Shiny new smart buildings are wonderful. They have energy efficiency built in to provide cost-saving and reduce environmental impact, they apply lighting and environmental controls to ensure all occupants are comfortable and productive, and they offer a wide variety of health, safety, and security benefits. These buildings offer a glimpse of our high-tech future with sensor-rich, data-driven, and intelligently-controlled indoor spaces designed for the occupant experience and the protection of the environment. New smart buildings only make up a tiny percentage of total building stock, however, less than 1% by some calculations, leaving the vast majority of buildings old, dumb, and highly energy inefficient.

Buildings account for approximately 40% of total energy consumption, produce around 40% of total carbon emissions, and generate about 40% of our landfill waste. Smart buildings were supposed to be the solution for that staggering impact that buildings have on the environment, but even if every new building was smart it would still take centuries to replace old inefficient buildings with shiny new greenfield constructions. Smart buildings are still the solution but new buildings are not. If we are to fully address the environmental issues posed by buildings we must focus on retrofitting existing building stock with energy efficiency technology, and that will also bring a host of occupant-centric benefits to our many legacy structures.

“Different buildings present different levels of opportunity to fine tune them. Generally speaking, when we talk about making an older building energy efficient, we think about the envelope: the windows, walls, door openings, etcetera,” says Rebecca Berry is the president of Finegold Alexander Architects. “We want to get away from electric resistance heat like electric radiators, which are not very efficient and very expensive to run, and use variable flow electric technology, like heat pumps. Heat pumps are great as long as you have a good building envelope.”

Older buildings were often designed to breathe, using porous materials like stone and concrete that allows heat to escape and fresher air to seep in, and with small windows to reduce solar radiation of indoor spaces. This was great in the old days but since the proliferation of air conditioning in buildings around the world, these porous materials have become an inefficiency problem. Newer buildings, on the other hand, often build their envelopes with less porous materials like glass and steel allowing for bigger windows that bring natural light and views to improve occupant wellbeing. These buildings completely depend on air conditioning to ensure occupant-friendly temperatures in sun-soaked offices, which comes with its own energy cost.

“Buildings built before the popularity of air conditioning had openable windows, ceiling fans, and passive strategies for cooling like porches. Thermal comfort is now dependent on high energy use,” says Tamar Warburg, director of sustainability at Sasaki. “Before you begin any building project, you have to consider the carbon embedded in the materials, as well as the operational carbon in things like heating systems. Consider the source of the energy, not just the amount. Don’t just look at the investment cost, look at the overall lifetime cost and determine: where’s the break-even point?”

Embedded carbon, or embodied energy, aims to find the sum total of the energy necessary for an entire product lifecycle, and for the buildings that includes raw material extraction, transport, manufacture, assembly, installation, deconstruction as well as secondary resources. Meaning, the building that stands ready for demolition carries that embodied energy and the process of demolition largely wastes that energy — unnecessarily in the eyes of sustainability. So, while shiny new smart buildings operate much more efficiently than our existing old building stock, the simple fact that these new buildings must be constructed, and often after the demolition of older buildings, means that new buildings are not as green as existing ones.

“A lot of thoughtful, sustainable building is happening today, especially along the coasts in California and the Northeast, the Pacific Northwest, Chicago and other places,” says Warburg in an article on Forbes, but “the most sustainable building is the one you don’t build. If we re-use and upgrade existing buildings, we are greener on every front.”

Global building stock will double in floor area by 2060, so it is essential that the buildings sector starts to work together to address the problem of inefficient existing building stock. There are no shortcuts to sustainability, property developers can no longer hide behind supply chain complexity nor new construction for the sake of monetary value or economic development. If the buildings industry is serious about tackling its own impact on climate change, then a new level of honesty is required within the community. We should face the need for mass-retrofitting head-on.