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We have seen estimates suggesting that LED’s use an average of 80% as much energy as an equivalent CFL. Using this conversion (or another of your choosing) you could model each LED bulb as 0.8 of a CFL bulb. The control will handle a fractional entry even though it doesn’t display the digits. You will obviously have to edit the cost manually as well.
Please provide an example, since the percentages are in number of lights, not amount of energy used per light. So if a home has 100 lamps, of which 25 are currently 13 Watt CFLs, and we want to recommend that 10 75 Watt incandescent lamps be replaced with 9 Watt LEDs . . . reducing the number of recommended CFLs to 8 (80% of the number of lamps) increases the end value of the amount of energy used. Or, how do we input 10 CFLs be replaced with 10 LEDs?
Thanks!
Before I address your examples, I will give you a little more detail on our model. Our model is based on a Lawrence Berkeley study, which found that the average incandescent light bulb was 67 watts and ran for 2.1 hours per day. The leads to an average annual consumption of 51.4 kWh/yr for incandescent bulbs. We assume that the average CFL consumes 25% as much energy (i.e. 16.75 watts). We are looking into adding a detailed lighting survey as an alternative to this model.
For your first scenario, you are replacing 10 incandescent bulbs with LEDs. Here is a simple approach :
- Base: 75 Incandescent, 25 CFL
- Improved: 65 Incandescent , 32 CFL
- I removed 10 incandescent and added 7= 10*9/13 CFL
If you have actually checked the wattage of each bulb in the house, you could convert each bulb count using the ratio of actual wattage to assumed wattage for each bulb. In that case initial counts would be 84=75*75/67 incandescent and 19=25*13/16.75 CFL. The final counts would be 73=65*75/67 incandescent and 24=19+5=19+10*9/16.75 CFL.
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