The one plug-in device experts say you should never leave on standby at night if you want to stop “phantom” energy loss

It’s the last glow in the corner of the room when everything else looks off. The TV’s gone dark, the laptop’s shut, but a tiny red eye is still lit on the skirting board. A warm brick of plastic humming quietly to itself while you sleep. Most of us ignore it. Energy auditors don’t. Ask them which plug‑in device you should never leave on at night if you want to stop “phantom” energy loss, and the answer is surprisingly consistent: your plug‑in electric heater.

It was in a semi in Wolverhampton, during a winter home energy visit, that I first saw the numbers bite. The advisor plugged a heater into a monitor, clicked it “off” with the little rocker switch, and watched the display barely flinch. The element was cold, but the standby circuitry was still sipping power. Multiply that by every night of the heating season and you don’t just get wasted watts; you get a line on your bill you never meant to sign.

What “phantom” energy really is

“Phantom” or “vampire” energy is the electricity devices draw when you think they’ve stopped. Anything with a light, a remote sensor, a digital display or a warm plug is still connected to the grid’s drip feed, ticking away in the background. It’s quiet, invisible, and, over time, surprisingly expensive.

Individually, some gadgets only pull a trickle – a router here, a phone charger there. But high‑wattage plug‑in heaters sit in a different league. Even in standby, their control boards and safety sensors can use more than smaller electronics do when they’re actually on. The brutal truth: the kit you bought to keep you warm can keep draining your wallet long after you’ve gone to bed.

From an electrical point of view, anything that converts a lot of power to heat is designed for short, deliberate bursts of use, not casual idling. When you leave a heater plugged in at the wall 24/7, you’re essentially parking a sports car with the engine still ticking over. It doesn’t roar, but it burns.

Why plug‑in heaters are the one device you should never leave on standby at night

Ask a home energy assessor what they unplug first in a wasteful room and they’ll walk straight past the fairy lights and the telly. They go for the plug‑in heater. There are three blunt reasons: wattage, run time and risk.

A typical portable heater runs at 1,500–2,000 watts when it’s on full. Manufacturers have improved thermostats and safety cut‑outs, but many models still draw power on standby to keep controls “ready”. Leave that plugged in and “off” in a bedroom all winter and you’re not only wasting energy; you’re gambling on a device that was never designed to be forgotten.

Most of us don’t treat heaters like kettles, either. We plug them in “for a bit”, then tuck them behind a chair, next to a curtain, or under a desk. Years later, the cable is kinked, the plug is tired and the socket is slightly discoloured. The standby draw is small, but the combination of heat history and constant live connection is exactly what fire officers wince at.

“If there’s one thing I ask people to fully switch off at the wall before bed, it’s portable heaters,” one inspector told me. “They’re high power, often old, and far too easy to forget.”

The small habit that stops a slow leak

The fix isn’t glamorous. It’s a hand on a switch. But once you’ve seen the figures on an energy monitor, it’s hard to walk away from a glowing rocker without flicking it.

Before you go to bed, do a quiet lap of the rooms you actually heat. Unplug or switch off at the wall any portable heaters, heated airers, plug‑in radiators, and heated blankets you’re not actively using. Don’t just click the little control on the device itself; kill the power at the socket. It’s a three‑second ritual that removes the phantom draw completely.

People often resist the idea because plugging and unplugging feels like fuss. The trick is to design out the faff. Use switched extension leads you can reach easily. Keep heaters on their own strip, labelled, not squeezed in behind the telly. Once the motion is simple – one row of switches on, one row off – the habit stops feeling like effort and starts feeling like control.

Other energy gluttons worth taming

Heaters are the headline act, but they’re not the only culprits. The same late‑night sweep can quietly defuse several mini vampires:

• Old TV and set‑top box combos with bright standby lights.
• Games consoles left in “rest” mode for automatic updates.
• Heated airers and dehumidifiers with glowing clocks.
• Plug‑in chargers with no device attached.

You don’t need to live in the dark or unplug the fridge. Focus on the obvious high‑power add‑ons and the older boxes with lights and fans. If you can hear or see them when they’re “off”, they’re still on.

How to spot phantom drain in your own home

Once you know what to look and feel for, phantom energy starts to show itself. There’s a simple, almost old‑fashioned checklist that energy teams still use on visits.

First, look for lights: red standby dots, little blue glows, digital clocks. Anything lit is taking a slice of power. Next, feel for warmth at the plug or adaptor after the device has supposedly been off for a while. A slightly warm plug on a heater, airer or TV unit is a clue that something is still flowing.

If you want hard numbers, a plug‑in energy monitor costs less than a takeaway and will show you draw in real time. Plug the suspect device into the meter, turn it off on its own switch, and see what’s left. Even 3–5 watts, 24 hours a day, adds up over a year. On a big heater or old dehumidifier, it’s often more than that.

Give yourself a “two‑second test”: light, warmth, switch. If you can see a light, feel warmth or flick a switch, you can probably cut a phantom leak.

Simple tools that make it easier

You don’t need a smart home overhaul to tame standby, just a few practical helpers:

• Switched power strips for clusters of devices.
• A basic plug‑in energy monitor to identify the worst offenders.
• Timers for things that never need to run all night, like heated airers.

Place the switches somewhere you can reach without moving furniture. Make it as easy to turn things off as it is to leave them on.

A tiny change with a quiet payoff

Unplugging a heater at the wall won’t halve your bill in a week, but it changes the baseline of your home. You stop paying for comfort you’re not getting – heat from an element that isn’t even glowing, power to a circuit that’s just waiting. It’s less about hair‑shirt frugality and more about design that respects what you actually use.

Households that adopt a simple “last circuit” routine – sockets, windows, doors – often report something more than savings. They sleep better, because the house feels genuinely off. Everything that should be cold is cold. The devices that should be silent are silent. And the heaters are exactly where they ought to be at night: unplugged, unbothered, and no longer drinking in the dark.

Key point	Detail	Why it matters
Unplug heaters at night	Switch off at the wall, not just on the unit	Stops phantom draw from high‑wattage devices and cuts risk
Hunt for “lit but off” kit	Lights, warm plugs, humming fans after “off”	Simple way to uncover hidden standby drains
Use helpers, not heroics	Switched strips, timers, energy monitors	Makes good habits easy enough to keep doing

FAQ:

• Is standby on a heater really that bad? On its own, standby might only draw tens of watts, but because heaters are high‑power devices used for months at a time, their wasted energy stacks up quickly compared with smaller gadgets.
  
• Do I need to unplug every appliance at night? No. Focus on portable heaters, heated airers, old TVs, consoles and anything warm or lit when “off”. Essential appliances like fridges should stay on.
  
• Will smart plugs help? Yes, if you actually use them. Smart plugs let you cut power on a schedule or from your phone, which is handy for hard‑to‑reach heaters and older electronics.
  
• Is this just about money, or safety too? Both. Cutting power at the socket reduces fire risk from tired plugs and cables on high‑load devices, especially older plug‑in heaters.
  
• How much can I save by tackling phantom energy? It varies by home, but audits suggest that trimming standby on big offenders can shave a noticeable chunk off annual bills, especially in homes full of plug‑in heaters and older electronics.