 3 Steps In Calculating Electricity Usage Cost Of Home Appliances

Every electrical appliances and device in our home collectively contribute to our electricity consumption as reflected by a single number in our electricity bill, which is the total usage in KWH or kilowatt-hour.

Have you ever wondered how to calculate the cost of electricity usage of a particular device? How much is the power consumption of my aircon and how much it cost? How costly it is to use a tumble dryer or a dishwasher?

If you are renting a room, most likely you have come across a room rental where the utilities are included in the rent, except for electricity charges. The next question, how much will it add up to the rental?

And if you are planning to save electricity, first step is to get to know your electricity usage. Here is a simple guide on estimating the cost of electricity for each device.

1. Get the wattage of your appliances or devices.

Most appliances and devices come with a label attached, some specify the model number, where it is made and the wattage of the device. Most labels are found at a corner, at the back or under the device. If you have difficulty locating the label, another option is to find out from the manufacturer website or user manual where most of them provide a full specification. Maybe a quick Google search for a similar item for a rough idea of the wattage.

Here is a list of common home appliances and its wattages, where we took from a few electrical types of equipment for a rough idea. The range of wattage is far more varied from the list given, as each device or model has different specs. Be sure to check the labels or from the manufacturer for a more accurate one.

2. Estimate and compute usage in kilowatt-hour, KWH.

To compute usage in KWH of a device, you need the wattage. Once you get that number by either reading the label or from the manufacturer manual, you just need to multiply the watt with the number of hour of usage per day. That would get your usage in watt-hour per day, Wh/day

Since the cost of usage is measured in KWH, the next step is to convert it by dividing by 1000. Now, we know the KWH usage in a single day of that device. To get the usage in a month, just multiply it by the number of days. In this example, we use 30 days in a month.

Therefore, the formula for usage in KWH for a month would be,

KWH usage for a month = Watt (W) X Number of hour a day (hr) / 1000 X 30 days

KWH usage for a month = W x hr / 1000 x 30 days

Example,

An aircon with 1000 watt, turned on for 8 hours a day for a month, KWH usage would be,

1000 x 8 / 1000 x 30 = 240 KWH for the month

3. Calculate the cost of usage.

Lastly, how much do you need to pay for the month for that device? To get the cost, you will need to find out what is the charges for a single KWH. It might be RM0.50, RM0.60, or maybe RM1.00 per KWH. Just check with your landlord to get the charges and multiply it with the KWH usage in a month.

Cost per month = KWH usage in a month X price per KWH

Example,

The cost per KWH is RM0.50, therefore, applying it to the example earlier,

240 KWH x RM0.50 = RM120

So, the cost for using the 1000 watt aircon for 8 hours a day, for a month would cost you RM120.

Now, here is the full formula in a single line,

Cost per month = Watt (W) X Number of hour a day (hr) / 1000 X 30 days x Price per KWH (p)

Cost per month = W x hr / 1000 x 30 x p

Now, to get the total bill that you need to pay, you just need to apply the formula to each and every device that you use.

Let us use an example to compare our daily purchases to the number of hours we can keep common electrical equipment running.

Example,

Using our previous example of running an aircon of 1000 watt, at KWH rate of RM0.50. How many hours we can keep an air conditioner running?