Energy-Efficient Lighting Design: Illuminating Spaces the Green Way
Lighting is one of the easiest and least expensive ways to cut down on your carbon footprint at home. Lighting is responsible for around "6% (81 billion kilowatt hours [kWh]) of electricity consumption in U.S." homes. Switching to energy-efficient lighting can save you hundreds of dollars per year. This post will break down the various lighting options and technologies available to help cut carbon—and financial—costs.
First, a brief history of lightbulbs. Incandescent bulbs came about in the late nineteenth century, thanks to Thomas Edison. They were revolutionary at the time, but were highly inefficient, so much so that up to 90% of the energy burned was wasted as heat. Then came incandescent lights, which were the only option until the 1980s, when compact fluorescent lamps, or CFLs, became the more energy-efficient option. However, the early CFL bulbs were too large for most lamps and were much more expensive. With time, the technology improved and CFLs became more popular and commonplace. In the early 2000s, a newer and more efficient CFL that used halogen was introduced. It used between 25% and 30% less power than old incandescents. Since then, light-emitting diode—LED—light bulbs have become the most efficient option, in terms of performance and energy savings.
LEDs are a type of solid-state lighting. They use semiconductors to convert electricity into light. They use up to 90% less energy and last up to 25 times longer than traditional incandescent bulbs. Compared to CFL bulbs, LEDs use one-sixth of the energy that CFLs require to produce the same amount of light, and LEDs also last up to ten times longer. They are the most energy-efficient bulbs available and therefore offer the greatest potential for savings on your energy bills.
LEDs produce between 40 and 80 lumens per watt and have a low operating temperature. A lumen is a measurement of light output. The unit of measurement is lumens (lm), and it describes the total amount of light that is visible to the human eye from a light source. The higher the lumen count, the brighter the light will appear. One lumen is about the equivalent of the amount of light produced by one birthday candle held one foot away from the human eye.
This is not to get confused with wattage. Wattage measures the amount of energy that a lightbulb uses each hour. Higher wattage bulbs mean that the light bulb requires more energy to operate, and this isn’t necessarily correlated with the brightness, or the lumens, of the bulb. So you want to look for bulbs that offer a higher lumen count and a lower wattage requirement, which generally signifies your bulb operates efficiently, producing greater brightness with less energy.
Most LED bulbs last for around 25,000 hours, meaning if you left the light on 24 hours a day, 7 days a week, you would only have to replace your bulb every 15 years. The cost of lighting an LED bulb for 25,000 hours comes out to about $30, which is less than what it would cost to light an incandescent or CFL bulb for the same amount of time. The average lifespan of CFL bulbs is around 8,000 hours, meaning that for every three CFL bulbs, you could just have one LED bulb.
If a light bulb were 100% efficient, this would mean that 100% of the energy flowing into the bulb would be converted into electricity, with no energy lost. LED bulbs operate at around 90% efficiency, while CFL bulbs are about 85% efficient, and incandescents are just 10% efficient. The average home in America has more than 40 light sockets. If you added up all the bulbs in a home and swapped them all from incandescent to LED, you would save over $100 each year. Nationally, if every home switched to LEDs, we would see annual savings of $12 billion. So, what can you do?
Consider the costs: sure, there are some costs to be weighed in this discussion. While incandescent and halogen bulbs have already been phased out in Europe and are seeing a decline in other parts of the world as well, they continue to be manufactured in Mexico and China, for example. Up front, they can be slightly less expensive than LEDs, meaning that consumers might opt for the cheaper option on the shelf. However, incandescent and halogen light bulbs rack up a higher cost down the line. LEDs might be more expensive to purchase, but they usually pay for themselves within the first year of usage because they consume so much less energy than incandescent or halogen lights.
Choose wisely: select bulbs that have earned the EPA’s Energy Star rating. If a bulb is Energy Star rated, it means that it checks off a long list of criteria, like dimming well, not flickering, and giving off good light and color, all while complying with energy efficiency standards. When you opt for an Energy Star light bulb, you know it will be high quality and long-lasting. Keeping an eye out for vendors that use recycled materials and responsible and sustainable manufacturing practices is also a good idea.
Make some home adjustments: consider making some other swaps at home to maximize the light you get and minimize the energy wasted. Lighting controls like timers and dimmers save electricity. Use more task lighting: lighting a painting or staircase, adding in some lamps, or installing a reading light by your bed can all minimize the energy your home uses by only lighting the space you need while providing quality, sufficient light. Treating your walls as a canvas for light can brighten your home. Since walls reflect light, positioning your lighting systems strategically to the walls in a room can make a big difference. Similarly, the color of your walls can affect the brightness of a space and can change how much lighting is needed to sufficiently illuminate your home. Dark colors absorb light, while light colors reflect it, meaning that a lighter-colored room will require less lighting—and thus electricity—than a darker-colored room to achieve the same effect. When shopping for light fixtures, it can also be helpful to consider how they will serve as a vehicle for light, and what kinds of materials they are sourced and made from.
The last thing to consider is how you are disposing of your light bulbs. Whether you are transitioning from incandescent or CFL bulbs to LEDs, or just need to swap out some old lights, there are some considerations for how to pitch them. Hardware stores like Lowe’s and Home Depot offer light bulb recycling services.
