Tall buildings: energy hogs, or undercover environmentalists?

One partial solution to the American housing crisis is to build up: that is, to construct taller residential buildings that can accommodate more Americans. But many commentators argue that taller buildings have negative environmental impacts that justify height restrictions. For example, Prof. Kheir Al-Kodmany writes that such buildings “consume lots of steel and cement — manufacturing these materials requires lots of energy and generates large amounts of carbon dioxide.” He adds that construction of these buildings requires a great deal of energy, because of the use of heavy machinery, while the operation of these buildings also consumes massive amounts of power because of their large “electrical, mechanical, lighting and security systems,” as well as the energy needed to heat and cool them. 

Thus, it could be argued that cities should enact strict height limits to prevent environmental degradation. This sort of argument, although not entirely wrong, is incomplete for several reasons.  

Building height does not predict energy use

Not all tall buildings are created equal: some are more energy-efficient than others. 

A 2014 study by the Federal National Mortgage Association (often referred to as “Fannie Mae”), a government-sponsored enterprise created by Congress to facilitate lending, shows that although high-rise properties typically use more energy than other buildings on average, not all tall buildings are equally inefficient. Fannie Mae data shows that the average high-rise building uses 137 kBtu (that is, thousands of British thermal units, a measure of energy use) per square foot, while the average mid-rise building uses 125. But there are wide variations within these categories: some buildings in both categories use over 300 kBtu per square foot, while numerous tall and mid-rise buildings use under 100. Thus, energy use is not a strong justification for restrictive zoning.

The efficiency sweet spot? Mid-height buildings 

Other studies suggest that the sort of mid-rise and somewhat-high buildings that are most common in the denser parts of New York and Chicago (that is, 8-30 story buildings, as opposed to walk-ups or supertalls) can be as or more energy-efficient than walk-ups or houses. A 2016 study by several Norwegian scholars suggests that, from an energy-consumption perspective, the “optimal number of stories are found to be in the range of 7-27” — far more stories than the most anti-height new urbanists (some of whom oppose any building taller than four stories) recommend. 

The authors explained that even though “the embodied energy of buildings is generally increasing with building height” energy needed for heating and cooling may be “lower in tall buildings than in low structures due to a lower envelope area to floor area ratio” — that is, tall, thin buildings that take up less land may need less energy to become warmer or cooler. 

Similarly, a 2025 article by three Canadian scholars concludes that in Toronto, buildings with over five stories had lower per capita greenhouse gas emissions than single-family houses, attached houses or smaller multifamily buildings. The scholars concluded that even though mid-rises and high-rises had significant “embodied” emissions (that is, emissions related to building construction), they had lower emissions related to building operations. 

The authors suggest that other commentators’ focus on construction emissions was misguided because “embodied emissions from buildings and transport infrastructure account for only 7-12% of annual [greenhouse gas] emissions.” But because the authors of this study grouped all buildings higher than five stories together, it is not clear how high the optimal building height is.

An article by several Israeli scholars concludes that for certain building configurations, “up to 8 floors, increasing the number of stories improves the energy consumption.” The authors added that “above 8 floors, an effective plateau is reached and the height of the building has almost no influence on its energy consumption,” thus suggesting that even taller buildings do not consume more energy than a one-or-two story building. However, the Israeli authors do not specify a point of diminishing returns.

Modern tech can shrink buildings’ carbon footprint

Finally, the theory that high-rises are inherently energy-consuming is based on two assumptions: 1) that there is no way to reduce energy use in existing buildings and 2) that newer high-rises cannot possibly be more efficient than older high-rises. The first assumption has been proven wrong in recent years: For example, obsolete boilers and windows can be replaced, and electricity can be substituted for more energy-intensive technologies. 

While it is unclear how common or significant these improvements are likely to be, they are proven to work: One 18-story building in Hamilton, Ontario now uses 65% less energy per square foot than it did in 2018, due to a variety of similar improvements. 

And Al-Kodmany himself has challenged the second assumption in his more recent work. In a 2025 article showing how architects are making tall buildings more energy-efficient, he discusses a variety of energy-efficient reforms affecting them. For example, he writes that some buildings are adopting high-performance concrete, which is designed in a way that “lowers embodied carbon, and makes [such concrete] cost-effective and environmentally friendly.” 

In sum, it is not clear that even skyscrapers are always energy hogs. But even if they are, this is not necessarily true of twenty-story buildings like the Manhattan building where I reside. So why does this matter? Because if North America is going to allow builders to significantly increase housing supply, it needs to give them the flexibility to do so in a variety of ways: smaller buildings where renters and homebuyers want them, but also taller buildings in some places. Otherwise, fewer housing units will be built, and renters and homebuyers will suffer from higher costs and fewer choices.