120 Years of U.S. Residential Housing Stock and Floor Space

<div><p>Residential buildings are a key driver of energy consumption and also impact transportation and land-use. Energy consumption in the residential sector accounts for one-fifth of total U.S. energy consumption and energy-related CO₂ emissions, with floor space a major driver of building energy demands. In this work a consistent, vintage-disaggregated, annual long-term series of U.S. housing stock and residential floor space for 1891–2010 is presented. An attempt was made to minimize the effects of the incompleteness and inconsistencies present in the national housing survey data. Over the 1891–2010 period, floor space increased almost tenfold, from approximately 24,700 to 235,150 million square feet, corresponding to a doubling of floor space per capita from approximately 400 to 800 square feet. While population increased five times over the period, a 50% decrease in household size contributed towards a tenfold increase in the number of housing units and floor space, while average floor space per unit remains surprisingly constant, as a result of housing retirement dynamics. In the last 30 years, however, these trends appear to be changing, as household size shows signs of leveling off, or even increasing again, while average floor space per unit has been increasing. GDP and total floor space show a remarkably constant growth trend over the period and total residential sector primary energy consumption and floor space show a similar growth trend over the last 60 years, decoupling only within the last decade.</p></div

Estimation of new housing completions (construction) of 3 building types, 1891–2010.

<p>Sources: Compiled from Historical Statistics of the United States, Colonial Times to 1970—Part 2; U.S Census Bureau, New Residential Construction; Manufactured Homes Survey (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.s004" target="_blank">S2 File</a>).</p

Absolute household size and decompositions of population and floor, 1891–2010.

<p><b>Top</b>: absolute household size, derived as the ratio of population and number of units. U.S Census Bureau data are shown for comparison. <b>Center</b>: decomposition of population into number of homes and household size. <b>Bottom</b>: decomposition of floor space into population, floor space per home and household size. In two lower figures, variables have been normalized to 1 at start of period (1891), so y-axis is unitless. Decomposing household size into the 3 building types was not possible due to insufficient population data per building type.</p

Log-linear relationship between floor space per capita and GDP per capita.

<p>Sources for GDP: for 1969–2010, a compilation of historical data by the Unites States Department of Agriculture was used [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.ref022" target="_blank">22</a>]; to extend data back to 1890, the Maddison Project was used [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.ref023" target="_blank">23</a>].</p

Floor space averages.

<p>Estimated as average of floor space data from the 1999–2011 period. Source: American Housing Survey (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.s006" target="_blank">S4 File</a>).</p

Estimated floor space average by building type, 1891–2010.

<p>Ratio of total estimated floor space and housing stock time-series.</p

Single-and multi-family average floor space per unit for 8 vintages, from survey years 1985–2011.

<p>Dotted lines represent averages computed before vintage period is over. Discontinuities in 1995–1999 are possibly a result of methodology changes. Average floor space for both building types used in this work corresponds to the average of survey year data for 1999–2011. Source: American Housing Survey (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.s006" target="_blank">S4 File</a>).</p

Total energy consumption and total energy consumption per square foot, compared to floor space.

<p>Total energy includes all end-use fossil and renewable sources, electricity, electric conversion and distribution losses. Source for energy: EIA Monthly Energy Review [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134135#pone.0134135.ref001" target="_blank">1</a>].</p