Average Annual Energy Savings of Switching to a T8 Fluorescent Light

A row of light bulbs.

If you want to save a lot of money on your home electricity power bills, you should consider installing energy-efficient T8 fluorescent light bulbs and fixtures. It's sometimes difficult to visualize just how much money these light bulbs will save you every month, and how the savings really add up over the course of a full year. This article will demonstrate to you just how much of your hard-earned money you can save by switching to T8 fluorescent lights in your home.

Savings Comparison - Electricity Usage

Before we begin our analysis of the savings a T8 light bulb can provide, we must first establish a few facts. On average, older 40-watt light fluorescent light bulbs that use a ballast (like the older T12 tube type bulbs) produce between 2000 to 2500 lumens of light for each bulb. On the other hand, a T8 light bulb can produce about the same level of brightness while only consuming about 25 watts per hour. This is a reduction of just under 40 percent in the amount of power required to operate the light.

For screw-in light bulbs, the difference is even greater. A 40-watt incandescent light bulb produces about 450 to 500 lumens of light in most cases; while a screw-in T8 bulb can produce the same level of light and use only eight to 10 watts. This results in savings of 75% to 80% in the amount of electricity needed to run the light.

Average Electricity Costs

Although up-to-the-minute cost figures are not always available, the Department of Energy does publish a report on the average price of electricity in the United States. As of the April 2009 report on the average cost per kilowatt-hour for electricity in the United States, the national average was 12 cents per kilowatt-hour. Depending on where you live in the country, the price can vary considerably. For instance, the average cost per kilowatt in North Dakota is only 7 cents. However, the cost in Hawaii is a staggering 26 cents per kilowatt-hour.

T12 and Incandescent Light Bulb Energy Usage

A kilowatt-hour is defined as the use of 1000 watts of electricity in an hour. Therefore, a 40W T12 light bulb would cost an average of 12 cents for every 25 hours of use (25 x 40 equals 1000 watts, which equals 1 kilowatt). Since T12-type fluorescent lights use as many as four light bulbs, the figure is multiplied times four. For instance, a T12 fluorescent light with four bulbs would consume one kilowatt of power in approximately 6.25 hours. Likewise, a 40W incandescent bulb would consume one kilowatt of power in approximately 25 hours of usage. This too would result in an average cost of 12 cents.

T8 Light Bulbs and the Savings

Since T8 light bulbs with a ballast use approximately 40% less electricity than their T12 counterparts, they can be used for considerably more hours before the one-kilowatt threshold is reached. A 25W T8 bulb could be used for 40 hours and consume only one kilowatt. This means that you can use the T8 bulb 15 more hours than you could the T12 type while paying the same amount.

The screw-in type T8 light bulbs produce even greater savings. A 10W screw-in T8 light bulb could be used 100 hours versus the 40 hours with the T12 type while only consuming 1 kWh.