Energy Audit: Another Reason to Hate Cable TV

I recently compared electric bills with my brother and was rather surprised to discover that my bill was noticeably higher than his. We live in the same general area and have similarly sized but differently laid-out living spaces. Weather has been moderate and neither of us used any air conditioning or heating during the billing period. We're also both single and have mostly similar stuff in our homes, with the exception of some IT equipment that is necessary for my work. It didn't seem like that equipment --most of which is not used on a full-time basis --could be the difference.

To figure out what's going on, I started an audit, using a nifty device called the Kill-A-Watt (KAW) that cost under $30. The audit is still incomplete because the KAW can only be used on one device at a time and ideally should be left plugged in to the device for several hours or days in order to get a good reading of average power use over time. Generally speaking, the more intermittent the use, the more time should elapse during measurement. For something like a refrigerator that cycles on and off regularly during the day, 24 hours should be adequate. For a television set on which use varies from day to day depending on what's on, you might want to measure for longer, maybe a full week. Some devices are in consistent use and an hour or two of measurement will suffice.

I started the process knowing that many devices these days don't really turn "off" completely, rather they go into a suspended state (usually called "standby") in which they continue to consume small amounts of power, sometimes doing some background tasks like getting updates from the internet and performing system maintenance, or at times just using the minimal amount of power necessary to receive and process the "on" signal from a remote control. This electricity use, known as "parasitic load" or "vampire load" can vary widely across different products. Part of the goal of this audit is to quantify the full extent of this parasitic load in my home.