Appliance Electricity Usage: How to Measure Electricity Usage by an Appliance
Inspire Clean Energy
9 min read
category: Sustainable Living
Measuring your appliance electricity usage is important for finding out what in your home is consuming the most energy and possibly causing an unnecessary increase in your electricity bills. When you know how much energy your appliances and lighting is using, and costing you, you can decide when it’s necessary to upgrade to a new energy-efficient model.
In this guide, we’ll talk about how much it costs to run certain light bulbs and how you can save money on your appliances’ energy use. (If you’re interested in our unlimited clean energy plan, click here.)
How to check and measure electricity usage by an appliance
In order to check appliance electricity usage, you will need to know the wattage of each appliance. This can typically be found stamped somewhere on the appliance, on the nameplate, or on a label attached to the plug. This number actually represents the maximum amount of power that could be consumed by the appliance so it may take in lower wattage if the appliance has various settings.
If you cannot find the wattage written on the appliance, the wattage can be estimated using an ammeter to measure the current going into the appliance and then multiplying that by the voltage being used. Most US smaller appliances will use 120 volts, and larger appliances will use 240 volts.
Now you know the wattage, you can measure appliance energy usage. How to measure electricity usage by an appliance is actually very simple, you just need to use this formula for each appliance:
(wattage x hours used per day) ÷ 1000 = daily kilowatt-hour (kWh) consumption
To find the annual consumption for appliance energy use, you simply multiply this number by the number of days that the appliance is used throughout a year.
Once you have worked out the annual kWh consumption for each appliance, you can then estimate how much the appliance is costing you to run each year, by multiplying kWh/year by the rate your utility gives you per kWh.
How much electricity does each appliance use?
Each appliance in your home will use a different amount of electricity, and it is beneficial to know these figures to cut down on energy usage where you can. Here is a list of approximate electricity usage per appliance of some commonly used appliances in a home, not including the largest consumers of energy which we will go into next.
- Toaster (800 to 1,400 watts) – 0.04 kWh per use
- Coffee Maker (900 to 1,200 watts) – 0.12-0.26 kWh per brew
- Vacuum (1,000 to 1,200 watts) – 0.75 kWh/hour
- Clothes Iron (1,000 to 1,800 watts) – 1.08 kWh/hour
- Toaster Oven (1,200 watts) – 22.5 kWh/month
- Hair Dryer (1,200-1,875 watts) – 1.5 kWh/hour
What appliances use the most electricity in the household?
Now let’s go into which appliances consume the most electricity in a typical household. Although a few of these appliances have a lower wattage than some of the appliances listed above, they are generally used for a longer period of time, over more days of the year, so their energy usage is higher. This appliance electricity usage comparison will show both the approximate wattage of the appliance and the estimated amount of energy that is consumed each month, in kWh.
- Central Air Conditioner (3,250-3,800 watts) – 1,450 kWh/month
- Water Heater (4,500-5,500 watts) – 310 kWh/month
- Refrigerator (1,200-1,400 watts) – 205 kWh/month
- to estimate the number of hours a refrigerator is running at maximum wattage, you should divide the total time it is running by 3
- although they are running constantly, refrigerators cycle ‘on and off’ in order to maintain the interior temperature
- Dryer (1,800-5,000 watts) – 75 kWh/month
- Oven Range (1,200 watts) – 58 kWh/month
- Lighting (various wattage) – 50 kWh/month
- Dishwasher (1,200-2,400 watts) – 30 kWh/month
- the drying feature increases energy consumption greatly
- Television (150-200 watts) – 27 kWh/month
- Microwave (750-1,100 watts) – 16 kWh/month
- Washing Machine (500-800 watts) – 9 kWh/month
Do unused appliances use electricity?
Yes! Many appliances will continue to take in a small amount of electricity even after they have been switched off, known as ‘stand-by’ power or ‘phantom loads’. This is especially true of appliances such as computers, televisions, and kitchen appliances and it will increase an appliance’s electricity usage by a few watt-hours. Although this doesn’t seem like very much, this energy usage adds up and you will end up paying more for the electricity you weren’t even really using.
Should I unplug appliances when not in use?
It is beneficial to unplug appliances when they aren’t in use to avoid these ‘phantom loads’. Even a device charger will take in power whether or not a device is even connected, especially if it has a transformer.
Using a power strip can take away the bother of needing to actually unplug an appliance as you can simply turn off appliances using the specific switch on the power strip. Or, if you don’t think you’ll remember to unplug appliances, you can get a timer plug-in socket to turn off an appliance at a certain time of the day.
Does it save money to unplug appliances?
Unplugging appliances and devices will save you money on your electricity bills as you can avoid electricity being used unnecessarily and you can estimate your monthly electricity bill more accurately.
How much does it cost to have a light bulb on?
The cost of running a light bulb per hour is relatively low no matter what type of light bulb being used, but an incandescent bulb will cost more than an LED as the equivalent wattage is much lower. Below you’ll find some average costs as a guide.
100-watt light bulb
A 100-watt incandescent light bulb is the equivalent to a 27-watt LED bulb. This wattage consumes 0.027 kWh per hour and the 100-watt light bulb cost per hour is less than $0.01.
60-watt light bulb
A 60-watt incandescent light bulb is the equivalent to a 15-watt LED bulb. This wattage consumes 0.014 kWh per hour and the 60-watt light bulb cost per hour is less than $0.01.
40-watt light bulb
A 40-watt incandescent light bulb is the equivalent to an 11-watt LED bulb. This wattage consumes 0.01 kWh per hour and the 40-watt light bulb cost per hour is less than $0.01.
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How long can you leave a light bulb on?
The length of time that a light bulb can be left on depends on the type of light bulb being used:
- LEDs have a lifespan of 35,000 to 50,000 hours and can be left on 24/7.
- Incandescent bulbs have a lifespan of only 750 to 2,000 hours and should be turned off whenever they aren’t needed.
- Fluorescent bulbs have a lifespan of 24,000-36,000 hours and should only be turned off if you are leaving a room for longer than 15 minutes. This is because they are not built to be frequently turned on and off.
- Halogen bulbs have a lifespan of 2,000 to 4,000 hours and should also be turned off whenever they aren’t needed.
- CFL bulbs have a lifespan of 35,000 to 50,000 hours and should be treated in the same way as fluorescent bulbs.
The reason that LED lights can be left on for such a long time is that they produce a very minimal amount of heat when they are running. This means that they are very unlikely to overheat or start a fire, which can happen with more traditional bulbs.
Conventional bulbs, i.e. incandescent bulbs, produce only 10% of light energy, the remaining 90% comes out as heat energy, and their heat only intensifies the longer they are left on increasing the chances of fire. This is why it is very important that they are turned off whenever they are not in use. An LED light, on the other hand, will simply dim if it becomes overheated so they are the perfect solution if you need a bulb to be running for an extended amount of time.
Are LED bulbs cheaper to run?
LED bulbs are much cheaper to run than conventional bulbs as they are hugely efficient in comparison. There is a large difference in wattage, e.g. a 20W LED is equivalent to a 75W incandescent bulb, and LED bulbs will stay relatively cool, and therefore safe, with 90% of energy being converted to light and only 10% converted to heat energy. High-quality LEDs even contain heat sinks that actively take excess heat away from the bulb itself. Typically, an LED bulb uses 90% less electricity than conventional bulbs and so it will be that much cheaper to run.
Yes, LEDs are more expensive to buy than a conventional bulb, but they last up to 5 times longer and consume much less energy, so they are well worth the investment.
Being smart with your household appliances, by switching to more energy-efficient models or unplugging them when they are not being used, can help you to cut down on your energy consumption and therefore your energy bills.
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