Tiny homes to save the climate?

Original with more interactive features at "Medium"

In a new study by the International Resource Panel, we show that reducing per capita floor space, compared to a business-as-usual development, can substantially reduce the demand for emissions-intensive construction materials, in addition to reductions of energy required for heating and cooling, saving billions of tons of greenhouse gas emissions in the G7 countries, as well as in China and India. For the G7, the reduction in floor space demand is more impactful than the sum of all other investigated measures: using wood instead of reinforced concrete as a construction material, increased recycling and reuse, constructing lighter buildings through smarter designs, and reducing construction waste. No wonder The Daily Telegraph picked up this aspect of our work with a provocative story.

My first reaction was exasperation at the exaggeration by the news coverage: we just assumed a 20% reduction of floor space over what would otherwise be generous scenarios for further development — hardly the radical size reduction that the ‘tiny home’ movement promotes. In many countries, this would still be more than the 35 m2 that the average English calls ‘Sweet Home’.

Neither are free-standing singles-household tiny-homes a particularly good idea. Our research shows that sharing walls with others makes it easier to each use less floor space, saves building materials, and conserves energy. In addition, it is much nicer to live with others, as The Economist describes in this week’s story of people moving in with each other to have more company at the time of social distancing.

Short of taking on flat mates, our research showed that living in a multi-family house was much more environmentally friendly than living in a detached single-family house. It saves both materials and energy.

So, the image of the tiny house, while catchy, does not really capture our story. Rather, it is the image of a compact settlement drawn in The Weight of Cities, another Resource Panel report. It found that a well-articulated urban morphology with a mixture of residential and commercial space, flats and work places, provided for the most attractive living conditions, in addition to reducing resource use and transport needs.

Will people accept having less living space?

We seem to have a knee-jerk reaction against the idea of the government limiting our floor space. Who wants that? What about consumer choice? Right now, however, various policies encourage and subsidize increased home size. Is government interference more acceptable when it increases resource consumption and pollution?

Choices are influences by numerous factors, including availability, costs, culture, and social norms. Home sizes differ widely across and within mature developed economies, influenced by all sorts of factors, not least tax policy and land use planning/zoning rules. Our report documents many policies encourage larger homes.

• Tax rules encourage investment in residential real estate independent of size, giving incentives to the well-off to purchase ever larger homes through things like mortgage interest tax credits and mortgage guarantees, for example in the US. Other benefits may include reduced wealth taxes on homes and exemptions of the property value increases from the income/capital gains taxes.
• Transaction costs such as the UK stamp duty, a fee that you pay to register a change in home ownership, impose costs on moving to smaller homes, e.g., when you no longer need a large home because children move out or partners separate.
• Zoning rules and tax laws favor single-family over multi-family homes, e.g. by restricting the size or height of the building, or making it easier and cheaper to obtain mortgages. Single family residences are normally larger, and less energy efficient, than multi-family homes.

Current government policies on home ownership are not only environmentally harmful, they are regressive: they increase the cost of living of the less well-off and young, and the wealth of those who are well-to-do and older.

Imagine now that the government changes planning rules and tax laws, and that social norms change to favor multifamily homes, co-housing, and generally less but more equitably distributed residential floor space. What would happen is that fewer new residential buildings need to be constructed. It would be easier to meet the need for new building space using recycled building materials and renewable resources. Our modeling of material stocks and flows indicates that emissions associated with material cycles could be reduced by up to 80% in G7 countries, a truly astonishing reduction.

Resource Efficiency and Climate Change

PS: The Daily Telegraph had a follow-up story, where they interviewed mostly young Brits who had moved into tiny homes. In a mixture of curiosity and astonishment, they report that these young people actually enjoy living in tiny homes. :-)