Energy Consumption & Conservation: Home Lighting

This post is part of a series on energy consumption and conservation.  For other posts in this series please click here.

Home Lighting

According to the 2009 EIA report, thirty-two percent of the total household energy usage by Pennsylvania residents was consumed by appliances, electronics, and home lighting. This was slightly lower than the national average (35%), but slightly more than the average for the Mid-Atlantic region (29%).

Making wise choices regarding lighting in our homes can go a long way in reducing our overall energy consumption. Recent developments in technology have led to much more energy-efficient and cost-effective methods of home lighting.

Incandescent light bulbs were the standard for decades; however, new options have hit the marketplace, highlighting the short lifespan of incandescent bulbs. Not only are consumers forced to purchase more bulbs more often, but they are also very inefficient, resulting in higher electricity costs.

Compact Fluorescent Lights (CFLs) were introduced in the mid-1980s, but were large and very expensive. Since then, many improvements have been made, allowing CFLs to become much more cost-efficient. They use approximately 75% less energy compared to incandescents and last approximately 10 times longer, making them a much smarter choice for home and business owners alike.

The newest development in home lighting is the introduction of light-emitting diodes (LEDs). As with all new technologies, prices generally fall as time goes on and new improvements are developed and introduced; such has been the case with LED bulbs.

[1]According to the U.S. Department of Energy,

“Since 2008, the cost of LED bulbs has fallen more than 85 percent, and most recently, a number of retailers announced that they will sell LEDs at $10 or less. Today’s LED bulbs are also six to seven times more energy efficient than conventional incandescent lights, cut energy use by more than 80 percent and can last more than 25 times longer. Taken together, these advancements have led to rapid deployment in the past of couple years in both commercial and residential applications. In 2012 alone, more than 49 million LEDs were installed in the U.S. — saving about $675 million in annual energy costs — and as prices continue to drop, LEDs are expected to become a common feature in homes across the country.”

Another benefit provided by LED lighting is the lack of mercury that can be found in CFL bulbs. Mercury is an element that is poisonous to humans, and when ingested can cause negative health effects. While the amount of mercury found in CFL bulbs is relatively small – generally 4 milligrams per bulb – this is yet another reason to consider purchasing LED lights.

If you have CFL bulbs that need to be disposed of, it’s important to understand the proper steps to ensure that mercury is not released during the process, resulting in injury to yourself or damage to the environment.

Recycling used CFL bulbs prevents the release of mercury into the environment and also allows other materials inside the bulbs to be re-used. To find the recycling center closest to you, visit

[2]According to the U.S. Department of Energy, “LEDs contain no mercury, and a recent Energy Department study determined that LEDs have a much smaller environmental impact than incandescent bulbs. They also have an edge over compact fluorescent lights (CFLs) that’s expected to grow over the next few years as LED technology continues its steady improvement.”

With this new information, it is clear that utilizing old-style, incandescent light bulbs is neither cost-effective nor energy-efficient, making it a near obsolete technology. When the need for home-lighting purchases arises in the future, consider purchasing LED bulbs.

If you need even more incentive, by using some simple math, we can put a rough dollar amount on how much you can save by switching to more efficient lighting sources.

[3]According to an Xcel Energy blog post,  the average American household uses 47 light bulbs. If we assume that all bulbs are of the 60 watt variety – for sake of comparison – using CFL or LED bulbs use drastically less energy.


All bulbs deliver equal brightness Single bulb wattage Wattage used for whole house
Incandescent 60 watts 2,820 watts
CFL 14 watts 658 watts
LED 9.5 watts 446.5 watts


The average cost of electricity in Pennsylvania is 13.18 cents per kilowatt hour (kWh). And let’s just assume that your lights are on for 5 hours a day, meaning 150 hours in a typical month. Now let’s plug our information into the formula used on the Xcel blog.

kW used X (Cost per kWh) X Hours Used = Monthly Lighting Costs

Remember, a kilowatt (kW) is 1,000 watts, so we divide our wattage by 1,000 for this formula.

Monthly Cost of Using Incandescent Light Bulbs

2.820 X $0.1318 X 150 hours = $55.75

Monthly Cost of Using CFL Bulbs

0.658 X $0.1318 X 150 hours = $13.01

Monthly Cost of Using LED Bulbs

0.447 X $0.1318 X 150 hours = $8.84

As you can easily see, not only are energy-efficient light bulbs (CFLs, LEDs) financially beneficial for you as a consumer, they can also have a large positive effect on the environment by slashing the use of electricity, and thus, eliminating the need for coal-burning electricity manufacturing.

[1] Matulka, Rebecca; Wood, Daniel. The History of the Light Bulb. U.S. Dept. of Energy. 22 Nov. 2013. Web. 14 Nov. 2014. <>

[2] Matulka, Rebecca. Top 8 Things You Didn’t Know About LEDs. U.S. Dept. of Energy. 4 Jun. 2013. Web. 14 Nov. 2014. <>

[3] “How Much Money Can You Save by Switching to Energy-Efficient Light Bulbs?” Web log post. Connect. Xcel Energy, 19 Feb. 2014. Web. 24 Feb. 2015. <>.