Ask the Expert: Energy use of home office equipment
If I leave my computer and printer on overnight - how much energy do they use? Is it cost effective to turn them off every night?
Asked by: Jimmee B., West Melbourne, FL
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A. Jimmee, the answer to your question is yes, shutting a device down when not in use is the best way to save energy. Letting it sleep instead will increase overall electricity consumption and cost more, but only a few cents annually (less than a dollar per year per device).
Top energy consumers in your home office
Desktop computers tend to consume the most energy, so they have the largest potential for energy savings, followed by laptops, tablets, and smart phones. Overall, these kinds of devices tend to consume a relatively small amount of energy annually, and (particularly for laptops) sleep modes have improved enough that there’s a relatively small difference between putting a computer to sleep and turning it off entirely. However, it’s still generally a good idea to turn off and unplug any electronic devices to eliminate phantom loads (when a device appears to be off, but still draws power).
For reference, here are some estimates of annual electricity associated cost and consumption for typical home office devices based on our residential customer price of $0.10/kWh:
- Desktop –$27.50 / 275 kWh
- Laptop –$5.30 / 53 kWh
- Monitor –$4.10/41 kWh
- Printer –$1.10 / 11 kWh
- Tablet (average, with two charging cables) – $0.61 / 6.1 kWh
- Smartphone (average, with 2 chargers) –$0.45 / 4.5 kWh
As far as what types of savings to expect from turning off your equipment, it varies. Here are some guidelines:
Computers & printers
For a desktop computer that is currently always on, you could save an average of $15/year by turning it off for 8 hours each night. However, if you prefer to enable your computer’s sleep mode, the difference in savings is only about $.44/year compared to turning it off, with saving of about $14.56/year.
For a laptop computer that is currently always on, potential annual savings would be around $4.60/year when you turn it off for 8 hours each day and about $4.10/year if you prefer to let it go to sleep mode.
A typical inkjet printer is estimated to spend about half of its time in standby mode. If you eliminate the associated energy consumption by turning off the printer, you would likely save around $0.50 per year.
In general, we’d recommend turning off your computer whenever possible to maximize energy savings. However, automatically putting your computer to sleep whenever possible is a good backup plan that will save nearly as much energy as turning it off entirely. In fact, some sources suggest that enabling the sleep mode settings is actually a better approach in some ways since it doesn’t require you to remember to turn off your computer.
ENERGY STAR® program’s Office Equipment Calculator allows you to input an electricity cost and then directly see how much energy an ENERGY STAR®-qualified device uses relative to a standard model. Since the ENERGY STAR® calculator can be used to estimate energy consumption for non-efficient (baseline) devices; it’s helpful in addressing many questions related to electronics and home office equipment.