It has become trendy in the last few years to talk of ‘net-zero’ buildings, even ‘net-positive’ buildings. While the idea of a building being net-positive on operating energy can be fully implemented given the resources, the idea of ‘net-zero’ or ‘net-positive’ performance on the whole building can be erroneous at best and dangerous at worst.
Erroneous because, like all economic flows of resources, there is a revenue-type component to buildings and a capital-type component. One often trades one for the other and a fully ‘net-zero’ scheme would not be able to do so. By using more thermal mass and/or insulation and converting to passive cooling, one is replacing operating energy with embodied energy. Is the whole picture zero? No. To do that, a building would have to provide all its operating resources while leaving the capital intact.
Dangerous because the concepts of ‘net-zero’ or ‘net-positive’ buildings can make us humans stupidly believe that our human activities, especially construction, is in some ways ‘good’ for the planet, or at least does no harm. This is an arrogant, anthropocentric view of nature, and will be detrimental to our species in the long term. Any reflection on the topic will tell us that the planet will survive humans, not the other way round. To be truly ‘net-zero’ or ‘net-positive’ from a planetary point-of-view would require a building to display the following features:

• Net-zero or -positive on operating electricity and embodied electricity for making and running all the devices and components that make up that project.
• Net-zero or -positive on operating energy and embodied energy for making and running all the devices and components that make up that project (how do you compensate for fuels to heat and make materials by producing extra electricity?).
• Net-zero or -positive on operating water and embodied water for making and running all the devices and components that make up that project (including the lifestyle of its residents, especially food habits, for the life of the project).
• Net-zero or -positive on operating goods and materials and embodied goods and materials for making and running all the devices and components that make up that project (what food do you eat and how is it grown and how does it reach you and how is it processed? And the same questions for all the materials that went into a project).
• Net-zero or -positive in terms of operating resources and embodied resources beyond the above (Is the developed land of the project sustainable and equitable? Did the soil remain pristine? Was biodiversity enhanced? Were chemical fertilizers or insecticides not leached into the soil? Was all additional noise prevented? Did runoff decrease or stay constant? These are not easy parameters to achieve, all together).
• Do all the above AT THE SAME TIME and AT THE SAME PLACE because you cannot trade electricity for heat or heat for water and also expect the planet to not have to manage any better. Neither can you imagine an infinitely large ecological footprint because if you do so then all projects are resource-neutral anyway at the scale of the Universe!

In my practice and travels over the last four decades, I have not come across any building or project that meets all the above criteria, not even one that comes close. Not even the so-called ‘net-positive’ projects.

The sooner we give up the arrogance that we humans are in some ridiculous way, good for the planet, the sooner we will shed our natural anthropocentrism and get to work to create a better life for ourselves, a better life over the long term, respecting that there is always a cost, no matter however small, that nature pays to allow us that comfort, and for which we must profoundly thank her. After all, this is what all spiritual traditions teach us, and what we ignore at our peril.
This is a sort-of restatement of Schrodinger’s version of the second law of thermodynamics: you cannot steal negentropy from nature (which is an ocean of increasing entropy) forever. Death is an axiomatic outcome of life. There is no such thing as net-zero building, it is always finally net-negative.