The Sustainability Implications of Single Occupancy Households

The Sustainability Implications of Single Occupancy Households

Fresh thinking is needed on how we share spaces and services in dwellings and cities

Single occupancy households consume more resources per capita, and demographics suggest single occupancy is now widespread in many countries. Environmental policies need to adjust to include per capita consumption to account for occupancy and efficient use of resources. Diana Ivanova, Tullia Jack, Milena Büchs and Kirsten Gram-Hanssen explain how the sharing of resources at domestic, neighbourhood and urban scales can have positive environmental and social impacts.

What do Oslo, Berlin and Paris have in common? 50% of households in these three European capital cities are occupied by single residents (Eurostat, 2018). Over the past 50 years, household size has been shrinking, not just in Europe but also in both developed and developing countries (Bradbury et al., 2014; Ortiz-Ospina, 2019). The actual number of single occupant households is predicted to rise substantially in the coming decades (Jennings et al., 2000). Affluence is crucial, with rising incomes in many countries likely to further encourage living alone (Ortiz-Ospina, 2019; Esteve et al., 2020).

<strong>Figure 1.</strong> Distribution of EU household carbon footprint by household size. The percentage labels show the share of the footprint across 1-person, 2-person, 3-person, 4-person and 5 or more-person households. The y-axis represents the average carbon intensity per capita, and the x-axis - the number of people who live at such household size. Results and labels were adapted from Ivanova & Büchs (2020).
Figure 1. Distribution of EU household carbon footprint by household size. The percentage labels show the share of the footprint across 1-person, 2-person, 3-person, 4-person and 5 or more-person households. The y-axis represents the average carbon intensity per capita, and the x-axis - the number of people who live at such household size. Results and labels were adapted from Ivanova & Büchs (2020).
Smaller households, coupled with trends toward larger houses, increase per capita energy and resource consumption, domestic waste and production of GHGs  (Ellsworth-Krebs, 2020; Bradbury et al., 2014; Liu et al., 2003). Regardless of how many people live in them, most Western households have white goods (e.g. refrigerator, cooker and washing machine) and conditioned space (Yates, 2018). In Sweden, where the majority of apartment blocks once shared a laundry room, now more than 80% of newly built apartments have their own washing machine (Jack, 2019). Smaller households miss out on sharing potential for heating, cooling, cooking and other home devices (Ivanova & Büchs, 2020). Shrinking household size is a fundamental challenge for keeping carbon emissions down (Figure 1).

There are also social costs associated with living alone. Some evidence suggests that single occupant households have the lowest life satisfaction among all household types (ONS, 2019; Gaymu et al., 2012). They are more likely to rent, have higher housing costs, less savings and thus decreased financial security (ONS, 2019). Not everyone who lives alone is lonely, but those that are may show more signs of anxiety and depression (ONS, 2020). There may also be increased health and death risks, particularly among elderly women (Harvard Health Publishing, 2012).

Living alone at various life stages

How do so many people end up home alone? Some common paths to living alone include young people leaving home to study or work, couples living apart for longer before moving in together (if at all), the dissolution of a relationship, or death of a partner. 

Once a person lives alone, they are more likely to continue living alone (Chandler et al., 2004). This is especially the case for women (Liu et al., 2020). Studies show that women enjoy time alone more, have more satisfying friendships, and spend more time pursuing their interests than men do (DePaulo, 2019). Furthermore, once women get a taste for living alone, they are more concerned about doing more than their fair share of chores and caring for others.

The reasons why people live alone vary with life stage. There is a transitional phase early in life, in which forming a partnership or childbearing is delayed (Liu et al, 2020) in order to focus on education or start a career. In that period, it takes longer for men to move in with partners compared to women (Esteve et al., 2020). The gender trend reverses dramatically among the elderly, when the chances of women living alone are 2-4 times higher compared to those of men in Europe and North America (Esteve et al., 2020). At older ages, trends around the lengthened life expectancy and dissolution of partnerships tend to be the main drivers behind more elderly living alone.

 A Canadian panel study examining the nature of living alone in a cohort aged 35-59 provides some important insights about increased solo living among middle-aged adults (Liu et al., 2020). Higher age, duration of living alone and not having a partner as well as living in an apartment increase the likelihood of keeping one’s solo living status. The role of income may be contradictory as higher income increases the affordability of solo living, but it also increases one’s attractiveness to potential partners. Other cultural and social factors may play a significant role, especially where living alone is voluntary and stable throughout the life course.

Policy implications

Despite evidence that living alone has significant sustainability implications, research and policy still emphasise smart technologies and buildings. To meet sustainability goals, GHG emissions accounting, assessment and management currently focus on design, construction and operation of building stocks (cf. Lützkendorf, 2020). This approach is insufficient to curb increasing household consumption (Gram-Hanssen et al., 2018).Building sustainability is important, but so is minimising resources required to provide services (e.g. heating, cooling, light, etc.) per person rather than per building. Policy needs to focus on how buildings are used, including how many people live in them.  Key policy and research questions revolve around how other forms of living, (e.g. shared or co-housing, or tiny apartments) can be included in these metrics to reduce environmental impacts.

A policy focus on sharing can also extend to the cityscape, as services are often provided outside the home. Households may not need a car if public transport is available; public parks and greenspaces reduce the desire for private gardens; gyms, laundromats, restaurants and cafés, libraries and leisure facilities offer alternatives to in-home facilities; and co-working spaces to the home office. Sharing can be both simultaneous i.e. using the same spaces and resources at the same time, and sequential i.e. using spaces and resources at different times for maximum utility (Yates, 2018).

Sharing becomes increasingly viable as urban density increases. Sharing at the city level has exciting potential for reducing dependency on individualised resource ownership at the household level, and simultaneously reducing pressure on house size. Democratising ownership and governance of sharing practices are also key (Schor, 2016) in order to keep agency close to the end user and tailor more adequately to their needs.


Diana Ivanova and Tullia Jack are both funded by the EU’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie international fellowship, grant numbers 840454 and 891223. Milena Büchs receives funding from UK Research and Innovation, Centre for Research on Energy Demand Solutions, Grant number EP/R035288/1.


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