Energy Savings Calculator for Replacing Light Bulbs by LEDFor the industry Usage (Per month) KWh 500

Energy charge 10.5

Fixed charge 240

Charge for per unit(KWh) 10.98

Life Span (in hours) 1,500 10,000 60,000 Watts 60 14 6 Cost of the bulb LKR 45.00 LKR 400.00 LKR 6,000.00KWh of electricty used over 60k hours 3,600 840 360 Electricity Cost (@ Rs. 10.98 per KWh) LKR 39,528.00 LKR 9,223.20 LKR 3,952.80Bulbs needed for 60k hours of usage 40 6 1 Equivalent 60k hour bulb expense LKR 1,800.00 LKR 2,400.00 LKR 6,000.00Total 60,000 Hour Lighting Spend LKR 41,328.00 LKR 11,623.20 LKR 9,952.80

Calculate Your Energy Savings

No.of household light bulbs 50 50 50 Your estimated daily usage (hours) 8 8 8 Days in month 30 30 30

cost LKR 2,066,400.00 LKR 581,160.00 LKR 497,640.00Savings by switching from Incandescent LKR 0.00 LKR 1,485,240.00 LKR 1,568,760.00Savings by switching from CFL LKR 0.00 LKR 83,520.00

Monthly household energy savings

720 168 72 Electricity Cost (@ Rs.10.98) LKR 7,905.60 LKR 1,844.64 LKR 790.56 Savings by switching from Incandescent LKR - LKR 6,060.96 LKR 7,115.04 Savings by switching from CFL LKR 0.00 LKR 1,054.08

Incandescent Light Bulbs

CFL(Compact Fluorescent Light Bulbs)

LED(Light-Emitting Diode Light Bulbs)

savings over 60,000 hours (energy + replacement)

KWh used per month(wattage *#bulbs*daily usage *# months)

Energy saving by switching from incandescent 77% 90%

Yearly household energy savingsKWh used per year 8,760 2,044 876 Electricity Cost (@ Rs. 10.98) LKR 96,184.80 LKR 22,443.12 LKR 9,618.48Savings by switching from Incandescent LKR 0.00 LKR 73,741.68 LKR 86,566.32Savings by switching from CFL LKR 0.00 LKR 12,824.64

Three types of Bulbs are choosen to have 720 Lumens (Incandescent - 12lm/W, CFL - 50lm/W, LED - 120lm/W)

Comparision shows that using an LED instead of Incandescent and CFL bulbs saves energy and save money significantly

An LED only consumes about 360 KWh units for its entire life over 60,000 hrs.

By replacing an LED over incandescent bulb, save the energy by 90% where by replacing a CFL bulb over incandescent is 77%

Notes -

5. Most LEDs come with a minimum 2-year guarantee. Any defective LED bulb will usually fail within this time.

1. Cost of electricity will vary. The figures used above are from the tarrif rates of 1st January 2011 to 30th June 2011 approved by the Public Utilities Commission of Sri Lanka 2. The cost per bulb for LEDs may vary. We used the figure of LKR 6000 (for a 6 watt LED) as an average among lighting retailers. 3. Estimates of bulb lifespan are projected, since it would take about 6 years of continuous lighting to test. Some manufacturers claim the new LED bulbs will last up to 25 years under normal household use, but this is not proven.

4. Bulb breakage and bulb replacement costs have not been factored into this comparison chart. Incandescent bulbs and CFL bulbs are more easily broken than LEDs, which increases their cost of use.

Calculate Your Monthly Kilowatt-hours

Starting Month 04/2006

Month of Bill Total Energy Bill Total Kilowatt-Hours Used Average KWh Highest Rate¹April 06 $100.00 1,000 0.100 0.329 March 06 $100.00 1,000 0.100 0.329 February 06 $100.00 1,000 0.100 0.233 January 06 $100.00 1,000 0.100 0.195 December 05 $100.00 1,000 0.100 0.195 November 05 $100.00 1,000 0.100 0.195 October 05 $100.00 1,000 0.100 0.219 September 05 $100.00 1,000 0.100 0.219 August 05 $100.00 1,000 0.100 0.219 July 05 $100.00 1,000 0.100 0.218 June 05 $100.00 1,000 0.100 0.194 May 05 $100.00 1,000 0.100 0.194

$1,200.00 12,000 0.100 0.228

Put in your own rate: $0.33

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blue font = input cells

black font = calculated cells

¹ You can also put in the highest tier rate charged by your utility, figures quoted here are from SC Edison, if you lower your energy

bills, the highest rate will be the first amount to get reduced. And you will see a more dramatic difference in your savings