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Cutting carbon

How to measure the carbon impact of working from home

Alex B's desk working from home

Lots more of us have been working from home recently, which means we’ve brought business-related carbon emissions home with us. As a B Corp, we’re committed to understanding our carbon impact, and we want to help other companies do the same.

Around 15 million people have been working from home since coronavirus restrictions came into place earlier this year. Companies might have seen direct emissions in the workplace fall, but these emissions haven’t disappeared. They’re just being created somewhere else. If businesses don’t understand how to measure these emissions, millions of tonnes of CO2 might not be measured or reported. So we contributed to a paper that gives businesses clear guidance on measuring the carbon impact of a remote workforce.

Companies can measure the impact of heating and electricity being used to work from home

Environmental consultants EcoAct have written a whitepaper on homeworking emissions to help businesses measure their carbon impact more accurately. We contributed to this work, and we thought an overview of the key guidance might be useful. Fair warning, there’s a bit of maths involved. 

1. Electricity

If you’re working from home, you’ll be using more electricity than normal. You might be charging equipment like laptops and phones, and you’ll likely have your lights on more. And more electricity can mean more emissions. 

EcoAct estimates that average power use for a laptop or computer is 140 watts. For lighting, it’s 10 watts. To work out the total amount of electricity used by your team, you need to multiply this by the number of employees working from home, and the number of working hours in a month.

Once you’ve worked out how many kWh (kilowatt hours) your team has used, you’ll need to multiply it by the emissions factor for electricity, which is 0.256 kg of CO2e per kWh. That figure’s based on an average home which hasn’t switched to a renewable supplier like Bulb.

Let’s look at an example for Company A, which has 1,500 employees, each working a 40 hour week. You can change the number of working hours to suit your business.

  • Laptops: 140 watts X 1,500 people X 160 working hours each month = 33,600 kWh electricity

  • Lighting: 10 watts X 1,500 people X 160 working hours each month = 2,400 kWh electricity

  • Together, that’s 36,000 kWh of electricity each month for all employees working from home.

  • 36,000 kWh X 0.256 kg of CO2 = 9,216 kg of CO2.

Illustration of laptops and lights working from home
Working from home means charging laptops and using lights more than usual, which can cause emissions

2. Heating

Working from home means employees are likely to need more heating, too. 85% of homes in the UK use natural gas for heating, so when the cold weather creeps in, our CO2 emissions creep up.

EcoAct estimates that it takes 5kWh gas to heat your home for an hour. This works out at an extra 800 kWh to keep each employee warm a month, once we take into account that the heating is only on between October - March, and not for 24 hours a day. 

Data shows that around one third of employees said there would be someone at home during the day, even before coronavirus. So to work out the energy used to heat homes only caused by remote working (i.e. that wouldn’t have happened normally), multiply the number of employees working from home by 66.7%. That number multiplied by 800 kWh gives the amount of heating used by all employees each month. 

Multiply your total by the emissions factor for natural gas, which is 0.184 kg of CO2 per kWh, and voila! There’s your impact.

Let’s look at an example for Company B, with 70 employees, each working a 45 hour week.

  • 800 kWh X ( 66.7% X 70 people ) = 37,352 kWh more heating each month for all employees

  • 37,352 kWh X 0.184 kg of CO2 = 6,872 kg of CO2.

Illustration of heating impact of working from home
85% of UK homes use gas for heating. So when the cold weather creeps in, our CO2 creeps up

3. Cooling

The paper looks at similar calculations for home cooling. This isn’t as relevant for the UK, because very few homes have air conditioning. The carbon impact of cooling is considerable in other parts of the world - so it’s worth bearing this in mind if your business has any international remote workers. 

Get your team involved to make measurements more accurate 

The paper assumes that most companies won’t know a huge amount about their employees’ home environment, like how many people they live with, or which energy supplier they’re with. But to make the data more accurate, you can always send surveys to your team to find out.  For example, you can send out a survey to check how many employees are with a 100% carbon neutral energy supplier, like Bulb. In that case, the carbon impact of their home energy is zero

Pretty much everything we do has a carbon impact. Whilst measuring emissions is never a perfect science, this is a great place to start if you want to understand the carbon impact of your business in these extraordinary times. And if you want to understand your own carbon footprint, head over to our carbon calculator to find out.


If you've been working at home, have you thought about these extra emissions? We’d love to hear from you in the Community.