1. Comparing Efficiency VS

2. EnerGuide and Energy Star Labels
When buying an electrical device it is important to consider three things:
the price of the device
the cost of operating the device over time.
The environmental impact of the device
EnerGuide labels provides consumers an estimate of how much electrical energy (measured in kWh) the appliance will use in one year.
The Energy Star® symbol is used to identify products that meet a minimum level of efficiency.

3. Cost of Electricity/hour
Cost and Energy Comparison
60 W Incandescent Light Bulb vs. 7 W LED Bulb (60 W Equivalent)
Device
Power
(kW)
Time
(h)
Energy Rating
(kW·h)
Cost of Electricity/hour
($)
Cost to run device/day
Cost/bulb
60 W incandescent bulb
0.06 8
0.480
0.14
0.0672
0.90
7 W LED bulb
0.007
0.056
6.00

4. Difference between cost of bulbs = $6.00 – 0.90 = $5.10
Difference between cost of electricity/day = $ – = $
Time to get bulb cost back
Difference between cost of bulbs = difference between cost/day x time (days)
$5.10 = x time (days)
time (days) = 5.10/
= 85.9 days
It would take about 86 days of usage by the 7W LED bulb to recoup your costs.