Halloween is approaching, bringing a night of ghosts and ghouls – or at least bored teenagers bearing shaving-cream. The phantoms on your doorstep may not be real, but indoors you are likely to encounter vampires – appliances that suck energy around the clock.

A device that draws power when turned off seems counter-intuitive. Such a feat was impossible in the era of mechanical appliances. But now we’re surrounded by a new generation of devices – with digital displays, electronic controls and remote starts – that are always in standby mode.

Ironically, now some home electronics use more power when they are off than when they are on.

Vampire power loads are the electrical equivalent of vehicular idling; they waste energy and aggravate climate change for no practical purpose. Electricity generation accounts for more than a third of the nation’s carbon dioxide emissions. The wasted electricity from phantom appliances nationwide represents the output of roughly 50 large power plants.

Powering machines that are ostensibly off is not only environmentally damaging, it is expensive. For individual households, this hidden waste can leach $150 to $400 each year.

The easiest means to stem this electricity drain would be to establish energy-efficiency standards requiring manufacturers to minimize the idle power load of their appliances. Sadly, that kind of forward-thinking legislation seems unlikely to emerge from Congress or the White House anytime soon.

The next best step would be to enact labeling laws that help consumers identify devices with high phantom loads. That too will likely have to wait. (The current administration is too busy working to gut or privatize the popular federal Energy Star program that helps consumers identify energy-efficient appliances.)

So for now homeowners are left to face down energy vampires on their own. It’s no small challenge; a typical American household has upwards of 30 always-on appliances.

You can rout out phantom devices with a quick visual inventory (looking for green-dot lights, electronic displays and anything with a remote). Past studies have identified some of the most voracious vampires:

Big users (30 kWh or more) include laptops, televisions, satellite TV or cable boxes, boom boxes, home copiers, fax machines, printers and doorbells.

Moderate users (10-30 kWh) include microwave ovens, garage door openers, routers, desktop computers, and DVD and CD players.

If you want to calculate just how much energy each appliance wastes in the “off” mode, borrow a Kill-a-Watt meter from your local library. Once you’ve gathered data for each appliance, you can calculate its daily and annual energy consumption.

Some vampire appliances can be put on a diet. To limit the phantom draw of entertainment devices, consider disabling their “quick start” or “instant on” functions. Set computers to enter “sleep” mode after 10 minutes of inactivity.

The only way to completely prevent vampire power loss, though, is to unplug electronic appliances. Devices such as boom boxes or coffee makers can be unplugged at the outlet when not in use. Where there is a cluster of related appliances involving a computer or entertainment center, you can control them most easily and economically by plugging all the cords into a single power strip and turning that off.

Acquiring the double-shutdown habit is easier if you can locate power strips in readily accessible locations. But if that is not feasible, try to find the upsides to stretching. My sub-desk scrambles for the power strip – twice daily – help counteract hours of sitting and alert me to when office dust bunnies are morphing into dust buffalo.

Beyond traditional power strips, there are more sophisticated options for those who prefer automated shutdowns. Advanced power strips can be programmed to turn off multiple devices on a timer or when one master device – like a computer or television – is shut down. For an illustration of advanced power strip options, see https://www.nrel.gov/docs/fy14osti/60461.pdf.

The double shutdown that power strips require is neither efficient nor convenient. It’s a temporary fix to a problem that appliance manufacturers have created and need to solve. In developing a generation of always-on devices, they increased electricity demand unnecessarily, driving up consumers’ long-term costs and aggravating greenhouse gas pollution.

What we need now is more responsible design of appliances, ridding our home of energy vampires. That trick would be a treat we’d enjoy year-round.

Marina Schauffler provides research, writing, and editing services to nonprofit and social enterprise organizations through Natural Choices (naturalchoices.com).