Measuring emissions from homeworking

Homeworking is now a permanent feature of working life for many businesses, and with it comes a carbon footprint consideration that's easy to overlook.

When employees work from home, the energy they use for heating, lighting, and equipment becomes part of your business's responsibility, because it's being consumed for business purposes. The good news is that measuring and reducing these emissions is more straightforward than you might think.

In this post, we're walking through how to calculate your homeworking emissions, how to improve the accuracy of your estimates, and what you can practically do to reduce them, so your carbon footprint tells the full story of your business's impact.

Why do homeworking emissions matter for your business?

Since the pandemic, hybrid working has become the norm. The average number of days worked from home in the UK is now 1.8 per week, higher than the global average of 1.3. While this shift has likely reduced your premises energy use and employee commuting emissions, it has also transferred a portion of energy consumption into your employees' homes.

Under the Greenhouse Gas Protocol, these emissions fall within Scope 3 of your carbon footprint - specifically as a sub-category of Category 6 - Employee Commuting. Including them gives a more complete and credible picture of your business's impact, and increasingly, it's what stakeholders and reporting frameworks expect to see.

The methodology that has become the industry standard for estimating these emissions is EcoAct's Homeworking Emissions Whitepaper, which also forms the basis of the UK government's (DESNZ) official homeworking emissions factors.

How do you calculate a basic homeworking emissions estimate?

Getting a baseline estimate is simpler than most businesses expect. The starting point is a straightforward calculation: total FTE hours worked from home x DESNZ homeworking emissions factor = estimated homeworking emissions

The DESNZ homeworking emissions factor, published annually as part of their conversion factors dataset, covers office equipment and heating. It's calculated using EcoAct's base case assumptions, accounting for average heating patterns, electricity use from lighting, and laptop consumption. Because DESNZ updates it annually using the most current fuel and electricity data, it's a reliable and recognised starting point.

To use it, you'll need:

• The number of employees working from home
• An estimate of average weekly homeworking hours
• The current DESNZ homeworking emissions factor for the relevant year

This gives you a credible, auditable baseline, which is exactly what you need to start tracking progress over time.

How can you improve the accuracy of your estimate?

The base case calculation is a solid starting point, but there are simple ways to make your estimate more specific to your workforce. Collecting a few additional data points from staff - through a short survey, for example - can meaningfully improve accuracy.

At Green Business, the survey approach used with our clients collects information on:

• Electricity provider and fuel mix - whether staff are on a green or standard tariff
• Heating system - gas, electric, heat pump, heating oil, or other
• Number of people present at home during working hours - whether working or not, as this affects heating patterns

These data points allow emissions estimates to better reflect each employee's actual situation, rather than relying solely on national averages. It also opens up a valuable conversation with staff about their own energy use, which is important, because engaging your team is central to actually reducing these emissions.

What are the most effective ways to reduce homeworking emissions?

Because your business has limited direct control over what happens in employees' homes, reduction depends heavily on engagement, encouragement, and making it easy for staff to make better choices.

Here are some key levers to focus on:

• Home heating: encourage staff to heat the room they're working in rather than the whole house. An oil-filled radiator with a thermostat works well for individual rooms, or focus on heating the person directly (our Founder Tim swears by his heated gilet!)
• Lighting: switching off lights when not in use and switching to LED bulbs can make a noticeable difference; consider offering small financial incentives to encourage the switch
• Equipment: turning off IT equipment when not in use (rather than leaving it on standby) and avoiding overcharging devices; where possible, encourage staff to choose energy-efficient office equipment
• Electricity tariffs: most suppliers now offer green products, but not all green tariffs are equal. Encourage staff to look for suppliers that back their supply with Power Purchase Agreements (PPAs) where possible

Small changes across a workforce can add up to a meaningful reduction, and starting these conversations builds a culture of environmental awareness that extends well beyond the home office.

What else might be missing from your homeworking emissions picture?

The approach outlined above captures the most significant and measurable elements of homeworking emissions - heating, lighting, and office equipment - but there are other areas of the homeworking carbon footprint that are harder to estimate, allocate, and influence.

Two worth keeping on your radar as your reporting matures:

• Waste: the packaging, food waste, and general household waste generated during working hours
• Food and drink: the emissions associated with meals and drinks consumed at home during the working day

These are trickier to quantify, and for most SMEs, the effort required to estimate them precisely isn't yet proportionate to the insight gained. That said, home office emissions are a genuinely useful entry point for engaging staff on their wider environmental impact, and the conversations you start here often lead to broader awareness and behaviour change across your team.

Find out more about how our carbon footprinting service can help you build a complete picture of your Scope 3 emissions, including homeworking.