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The Big Cave

Despite concerns about climate change and environmental impact, the average size of a house in the United States has risen nearly 40% since 1973.

Photo by ErikaWittlieb

william schlesinger
President Emeritus, Biogeochemist

America is the land of the big—Big Houses, Big Cars, Big Macs, and Big Dreams. The average new house in the U.S. has 1000 square feet (93 m2) per occupant.  Other world citizens get along with a range of 161 to 430 square feet.

I suppose our passion for the big house goes back to the Paleolithic, when the recognized leader of society possessed and defended a big cave. Thus, it is perhaps natural that Bill Gates lives in a house of 66,000 square feet.

Of course, big houses require lots of heat and air conditioning. It is not surprising that heating buildings in the U.S. accounts for 13% of our carbon dioxide emissions and almost 40% of our use of electricity. I shake my head every time I pass a McMansion, when it has a Tesla or Prius in the driveway.

The energy used to manufacture and deliver the materials for new house construction amounts to 9% of residential emissions in the U.S.  The choice of construction materials matters; production of cement (0.77 tons CO2/ton) and steel (2.2 tons CO2/ton) result in emissions of CO2 to the atmosphere whereas wood removes and stores it.  Size also matters; apartments are more efficient than single-family homes. To reduce carbon dioxide emissions from the residential sector, one recent study finds that it is much more effective to renovate existing houses than to replace them. Upgrades to insulation and HVAC systems pay off.  Heat pumps are generally preferable to most older furnaces.

The good news is that the trend to larger houses seems to have diminished slightly in recent years. Yet, despite concerns about climate change and environmental impact, the average size of a house in the United States has risen nearly 40% since 1973, while the median household size has dropped from 3.5 to 2.5 people over the same period.  We may focus our attention on transportation, but residential energy makes a huge contribution to energy use.

In our home, we have about 700 square feet per occupant.  Somehow, we get by without stumbling over one another, and it is so much easier to keep a small cave warm and clean.


Berrill, P., E.J.H. Wilson, J.L. Reyna, A.D. Fontanini and E.G. Hertwich. 2022.  Decarbonization pathways for the residential sector in the United States.  Nature Climate Change 12: 712-718.

Ding, G. and X. Ying. 2019.  Embodied and operating energy assessment of existing buildings—demolish or rebuild.  Energy 182: 623-632.

Schlomer, S. et al. 2014.  Technology -specific coast and performance parameters.  Annex III in Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report.  Cambridge University Press.


william schlesinger
President Emeritus, Biogeochemist

William Schlesinger is active in communicating science to policy makers and media. He has testified about environmental issues in Congress and in state houses, and has been featured in media including NOVA, the Weather Channel, Discover, National Geographic, and the New York Times.

He discusses a range of environmental issues in his weekly blog, Translational Ecology.

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