Different home appliances take-up different power consumption depending on its composition and the service it renders. Now that the natural sources of energy are in the midst of depleting, people also suffers from depleting budget to cope up with the ever increasing kilowatthour rate. It is a good thing to know the details of each common household appliance and how to compute the consumption rate based on the details given.
Below are some of the usual household appliances and their approximate wattage (power) consumption: (Note: this is just a mere approximation; the exact value ranges but near more or less)
Common Household Appliance |
Power Consumption (Watts) |
Air Conditioner |
1000-5000 |
Blow Dryer |
800-1000 |
Compact Fluorescent Lamps (CFL's) |
11-30 |
Coffee Maker |
800 |
Computer (Desktop) |
80-150 |
Computer (Laptop) |
20-50 |
Electric Fans |
10-50 |
Flat Iron |
1000 |
Home Theater |
50-2000 |
Incandescent Lamps |
40-100 |
Microwave Oven |
600-1500 |
Refrigerators |
475-540 |
Toasters |
800-1500 |
TV Sets |
70-150 |
Washing Machine |
300-500 |
If one tries to analyze the approximate figures given, those appliances that are likely to give-out or produce heat requires a far higher value than those that were not. It is advised to turn those off and at the same time unplug it to further save on power consumption. One common misconception about the term “standby power consumption” is the fact that it consumes almost negligible power when in fact it does not!
Standby current or quiescent current is the current consumed by the internal or external power supply of a certain appliance when it is at its idle state that can still consume from 0% to 100% of power. Some of the paid power losses are connected to this. Difference in standby current lies on the type of appliance, its feature, designs and components. Some appliances consume the same amount of power when it is turned-ON or turned-OFF; definitely no change at all, although some are just equal.
Steps were taken into consideration to come up with things to make power savings move further. Concerning the wasted power due to standby or idling current, there are two suggested methods that are basically opted to minimize standby power consumption. The two can either be technical or behavioural. The first method concerns the participation of manufacturers and developers of certain appliance. Redesigning a circuit through eliminating or substituting some components to reduce power consumption is also an option aside from re-inventing or incorporating new technology that focuses on power saving. The second method, however, is concerned on how a certain consumer justifies and exercise power reduction scheme such as turning appliances OFF. This behavioural method can sometimes be inappropriate especially if the appliances concerned needs to be connected (though at an idle state) to make communications of interconnected appliances open all the times. This may include computers and some appliances or gadgets that have programmable timers and clocking circuits incorporated. Whatever which, these may not always be the most practical solution.
Basic knowledge in computing the power consumption is also a step that can move a consumer forward into making intelligent judgement on choosing or employing a certain appliance. Below is the mathematical computation:
1. To compute the Instantaneous Power (Pi):
The instantaneous Power (Pi) of a certain appliance is the amount of power used at a point in time. This is measured in watts (W). This is a usually indicated parameter in every appliance.
Given: Voltage requirement (volts)
Current requirement (amperes)
Pi = V * I (watts)
2. To compute for the Power used over a period of time (Pt):
This is the amount of power consumed for a certain period of time a certain appliance was used. This also depends if the appliance have a constant or varying load. This is expressed in the unit kWh or kilowatthour. This is the value we usually look for aside from the monetary bill in our monthly electricity bill.
For constant load:
Given: Pi or the instantaneous power usually labelled in the appliance (Watts)
t or time that a certain appliance is operating (hours)
Pt = Pi * t (kWh)
For varying load:
Given: Pi or the instantaneous power usually labelled in the appliance (Watts)
tv, estimated roughly but near to accurate (hours)
Pt = Pi * tv (kWh)
One good example of varying load is the power consumed by a refrigerator considering that the compress or remains ON for only a fraction of an hour the refrigerator is functioning.
3. To compute for the electricity bill:
This is the monthly consumption of power in monetary unit imposed and collected to the consumers by the power companies.
Given: Pt in kWh
Power Rate which is a scheduled parameter by the power companies, monetary rate per 1 kWh consumed, (monetary unit)
Miscellaneous fees (this may include environmental fees, government tax, etc)
Electric Bill = Pt * Power Rate + Pt * miscellaneous fees
In light of this power saving reduction scheme, one can greatly gain an enormous financial saving by switching from the conventional incandescent bulbs or compact fluorescent lamps into efficient LED lights. Referring to the table above, a certain incandescent bulb can consume power in a range of 40 to 100 Watts and a certain CFL can consume power in a range of 11 to 30 Watts. Consider using a 4W LED light to replace a 40W incandescent lamp, a far 36W of power is already saved and if it is used in 24 hours, an instant almost 1 kWh is already saved and slashed from the electricity bill. Aside from that, LEDs showcases far longer life than its counterpart, so aside from power cost saving, maintenance and replacement savings can also be attained.