the longest-lived LEDs available, backs up many of its products with a 5-year warranty. Lithonia believes the LEDs will last longer than that, but given that no 25-year tests have been conducted, the company did not want to mislead buyers.
Are green LED signs a viable choice? Green signs are preferred (or required) in some areas, but they are not permitted in Canada. (In Canada, standard CSA 860 covers the size, shape, and intensity of exit signs.) Early green LED products provided lower light output than red LED signs, but new technology has created a green LED that is both bright and efficient. This technology is now available in products made by such companies as Gilbert Industries and Lithonia.
LED exit signs will likely continue to be the most cost-effective, energy-efficient option so long as prices keep falling and performance is improved. By one estimate, LEDs already account for more than 90 percent of national exit-sign sales. LEDs with efficacies greater than those of CFLs have already been tested in the laboratory. The growing use of LED technology in other applications (such as traffic lights and outdoor signage) should accelerate the introduction of new products in the exit sign arena as well. Research continues to produce improvements in photoluminescent and electroluminescent technologies as well.