I'm trying to figure out how to replace some hell bulbs in our bathroom while still maintaining the necessary brightness to accomplish important feats of personal hygiene. Currently, we've got six 40-watt bulbs burning in the vanity fixture. That's a total pull of 240 watts. Before I go changing anything, I want to know how much energy it would consume over the remaining year without any modification. Here's how I figure it out:
Figure out kilowatts by dividing the wattage by 1,000: 240w ÷ 1000 = 0.24 kW
Figure out daily kWh by multiplying kilowatts consumed by the hours used: 0.24 kW × 1 hour = 0.24 kWh
Finally multiply kWh by the remaining days in the year: 0.24 kWh × 346 days = 83 kWh/yr
That's a LOT of energy for brightening up just one room for an hour every day. There's got to be a better option...