Do Chargers Left Plugged In Waste Electricity?
Maya Lindqvist, Everyday science writer (AI-assisted) · · updated
Yes, chargers left plugged in can waste electricity, even when they aren't charging a device. This phenomenon is often referred to as "phantom load" or "vampire power."
You may have noticed that your phone charger gets warm even when your phone isn't connected. Older adapters that are large and warm to the touch use several watts, while newer lightweight ones that stay cool draw less than one watt [2]. A charger that is noticeably warm with nothing attached is drawing more than a modern one should, and is worth replacing.
What Happens with Chargers?
Chargers work by converting the alternating current (AC) from your wall outlet into a direct current (DC) suitable for charging your devices. However, many chargers continue to draw power from the outlet even when not in use.
Think of it like a water hose left running. If you have a hose turned on, water flows freely. But even if you stop using it temporarily, if the hose is still connected to the tap, water continues to trickle out. Similarly, chargers can still draw power from your outlet even when they aren't actively charging a device.
Here's how it breaks down:
- Charger Idle State: When you unplug your device, the charger often remains plugged in. In this state, it can continue to use electricity—typically a small amount, but it adds up over time.
- Power Consumption: Most modern chargers, like most standby loads, draw less than 0.5 watts when idle [1]. For instance, a charger drawing 0.5 watts for a 730-hour month uses about 0.37 kWh, roughly 0.11 at an example price of 0.30 per kWh; over a year that is about 4.4 kWh.
- Cumulative Effect: With multiple chargers in a household—like those for phones, tablets, and laptops—the cumulative effect can be significant. If you have five chargers that each waste about 0.3 watts, that totals 1.5 watts. Over a month (730 hours) that is about 1.1 kWh, or about 0.33 in electricity (assuming an example price of 0.30 per kWh in your currency).
The Impact at Home
You might wonder, what does this mean for your daily life? The impact is twofold: financial and environmental.
- Financial Impact: If you have several chargers plugged in all the time, you could be throwing away money—imagine it like losing a few cents a week. At under 0.5 watts, a charger left plugged in uses at most about 0.37 kilowatt-hours (kWh) a month. To put that in perspective, if you have three chargers plugged in continuously, that's at most about 1.1 kWh a month, around $0.14 to $0.55 on your electric bill at $0.13 to $0.50 per kWh.
- Environmental Impact: Wasting electricity also contributes to higher carbon emissions, depending on how your electricity is generated. For instance, if your electricity comes from fossil fuels, every kilowatt-hour wasted contributes to more carbon dioxide in the atmosphere. Reducing unnecessary energy consumption not only saves you money but also helps lessen your carbon footprint. Unplugging chargers alone saves little; the bigger prize is standby power across all your devices, which together amounts to 5-10% of residential electricity use [1].
What Can You Do?
Here are some practical steps you can take to minimize wasted electricity from chargers:
- Unplug When Not in Use: Make it a habit to unplug chargers after you’ve finished charging your devices. This simple action can save you a noticeable amount of energy over time, especially if you charge devices frequently.
- Use Power Strips: Consider using a power strip with an on/off switch. This allows you to easily cut power to multiple chargers at once. Imagine you have five chargers plugged in; instead of unplugging each one, you can simply flip a switch to stop the flow of electricity, which can be particularly useful during extended periods away from home.
- Smart Plugs: You can invest in smart plugs that can be programmed to turn off at specific times or controlled remotely. For example, you might set a smart plug to power off your phone charger at midnight and turn back on at 7 a.m. This ensures that your charger isn’t drawing power during the night when it’s not needed. Bear in mind that a smart plug draws standby power of its own, so on a single charger it may cost more than it saves.
- Charge Wisely: Only charge devices when necessary, and avoid leaving them plugged in overnight unless your device requires it. Think about it like watering a plant: overwatering can harm the plant just as leaving your device plugged in too long can waste electricity.
Conclusion
Chargers left plugged in do waste electricity, leading to unnecessary costs and environmental impacts. By adopting simple habits like unplugging chargers when they're not in use, you can save money and contribute to energy conservation.
It’s a small change, but it can make a significant difference over time.
Questions readers ask
How much energy do chargers waste when left plugged in?
Chargers typically waste less than 0.5 watts when idle [1]. A device drawing 1 watt constantly for a year uses about 9 kWh [3]. So a 0.5-watt charger uses about 4.4 kWh a year, roughly 1.31 at an example price of 0.30 per kWh.
Are all chargers the same in terms of energy waste?
Not all chargers waste the same amount of energy. Older models tend to consume more power when idle compared to newer, more energy-efficient chargers: large, warm adapters use several watts, lightweight cool ones less than one [2].
What are some signs that my charger is using too much power?
If your charger feels warm to the touch when it's not charging a device, it may be consuming more energy than necessary. Consider unplugging it when not in use.
*Corrected 2026-11-01: Figures recomputed from the stated watts: five 0.3 W chargers are 1.5 W, about 1.1 kWh and 0.33 a month, not 3.6 W and 2.16; a charger wastes at most about 0.37 kWh a month; the unsupported 30% smart-plug saving was removed; sources added.*