With the intent of decreasing our home’s electricity usage, I measured the electrical usage of many of the appliances, toys, gadgets, etc. in the house using a device called a Kill-A-Watt. It’s an inexpensive device that goes between your device and the wall outlet. Among other features, it can tell you how many watts a device is drawing at the moment or how many kilowatt-hours it has used over time.
In the tables below, I am using 11 cents per kilowatt hour for computinpg the costs, since that’s about what power costs here. Note: I can only measure devices that plug into a 110V socket, so the air conditioner and dryer can’t be measured.
I divided the devices in my house into three basic categories based on how they are used. The first category is devices that run in batches or cycles. Here’s a table showing how much power each cycle consumes. Note: these figures only measure the electricity used by the device itself, not in heating the water, etc.
The second category is devices that run all the time, including appliances like the fridge. I’ve also included the devices in the home that draw power even when off. For instance, notice that the TV draws 2 watts when it’s “off”, since it’s still doing things like listening for the remote control.
The final table shows items that are measured by the hour. Even the most power-hungry devices don’t cost much per hour, so I included a column to show you how many hours $1 of electricity will buy you.
To sum up, here were the main things that I found surprising or insightful:
- For CRT monitors, displayed a white screen takes far more power than a black screen
- If you’re cold at night, use an electric blanket, not a space heater!
- The DVR never really shuts off.
- Spinning down the hard drive in the desktop computer isn’t a huge power savings, but standy is.
- The desktop computer only uses marginally more power when very busy compared to at idle.
I’ve got a few more things to measure, but if you have any requests, let me know. Also, if I know you, you’re free to borrow my kill-a-watt to measure stuff around your place.