Simple formula helps calculate power hungry culprits
The following formula helps to work out the estimated power use, and cost, of any appliances in your home. And you don’t have to go through the cost of installing even the simplest plug-in monitor.
Start out with the watt value of an appliance (usually marked on the appliance itself). Then apply the following formula:
watts (of your appliance) x hours used per day ÷ 1000 = the daily kilowatt per hour (kWh) usage
Once you have this information, you can multiply the kWh by your cost per kWh (use a cost that includes electricity authority levies but excludes daily charges).
For example: 1000 watts (average clothes iron) x 0.25 hours per day ÷ 1000 = 0.25 kWh per hour x 27 cents per kWh (theoretical electricity supplier’s price) = 6.75 cents per day.
In effect, your ironing is costing you on average 47.25 cents per week (about a $1.89 per month).
For more information about watts used by various appliances, visit Otago University Energy@Home