The Electricity Your Home Uses While Nobody’s Using Anything

At 3 a.m., with everyone asleep and every screen dark, your house is still drawing power. The question is how much.

In 2015, the Natural Resources Defense Council, working with Home Energy Analytics and Stanford’s Sustainable Systems Lab, published a report called Home Idle Load. It drew on hourly smart meter data from about 70,000 northern California homes, a second set of 2,750 Bay Area homes, and detailed in-person audits of 10 houses.

The headline finding: “always-on” use by devices that weren’t actively doing anything averaged nearly 23 percent of household electricity in those northern California homes. That includes things in standby, things in sleep mode ready to wake up fast, and things simply left on with nobody around.

What does that cost? At the 2015 national average electricity rate NRDC used, it worked out to about $165 a household per year, or roughly $1 a year for every watt that never turns off. NRDC scaled that up to about $19 billion nationally.

Why so much? One reason, the report says, is that appliances went digital. Washers, dryers and fridges that used to be purely mechanical now have displays, electronic controls and, increasingly, internet connections.

The audits made it concrete. The 10 homes averaged 65 electrical devices each, and 43 of them drew at least 1 watt while the house was idle. Across all 10 homes, 350 small devices each drawing 12 watts or less added up to 43 percent of the total idle load. Two more examples from the report’s tips:

• A TV “quick start” setting can use as much as 37 watts around the clock in some models.
• Old second fridges in garages and basements can cost residents more than $100 a year.

Two limits. The data came from northern California, and NRDC notes the share may be lower in regions that use more electricity overall. And both prices and devices have changed since 2015.