Energy Intensity Less in Single-Family Homes Than High-Rises

An implicit assumption in many of the briefs for Smart Growth is that multi-unit dwellings are more resource-efficient than single-family homes. However, Department of Energy Tables show that this is not true, at least not on the basis of energy per square foot of living space.

Table 8c. U.S. Residential Energy Intensity Using Weather-Adjusted Primary Energy by Census Region and Type of Housing Unit, (1000 Btu per Square Foot)

2001: Northeast Region

73: Total

67: Single-Family Detached
69: Single-Family Attached
79: Apartments in Buildings with 2 to 4 Units
98: Apartments in Buildings with 5 or More Units

Energy Intensity: The ratio of energy consumption to a measure of the demand for services (e.g., number of buildings, total floorspace, floorspace-hours, number of employees, or constant dollar value of Gross Domestic Product for services).

So why might this be? The San Francisco Bay Guardian explains (10/31/07):

…high-rises use energy in ways that single-family homes don’t — for example, in thousands of elevator trips from top to bottom every day. According to a study found on the US Department of Energy’s Web site, elevators consume up to 10 percent of the total energy used to maintain tall buildings. Furthermore, these buildings are usually climate controlled (in part to counteract the heat created by their elevators), whereas opening and closing windows can more effectively regulate temperatures in single-family houses and low-rise units. High-rise buildings also include common areas that often leave lights burning 24 hours a day.

Electricity Week further fleshes out the picture (10/8/07):

Two years ago, EnergyAustralia and the NSW Department of Planning took an in-depth look at energy use in high-rise apartments and were surprised to find that some of the new developments were the worst energy performers. Their analysis found that high-rise residents were responsible for about 10.4 tonnes of carbon dioxide per resident per year, compared with nine tonnes for detached homes and 5.1 tonnes for townhouses.

High-rise costs up to 50pc more than for traditional homes: A big energy sucker could be common areas, some of which had lights burning and air-conditioning churning 24 hours a day. This could cost each apartment owner more than $1500 per year at some large complexes. This compared with about $1000 per year for the total electricity bill of an average residential household.

The Sydney Morning Herald adds (5/30/06):

When divided by the average number of residents in different types of housing, flat-dwellers came out the highest energy offenders – 5.4 tonnes of greenhouse gases a person, compared with 2.9 tonnes for residents of detached homes.

Other reasons for higher energy intensities in residential high-rises can include “parking garage fans and a building code requirement that building air must be completely exchanged every three hours – air that must be heated in winter and cooled in summer.” (Energy Solutions Alberta)

We also speculate that costs that are borne by an entire complex, such as lighting and heating common areas, may be less closely monitored than costs that fall on a single household. Since turning down your personal thermostat is simple and will directly save you money, you’re more likely to do it than lobby your building managers to make the common areas colder.

Maybe John and Jen Homeowner who like a house with a yard aren’t such bad folks after all.

See also:

Springfield Republican: “Home builders see boom in energy saving construction” (7/13/08)
While the housing market is in the midst of a historic decline, one segment of it is thriving: Green homes…

Their electric bill [for a single-story, 1,300-square-foot home in Colrain with three bedrooms and two bathrooms] averages $10 to 15 per month, less in the summer when the days are longer and brighter, and they have bought about 400 gallons of propane since they moved in. Propane has ranged from about $2.20 to $3 a gallon in the last year. Typically, a similar sized home would use about 1,100 gallons of propane in a year.

“I think the phrase – near-zero net energy – is proper. We didn’t use no energy. But we did use less than a conventional house,” McDonough said.

Comment on Planetizen (10/23/07)
With midrise buildings, you can plant deciduous trees to shade the buildings during the summer and expose them to the sun during the winter, reducing the burden of heating and cooling. This doesn’t work for highrises, which are much taller than trees.

Los Angeles Times: “Developing a hotter L.A.” (9/9/07)
Los Angeles’ accelerating quest to create centers of higher population density — especially downtown, in Hollywood and in Mid-Wilshire — may be on a collision course with California’s crusade to slow global warming by reducing its greenhouse gas emissions. And the potential trouble comes from an unlikely source — buildings…

One effect of high-density development that can potentially increase energy consumption is a phenomenon known as the “urban heat island…”

Packing taller residential buildings closer together to increase density, without making room for significant areas of green space, such as parks or shaded plazas, only worsens the effect…

…heat-island studies of such cities as London, Athens, Tokyo, Beijing, Phoenix and Los Angeles have not only shown the problem worsening but have documented the rising level of energy consumption associated with it. The greater the density and the less green space nearby, the more severe the urban heat island can become…

A study of Los Angeles by the Heat Island Group at the environmental energy technologies division of the Lawrence Berkeley National Laboratory suggests the amount of energy involved. It estimated that “the demand for electric power rises nearly 2% for every degree Fahrenheit the daily maximum temperature rises.”

EPA: Urban Heat Islands

Metro Portland’s Long Experience with Smart Growth: A Cautionary Tale
Restrictive growth policies actually caused increased suburbanization in Portland, which now has the 10th greatest suburbanization rate in U.S. As home prices went up in the site-restricted metropolitan area, families moved further out to find affordable housing. Portland actually has rates of suburbanization that are close to that in metropolitan areas with so-called “white flight” and other central city problems. This phenomenon increases vehicle miles traveled as it lengthens commutes…

Denser multi-family housing requires more costly construction techniques, further increasing the cost of housing…

The notion that potential homeowners would prefer to pay the higher cost of high-density housing as an alternative to the traditional home/yard/neighborhood environment style of raising families is wrong. The percentage of families moving to the Portland area that buy or rent within the UGB [Urban Growth Boundary] has fallen dramatically since site restrictions were implemented…

Our Column in Today’s Gazette: The Hidden Risks of ‘Smart Growth’
Portland discovered that people tend to hang on to their cars, even as density increases. The city’s population density is about 45 percent higher than the average of the largest 200 metro areas. Its “vehicle miles traveled” per square mile is 42 percent higher.

Besides hoping that people will stop driving, another critical assumption of smart growth advocates is that it’s cheaper to add density to existing urban infrastructure than to add infrastructure to new areas. Harvard researchers Alan Altshuler and Jose Gómez-Ibáñez find that the reverse is true.

Wendell Cox: “METROPOLITAN DENVER AT RISK: How Densification Will Intensify Traffic Congestion, Air Pollution and the Housing Affordability Crisis”
What is in vogue is not always correct…

Planners and architects in the 1950s thought that 20-story public housing projects were the answer — the same projects that are being imploded around the country today…

Pictures of Northampton Streets at Various Densities