Cost per year = (unit wattage x hours of use per day x days of use per year x cost per kWh) / 1,000 Using the same figures again, the calculation would be (1,500W x 8 hours x 180 days x $0.15 ...

Fixed costs do not go down over time, but you can reduce your cost per mile by driving more miles. The difference per mile here is only 0.8 cent, which may seem like small change, but remember the ...