Work From Home

Introduction

Since March 2020 many people have been working from home due to the COVID-19 pandemic. According to the Office of National Statistics, in April 2020, 46.6% of people in employment did some work at home. Of those who did some work from home, 86.0% did so as a result of the pandemic.

Until recently, organisations that wished to calculate their carbon footprint have tended to ignore home workers – mainly because low proportions of their staff were working from home (meaning the carbon footprint was too small to be worth considering), gathering sufficient data to create a useful report was difficult and methodologies such as the GHG Protocol tend to make work from home (WFH) an optional reporting category. However, since the beginning of the pandemic, with offices shut down and many more staff working at home organisations are starting to ask the question of how to account for this unprecedented change in work habits.

The main impact of WFH for an organisation’s carbon footprint shows up in energy usage. Although travel has also been severely restricted this doesn’t touch on an organisation’s footprint in quite the same way – travel has been reduced, but energy usage has only been displaced.

Energy that, pre-COVID, was used in an office building is now distributed amongst the entire staff, each employee working in a totally different setting. Calculating the change in the carbon footprint of an office being unused is a question of looking at the energy bills for that single location. But estimating the carbon footprint attributable to home working is a different problem.

Many people are now working from a location – their own home – that can be considered “mixed usage” rather than “single use” like an office building. And home already has its own energy and usage demands. It is therefore difficult to accurately assess the impact of WFH because the change is not discrete but incremental.

Basic and Advanced Versions

The basic version of the tab requires only information about the number of Full-Time Equivalent staff in the organisation who are working from home, and some details about the amount of time they spend, on average, working from home. Behind the scenes we use a number of sensible defaults based on national averages and our own experience of talking with organisations that have staff who are working from home since March 2020. There is an option to send all of your staff a link to a simple online survey that will allow you to gather data for a more complete estimate of your organisation's WFH footprint.

The survey should take staff less than five minutes to complete and asks for:

• Their name.
  
• Information about their home – number of bedrooms, principle type of heating and whether they use renewable energy.
  
• How much time they spend working at home.
  
• The equipment they use at home for their work.

Once you have received a number of responses to the survey, you can “ Close” it to new responses. You will then be given the option to “Copy Results to Calculator”. This will take you to the WFH tab in “Advanced” mode. At this point, you can review the results and preform a new calculation of WFH carbon emissions. If only a sub-set (or sample) of staff have responded, and if they are broadly representative of all your staff, then you can enter the total number of staff represented by those who responded to the survey.

Working Time

The average work week is 40 hours over 5 days. It is assumed that lunch break would normally have been taken in the office building – i.e. is still contributing to the employer’s energy usage. In the UK, workers must receive at least 28 days’ paid leave per year – equivalent to 5.6 five day weeks. So it has been assumed that staff work for 46.4 weeks per year.

This means that in an average year, each person working full-time from home for the whole year will work for 1,856 hours.

Office Equipment

The average power rating of different types of office equipment can be used to estimate energy consumption, and hence emissions. The assumed values are:

• Laptop: 20-50W
  
• Desktop PC: 80-150W
  
• Screen: 30-60W (22” to 30” LED or LCD screen)
  
• Laser Printer: in use – 300-550W, standby – 10W
  
• Inkjet Printer: in use – 30-50W, standby – 3-5W

For printing, usage is assumed to be 15 minutes per day with the printer being on standby for the rest of the working day.

We have included a number of fixed elements too:

• Office lighting is assumed to be 89W based on DECC’s “Household Electricity Survey”, and that it is used for a quarter of each working day.
  
• There is also 10W of energy allowed for other “Other equipment” (phone, tablets, speakers, routers, docks, etc.) that might be in use throughout the day.

Heating

The Government publishes data about average annual energy consumption for different types of houses under the National Energy Efficiency Data (NEED) Framework.

In 2021 in the UK most homes (approx. 87%) are heated using gas, with 7% of households using electricity for their primary heating.

Based on the UK Government's Primary energy consumption data tables, for households that primarily use gas for heating, 61.9% of all domestic gas consumption is used for that heating. For homes heated by electricity, 17.1% of total consumption is used for space heating.

A 2013 report for the Department of Energy and Climate Change estimated that on average households in the UK have their heating on for 5.6 months of the year and that the heating is on for an average of 7.5 hours a day.

Given data on average fuel consumption for a particular house type, and average heating usage it is possible to estimate how much energy is used per hour for home heating. For an average 3 bedroom semi-detached house, annual gas consumption is 13,800 kWh of which 8,542 kWh is used for heating. This means over a 170 day (5.6 month) heating period, with heating on for 7.5 hours a day, 6.70 kWh of energy is used per hour for heating. A similar calculation can be carried out for households that use electricity for their primary heating. The Simple version of the WFH tab apportions consumption 92.6%/7.4% to gas/electricity to account for 87 of UK households being heated primarily by gas as mentioned above.

It is then a case of finding the incremental change in heating usage between a WFH day and a non-WFH work day. Once known, this is multiplied by the kWh/hour consumption figure above to give the incremental heating energy consumption figure for working from home.

The 2013 report mentioned above suggests that “Households that are in during the day on weekdays report heating their homes for a longer period of time (median 9.4 hours per day) than households that are not in during the day on weekdays (median 8 hours per day).” This difference, 1.4 hours, is smaller than would be imagined but suggests the incremental effects of working from home are not as high as might be expected. Data that we have gathered to date suggests that people working from home heat their homes for about 2 hours more per day than their non-WFH colleagues, so the calculator uses an incremental heating hours figure of 1.5.

What's Missing?

The only way to get a completely accurate footprint of work from home emissions would be for each staff member to measure actual energy consumption and record it day by day. Even then, it would be almost impossible to sort out what energy usage was from home working and what was from other household activities.

The 360°carbon Work From Home tab therefore only gives a reasonable estimate of home working emissions.

The calculator doesn't take account of the fact that for some people, there will be other people also working from home who “own” a share of the incremental energy usage from the home being occupied all day. If you know for a fact that your worker working from home does not have an incremental footprint, then exclude them from the data – but be aware the other people working from the same home might be doing the same!