LED Bulbs save Big Bucks on the Electric Bill
By: Joe J Wallace
I became sidetracked during the design of a rooftop solar system and the cost associated with it by the thought of, just how to reduce the price of a solar photovoltaic system by implementing the hardest hitting efficiencies available to reduce electricity use. Enter the emerging innovation of the light emitting diode (LED) light bulb.
LED’s have been around for years and are the light source used to read compact disks and DVDs. Recently the LED has been refined to the point that light bulbs that utilize an array of LEDs to produce light have become not only affordable but a great way to reduce your use of electricity.
To explore just what a single LED bulb can save and the payback time associated with buying a $30 light bulb, the first step is to assume a cost per kilowatt hour. For the purposes of this analysis a cost of 16 cents per kWh was used to be consistent with local utility rates.
For one typical light bulb in a heavy use area like a living room or kitchen, replacing it with an LED with an equivalent light output the savings is roughly 9 kWh per month. This savings at 16 cents per kWh translates into a saving of $1.44 per month per bulb based on only 5 hours a day of on-time. For lights that are on 24 hours per day that number increases to $6.91 per month.
The energy savings alone then has a payback time of only 20 months for typical use areas of a home but come down to only 4.3 months for 24 hour on applications like security lighting. That translates into a return on investment of over 50% in typical use areas and nearly 300% in 24 hour applications.
The other money saving advantages offered by LED lighting are the fact that they are rated to last more than 20,000 hours saving on replacement bulbs and they do not add heat to a room as conventional bulbs do saving on air conditioning costs.
LED lighting as an energy saver is a great investment. In the application that was the subject of my design, the home has 40 bulbs in it that calculated an energy savings of 3,240 kWh per year. For the prevailing electric rates in SW Indiana this would produce $518.40 per year ($43.20 per month) in energy savings.
The real positive upside of this savings came to the homeowner through analysis to understand how much less solar photovoltaic generation would be needed on the home. In Southern California where this project is taking place putting in $1,000 worth of LED bulbs have been projected to eliminate the need for 2,000 Watts of Solar PV capacity. The typical price of Solar PV system installed is about $5.50 per Watt or $11,000 for the 2,000 Watts eliminated from the system. Even with the 30% federal tax credit the use of LED bulbs will save this homeowner $7,700 on a new Solar PV system in addition to the monthly savings on the electric bill.
