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Can you charge a laptop for less?
Worries about skyrocketing energy prices are forcing us all to examine how much energy we use.
If laptops are among the most-used items in your home and frequently need charging, you might be wondering about whether there's a cost saving to be made by how you charge yours.
We decided to find out, by investigating the cost of charging a laptop when you need it versus keeping it plugged in all the time.
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Charging a laptop differently, what's the price difference?
We took four different laptops of different ages and measured the kilowatt hours of energy used during a 24-hour period for three popular charging scenarios:
Plugged in We left each laptop plugged in for a full 24-hour period
Charging when you need it (20% to 100%) Over an eight-hour working day we put each laptop onto charge every time it got down to 20% battery remaining. We left it on charge and then unplugged the charger every time each laptop reached 100% fully charged. After the eight hours we unplugged the charger for a further 16 hours, then took our measurements.
Charging when you need it (30% to 80%) Over an eight-hour working day we put each laptop onto charge every time it got down to 30% battery remaining. We left it on charge and then unplugged the charger every time each laptop reached 80% fully charged. After the eight hours we unplugged the charger for a further 16 hours, then took our measurements.
Here's what we found:
| Method of charging | Average yearly cost | Yearly savings by switching from 'Plugged in' to this method |
|---|---|---|
| Plugged in | £6.83 | n/a |
| Charging when you need it (20% to 100%) | £6.70 | £0.13 |
| Charging when you need it (30% to 80%) | £6.03 | £0.80 |
| Table notes: average laptop age 2.5 years, average laptop battery capacity 48.1Wh, average yearly cost - assumed a laptop is used five days a week, representing a typical working week, electricity unit price 30p/kWh | ||
It turns out that charging a laptop isn't one of the big energy guzzlers. Although leaving your laptop plugged in all day uses a little more energy than just charging when you need it, the yearly savings aren't huge.
The most our snapshot test showed was an average saving of 80p a year if you charge your laptop when you need it.
But if you have multiple laptops in your home, or feel charging your laptop in the cheapest way possible is a habit you can change, there are savings to be made.
The biggest ways you can save money on energy
Given that changing the way you charge your laptop isn't going to make a significant saving as energy bills rise, we asked Emily Seymour, Which? sustainability editor, what changes would make a difference around the home.
Emily said: 'For most households the biggest energy guzzlers through the winter are central heating and appliances such as tumble dryers.'
Her advice on the best place to focus your energy saving? 'Making sure your home is as insulated and draught-proofed as possible, so that the heat you generate stays inside.
'Many households could also make savings while staying warm by lowering their boiler's flow temperature,' Emily says.
And if you find you're unable to pay your energy bills this winter? 'Contact your energy provider,' Emily says. 'It's obliged to help you with a payment plan you can afford, and may be able to grant you access to hardship funds or other financial support.'
Ten ways to reduce your energy bills
How can you make your laptop more efficient?
While it's good news that laptops aren't exceedingly energy hungry, there are behaviours you can change to make yours more efficient and save you money in the long run, according to Lisa Barber, Which? Computing editor.
Lisa says: 'Don't leave your laptop on standby, even though this isn't going to rack up your energy bills, as this reduces the lifespan of your battery. Instead, regularly shut it down completely.
'Also, get in the habit of checking your charger, as a broken or damaged one can harm your laptop. Look out for the cable fraying. It's far cheaper to buy a new charger than a new laptop.'
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How we measured energy use and how you can too
Your laptop might give slightly different energy-use figures, depending on factors such as age, battery size and efficiency of internal components.
We plugged laptop chargers into an energy (power) meter, which measures the total kilowatt hours used in our calculations.
We used the RS Pro energy meter, £28, from RS Components. If you're interested in measuring the energy use of your laptop or other appliances around your home, you can buy similar meters starting from around £18 from popular retailers such as Amazon and Screwfix.
If you have one, you can also use your smart meter to track your devices' energy use in real time.
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