What Is the Typical Payback for a Sustainable Lighting Investment?

By Jeff Brain | March 12, 2015

Making a change as simple as replacing out-dated, inefficient lighting with newer, sustainable lighting systems can save individuals and companies a substantial amount of money--so much that the investment will pay back the initial cost of buying and installing the new equipment. But where do the savings come from? And which sustainable lighting products will have the quickest return on investment?

5 Sources of Savings

1. Wattage

Switching from a less efficient light bulb to a more efficient light bulb will reduce the number of electrical watts needed to power the bulb and reduce the electricity bill. For example, when you compare the wattage of incandescent, compact fluorescent (CFL), and LED bulbs in order to generate a light output of 800 lumens, a 60 watt incandescent bulb or a 13 watt compact fluorescent bulb is necessary, while the same brightness can be produced by a 6 watt LED. Since the fewer the watts used, the less electricity is consumed, the LED bulb is most efficient of the electric bulbs. Additionally, skylights and daylighting devices rely entirely on the sun as the source of illumination, creating significant savings since they do not consume any watts at all.

2. Heating and Cooling

Bulbs that use fewer watts also emit less heat. While incandescent bulbs emit 85 btu/hour, CFLs emit 30 btu/hour, and LEDs 3.4 btu/hour. Inefficient electrical lighting is a major producer of heat. It is the largest source of heat gain inside of a commercial building, so updating to more efficient electrical light sources will reduce HVAC cooling and maintenance expenses. Skylights and daylighting devices are notorious for generating heat gain. There is, however, new insulation, glazing, and control technology that can reduce and in some cases prevent heat gain.

3. Lifespan

The lifespan will determine how long a light source can be used before it will need to be replaced. Incandescent bulbs typically have a lifespan of 1,200 hours, CFLs have a lifespan of 8,000 hours, and LEDs have a lifespan of 50,000 hours. Although the more efficient bulbs are also more costly, the longer lifespan will translate into savings as they continue to endure over longer stretches time. In the time it takes for an LED light to fail, thirty to forty incandescent light bulbs will burn out. On the other hand, so long as skylights and daylighting devices are manufactured with durable materials, they can last for many years. Dramatic weather changes and harsh environmental conditions can reduce the lifespan, so check with the manufacturer to make sure the skylight or daylighting device is long-lasting. A trustworthy device will be life-cycle tested by a third-party organization and approved for extreme weather conditions, providing continued savings for 30+ years.

4. Productivity

Electrical light sources that simulate the color-changing, full spectrum qualities of the sunlight have been shown to increase worker efficiency and productivity. Unlike dull fluorescents which have a flicker effect that depresses and drains workers, full spectrum incandescent and LED bulbs energize workplaces. High quality full spectrum light has been proven to improve worker’s health and morale, encouraging better performance and helping workers see the physical details of their tasks more clearly so there is less likelihood of accidents or mistakes. Sunlight is the best stimulus for productivity. It has been known to increase feelings of wellbeing, reduce absenteeism, and is generally preferred by workers. One study conducted by Carnegie Mellon University found that proper daylighting could increase productivity by $2,475 per employee.

5. Sales

High quality light is also widely known to increase sales. It renders colors more vividly, draws the eye to specific sales displays, and makes customers feel more comfortable. Lighting is one means of defining a brand’s image. Artificial lighting upgrades can potentially increase sales by 15%, and daylighting influences purchases to an even greater degree. One PG&E analysis at a retail chain found that daylit stores experienced 40% higher sales than non-daylit ones. Studies also show that many customers are more willing to drive out of their way to shop at a daylit store than a non-daylit one.

The Payback

Incandescent bulbs and CFLs have the potential to be paid back in less than a year. Due to their high purchase price, the payback for LEDs is more than six years, but as the price falls--and it is falling rapidly--the payback period will proportionately decrease.

The payback period of skylights and daylighting devices vary depending on the type of device and its placement on the building. Traditional skylight illumination is hard to measure because it relies on the sun’s location for light, and if it is improperly placed on the roof, then the skylight will either be too dim, or conversely, too bright and hot, making it an inefficient option.

More advanced skylight and daylight devices have features which control these variables, and so their payback is more easily measured. Prismatic skylights have a payback period of 16 years, and tubular skylights have a payback period of 19 years. Active solar-tracking skylights can be paid back in 2-4.5 years.

To learn more about the SunTracker, an active solar-tracking skylight manufactured by Ciralight Global Inc., visit our website or contact our sales team today.

image credit: Giant Swarm/Flickr


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