Regional and Urban Design Committee

Two large scale cold snaps sweeping over much of the US in one week are the perfect occasion to consider our heating cost, where energy is used, what building energy consumption is and challenge some preconceived notions about energy and buildings.

Infrared image of a whole house in winter condition. Yellow and red are areas of biggest heat loss (Internet)

Could it be that what it takes to be comfortable on an extremely cold winter day may depend less on how well insulated the dwelling is and more on where it is located? And I don't mean Fargo or Miami, I mean rural, suburb or city.

Just consider how much more energy a freestanding building is likely to use than an apartment, how much more efficient a narrow rowhouse must be compared to a mansion and you get a hint. Dwellings that are stacked or bunched should use less energy and are much more likely to be found in cities. Indeed, the Department of Energy 2011 report states that apartments use about half as much energy than freestanding houses (section 2.5). The kicker is, that they also say that this is because they are much smaller. The report also observes that  "although multi-family homes used the least energy per household, they consumed the most energy per square foot of heated floor space, at 78,300 Btu". This is certainly a counter intuitive fact for which no reason is given. It may have to do with poor controls, user behavior or similar factors that have little to do with physics. (a detailed discussion of the apartment energy intensity here. Main finding: The energy per square foot measure gets distorted for smaller units because the large consumers such as refrigerator, washing machine, hot water heater etc. are size independent and weigh heavier on a smaller unit than a big one). So does city living save you heating fuel? We will get back to this further down the article.