Forget About Banning Glass Towers, Instead Demand Tough Standards Like Passivhaus

Most glass buildings are a problem, but just banning them is the wrong solution.

James Tapper writes in the Guardian that "leading architects and engineers are calling for all-glass skyscrapers to be banned because they are too difficult and expensive to cool." That's not quite what they are saying, but it's confusing.

“If you’re building a greenhouse in a climate emergency, it’s a pretty odd thing to do to say the least,” said Simon Sturgis, an adviser to the government and the Greater London Authority, as well as chairman of the Royal Institute of British Architects sustainability group. “If you’re using standard glass facades you need a lot of energy to cool them down, and using a lot of energy equates to a lot of carbon emissions.”

RHW.2 in Vienna/ Lloyd Alter/CC BY 2.0

But is being all glass actually the problem?

This all-glass building in Vienna is built to the Passivhaus standard, which sets absolute limits on energy consumption and yet it still is cool inside. I could understand when the Mayor of New York says he is going to ban all glass buildings; he's not a building scientist and often throws out a glib phrase (and backtracked). I note that Simon Sturgis used the word standard, but it confuses the issue. They should all just come out and demand the toughest standard of efficiency and let the architects and engineers figure it out. I described how they did it at the RH2 building in Vienna:

The building’s energy concept is compelling: energy is provided by a photovoltaic system as well as a combined heat, cooling and power plant. Even the waste heat from the data centre is re-used, with cooling partly coming from the Donaukanal. The decisive factor in achieving the passive house Standard was the radically increased efficiency of the facade, the building component connections, the mechanical systems – and even the coffee machine. In combination with optimised shading equipment, the heating and cooling demand was reduced by 80% compared to conventional high-rise buildings.

© Jessica Grove-Smith on top of 211W29/ Monte Paulsen

Writing for the International Passive House Association, Jessica Grove-Smith and Francis Bosenick explain how Passivhaus buildings stay cool.

It’s all about the design and keeping the heat out! For high summer comfort this means understanding the solar loads and the ventilation strategy to ensure that temperatures inside the building do not exceed 25 °C for more than 10% of hours annually...If the climate is too hot to be able to ensure comfortable conditions with only passive cooling means, Passive House buildings are kept cool with an efficient cooling system. Optimising the design and prioritising passive cooling strategies makes sure that the cooling load is kept very low.

People think of insulation as something that keeps heat in, but as Dr. Feist notes, "Insulation does not create any additional heat; it only reduces the heat exchange between systems with different temperatures. Therefore, it also protects a cool system from gaining heat from the surroundings."

Grove-Smith also notes that you can't just think about the building, but the stuff you bring in or put inside. "It is an integral part of the Passive House concept to minimise the energy consumption of all services in the building and encourage the use of efficient equipment throughout."

© Juraj Mikurcik/ a passivhaus in UK

Evidence from the recent heat wave shows that it works. It's not an office building with all kinds of interior loads, but we've shown Juraj Mikurcik's Old Holloway Passivhaus and it just got cooked. Juraj writes: "Over the last few days, when outside temperatures peaked at 29C, the house remained comfortably below 23.5C. It’s difficult to describe the feeling of walking in from the sweltering heat, but it’s just lovely. So how is this achieved? Most of the windows are externally shaded, so solar gains are really minimal."

Lloyd Alter/ note the shadows on the windows and building/CC BY 2.0

We saw also how Stas Zakrzewski kept the heat out of 211W59 in Manhattan – lots of insulation, careful control of window size with clever shading. This building is meeting the same Passivhaus standard that the Vienna building is, just in a different way.

So let's stop with all the "ban glass buildings" talk. Just demand a tough standard that every building has to conform to. It exists, lots of architects and engineers know how to do it, and it's called Passivhaus.