On the Massive Carbon Savings of Gentle Density

A thought experiment compares the carbon impact of three new single family homes with the same block if it contained a duplex, a triplex, and a fourplex.

Read Time: 1 minute

June 13, 2019, 9:00 AM PDT

By Philip Rojc @PhilipRojc

Los Angeles Bungalow Court

Los Angeles / Wikimedia Commons

If it were legal everywhere, Michael Anderson writes, gentle density would confer massive carbon savings and ease the transition away from fossil fuels. 

To illustrate, Anderson poses a thought experiment where three large new homes are constructed on one block, while a duplex, triplex, and fourplex are built on a site of the same size. "If we compare these two blocks after all the new homes are complete, the housing-related carbon emissions per household of the Plex Block will be about 20 percent lower," he writes.

It makes sense that smaller living spaces cost less carbon (and dollars) to heat in the winter and cool in the summer. And in the case of the McMansion, most of that space isn't even lived in.

Anderson also notes that when "missing middle" housing is permitted, the positive environmental effects extend to transportation. "This density effect is probably strongest if it's creating new options for living in a transit-rich, walkable area specifically for people who want to live a low-car life but couldn't previously afford that sort of neighborhood."

Friday, June 7, 2019 in Sightline Institute

Green bike lane with flexible delineators and textures paint in Hoboken, New Jersey

America’s Best New Bike Lanes

PeopleForBikes highlights some of the most exciting new bike infrastructure projects completed in 2022.

January 31, 2023 - PeopleforBikes

Walkable, mixed-use neighborhood in Barcelona, Spain

Conspiracy Theorists Discover the 15-Minute City

USA Today debunks the false claim that the United Nations’ call for enabling 15-minute cities is a coded plan to institute ‘climate change lockdowns.’

February 8, 2023 - USA Today

Aerial view of MBTA commuter rail station in Concord, Massachusetts among green trees

Massachusetts Zoning Reform Law Reaches First Deadline

Cities and towns had until January 31 to submit their draft plans for rezoning areas near transit stations to comply with a new state law.

February 1, 2023 - Streetsblog Mass


Washington Could Legalize Single-Staircase Buildings

Supporters of ‘point access blocks,’ which are common in Europe and other parts of the world, say the design maximizes living space and lowers the cost of construction.

February 8 - The Urbanist

View of downtown San Francisco from top of windy street at sunset with Coit Tower in distance

San Francisco Housing Plan Gets State Approval

The city cleared a major hurdle as its housing plan, which paves the way for 82,000 new homes by 2030, is certified by the state.

February 8 - KALW

Green Line, Los Angeles

Rail Transit Plans Would Connect L.A.’s South Bay to the Regional Rail System

Two new transit extensions promise several new routes for South Bay residents to access the Los Angeles region’s transit system.

February 8 - The Source