High density may be a good thing in cities, but tall buildings are not.
It is a standard environmental argument that high densities and tall buildings are greener; it is an excused used in cities like Toronto to approve tall condo towers everywhere. This TreeHugger has tried to make the case that you can have too much of a good thing, and that one should design cities to what I called the Goldilocks Density:
Now, my student Bisma Naeem at Ryerson School of Interior Design points to a number of studies that demonstrate that the higher the building, the more embodied and operating energy required per square unit of measure.
The embodied energy goes up dramatically with building height as well. And this doesn’t even take into account the loss of efficiency in tall buildings, as elevators take up a greater proportion of the floor space.
She found another study from the UK that was also a revelation, looking at office buildings in the UK:
The study set out to answer two questions:
The researchers found that “when rising from five storeys and below to 21 storeys and above, the mean intensity of electricity and fossil fuel use increases by 137% and 42% respectively, and mean carbon emissions are more than doubled.”
There are also the additional pumps for fire protection and water, larger stairwells, and those tuned mass dampers that they are sticking at the tops of buildings, giant balls of embodied energy.
I have often noted that you can achieve very high densities without building very tall buildings; you just have tolook at Montreal, Paris, Barcelona or Vienna to see how lower buildings have much more efficient plans, and can be packed more closely together. I have also noted that high buildings do not necessarily have a very high population density; just look at all those sliver towers in New York.
The real eye-opener about these studies is that when it comes to energy consumption, lower is better.
