Appliance Energy Usage: An Overview
From washers and dryers to home entertainment to the devices we use for cooking and cleaning, our household appliances are an indispensable part of daily life. However, these modern conveniences come at a cost - both to our wallets and to the environment.
Home appliances, not counting air-conditioning units, are responsible for about 28% of a typical U.S. household's total energy bill, with heating, cooling, lighting, and water heating comprising the rest. In total, that adds up to 386 billion kilowatt-hours of residential power usage per year in the United States and emitting 264 million tons of CO2.
While major appliances such as dishwashers and clothes dryers can use a lot of power for short durations, the power consumed by small items like phone chargers, computers, and coffee makers can add up as well - often when they're not being used. However, choosing energy-efficient appliances and using our appliances wisely can both reduce our carbon footprint and our electric bills.
Power use of household items
40 Gal. Water Heater
Calculating Your Energy Usage
Figuring out how much power your appliances and devices use can seem daunting, but it can easily be determined with a bit of research and some simple math. Most appliances sold in the United States will have their energy use, or wattage, stamped on the back, bottom, or inside the door.
Since power utilities measure energy use in kilowatt-hours (kWh), we can multiply the wattage of an appliance by the estimated number of hours it is used per month to calculate the monthly watt-hours. Dividing by 1,000, we then arrive at the number of kilowatt-hours for an appliance.
As an example, we will use a clothes washer using 400 watts of power that (for simplicity's sake), has wash cycles of exactly an hour. If we do eight loads of laundry per week, that adds up to 3,200 watts used. In a month, that's 12,800 watt-hours or 12.8 kWh. With an average energy cost of nearly $.13 per kilowatt-hour (as of February 2012), that's $1.66 spent on washing clothes.
Washing machines are relatively light consumers of power. Dryers, on the other hand, are energy hogs. A 4,500-watt dryer that dries the laundry loads above in one-hour cycles will use 36 kilowatts of power weekly, 144 kWh monthly, and cost $18.72 per month.
Fortunately, most household appliances are not in constant usage, but are only used for short periods at a time. However, our appliances are often still consuming power even when we're not using them.
Phantom Load: The Ghost in Your Machines
Standby power, also known by the far more creative names phantom load and vampire power, is the power drawn by an electronic device or appliance when not in use. From the LED on a toaster to a plugged-in phone charger to the blinking 12:00 on the DVD player, these devices are always on, even when they're turned off.
Some appliances can use more power in standby mode than in actual use. A typical 1,400 watt microwave, for example, draws about three watts per hour - that's 72 watts over a day. Running the microwave for three minutes at full power, on the other hand, uses 70 watts.
Among the worst offenders are cable and satellite TV set-top boxes - particularly those with on-demand and video recording abilities. On average, these draw 30 or more watts per hour in "off mode," even when they're not recording. That adds up to more than 260 kilowatt-hours per year.
Though it may seem frightening to the energy-conscious consumer, busting the phantom load ghost is possible with a few simple power-conservation measures. Unplugging kitchen appliances that are not in use can save lots of power in the long term. A power strip with an off switch can also help keep multiple devices from wasting energy when they're not being used.
Unplugging laptop and mobile phone chargers once devices are charged can also help. Some mobile phone chargers use as much as a watt of power when they're not connected to the phone, and waste up to four times that to continue charging a phone that has already been fully charged.
Finally, there are several electricity meters available to consumers that can help them pinpoint where their power dollars are going. Serving as a bridge between the wall outlet and the appliance to be monitored, these electricity meters measure the amount of power an appliance consumes when on or off, empowering consumers to use energy more wisely and significantly cut their electric bills.
Sources and Further Information
- How is electricity used in U.S. homes? - FAQ - U.S. Energy Information Administration (EIA)
Energy Information Administration - EIA - Official Energy Statistics from the U.S. Government
- Where Does My Money Go? : ENERGY STAR
Average annual energy bill by category of use.
- Energy Savers: Estimating Appliance and Home Electronic Energy Use
If you're trying to decide whether to invest in a more energy-efficient appliance or you'd like to determine your electricity loads, you may want to estimate appliance energy consumption.
- Frequently Asked Questions About My Carbon Footprint
Your personal carbon footprint is the sum of the information you input into the calculator, resulting in an estimate of the carbon dioxide that is produced by home energy use, transportation, and household waste.
- Standby Power : Data
We measured the standby power of many, many, products. The table below summarizes those measurements, with the average, minimum, and maximum power levels observed while in standby.