Eileen McGurty - Climatebase
May 12, 2026
A high performance building is a more technical framing of what most people call a green building. It is a building that reduces greenhouse gas emissions and minimizes its broader environmental footprint across both the way it's built and the way it's run.
Four characteristics define one. It is energy efficient. It offers occupant comfort, which includes indoor air quality and other comfort factors. It maintains good indoor air quality. And it is durable. Buildings that meet those criteria tend to cost more upfront and less over time. Once built, they are cheaper to operate, and the people inside them generally report a better quality of life.
Takeaway Co-benefits matter. A high performance building is not only a climate intervention. The lower operating costs and improved daily experience for occupants are often what makes the case stick with developers and tenants.
Buildings and infrastructure account for roughly 40% of global carbon emissions. That share splits into two distinct sources. Operations of buildings, mostly the energy used to heat, cool, and run them, accounts for about 29%. Embodied carbon accounts for the remaining 11%.
Embodied carbon is the carbon emitted to create everything that goes into the built environment. That includes the building itself and the roads, bridges, and tunnels around it. Foundations, beams, and columns hold the most embodied carbon, which is why concrete and steel dominate the conversation. As operational emissions fall over time, embodied carbon will make up a larger share of the total for any new building.
Takeaway Both halves of the 40% need attention. Cleaning up operations matters, but the carbon already baked into a building before anyone moves in is a problem you can't fix later.
Three strategies bring embodied carbon down: reuse existing buildings, use materials more efficiently, and begin using low-carbon materials.
Building reuse is the most powerful of the three. The lowest carbon building is the one that doesn't need to be built. Reusing an existing structure can cut embodied carbon by 50% to 75% compared to new construction, because the foundation and structural elements where most of the embodied carbon lives are already there.
Material efficiency comes down to using less stuff. That means designing adaptable spaces that can shift between uses, favoring prefabricated materials that are built off-site more efficiently than on-site, optimizing the size of the building, and committing to minimalist design. Reusing materials also belongs here, and it ties directly to designing for disassembly. A building that can be taken apart, rather than torn down with a wrecking ball, retains the value of its materials.
Low-carbon materials are the third lever. Hempcrete is one example. It is made by mixing the inner woody core of hemp with lime and is mainly used for walls and insulation. It is earthquake resistant. A study from The New School compared a traditional wall to a hempcrete one and found the traditional wall produced about 34.7 kilograms of carbon per kilogram of materials, while the hempcrete version came in at 4.6.
Concrete is the single largest source of embodied carbon. The manufacture, transport, and use of concrete account for about 7% to 8% of global emissions. Most of that comes from clinker, the material produced by heating raw inputs in very high temperature kilns. Clinker becomes cement, and cement becomes concrete. Roughly 40% of the carbon in this chain comes from the heat itself.
Several paths exist for cleaner cement. One substitutes other materials for some of the clinker without losing strength. Another startup is trying to use algae to get the structural performance concrete provides. The University of Cambridge has built an electric kiln that can reach the temperatures needed and is approaching scale. Other estimates suggest low carbon cement could reduce emissions by about 40%, or roughly 500 megatons of CO2 per year by 2030, and could represent a quarter of global cement use by 2050. CO2-sequestering concrete and calcium carbonate-based binders each have the potential to reduce around 2 gigatons of CO2.
Steel has the same problem in a different form. Blast furnaces need fossil fuels to reach the temperatures required. Hydrogen-based and electric arc furnace approaches are both being pursued. Scaling green hydrogen is still a work in progress, but British Steel has produced electric arc furnace steel that meets the structural criteria, and it's about ready to scale. British Steel also announced a £1.25 billion investment in 2023 to replace two of its blast furnaces.
Takeaway The carbon math of a new building is mostly written by concrete and steel. The fastest way to cut embodied carbon today is to reuse what's already standing. The medium-term play is to swap the worst materials for cleaner versions of the same thing.
Heating, ventilation, and air conditioning is the largest component of energy use in building operations, especially in commercial buildings. Residential percentages differ, but the pattern holds. If you want to cut operational emissions, HVAC is where to focus.
Passive building design sets the foundation. A passive approach uses continuous insulation without thermal bridging, an extremely airtight envelope, high-performance windows and doors, and a balanced ventilation system that recovers heat and moisture. Several jurisdictions now require it.
Three emerging HVAC technologies do most of the work. The first is the electric heat pump. A typical air source heat pump pulls heat from outdoor air, runs it through a refrigerant that gets compressed to raise the temperature, and pushes the warm air into the home. In summer the cycle reverses, absorbing warm air from inside and moving it out. Heat pumps can be about 300% more efficient than a furnace. They lose efficiency in very cold climates, which is why Montana homeowners often need a backup furnace through the deepest winter weeks. Policy incentives have driven adoption across Europe, China, Japan, and the US, and global sales have been climbing.
Geothermal heating and cooling works on a similar principle but uses the constant temperature underground as the heat source or sink. It is very efficient, producing about 85% fewer emissions than a gas furnace and 90% fewer than propane, and it uses roughly 4 times less electricity on the coldest days than an air-source heat pump. The upfront cost is steep because of the drilling and infrastructure involved. Europe has the strongest incentive structure. China has gone further and is installing district geothermal systems, with multiple boreholes dug under shared infrastructure and connected to nearby buildings. As one CleanTech writer put it, "The Western discourse may still be stuck debating gas vs heat pumps at a single-home level, but China has moved on to 'how do we dig 400 boreholes under a high school football field and connect them to every building in a ten-block radius?'".
Active thermal solar is the third. It uses solar collectors to heat water rather than to generate electricity, and the hot water is then pumped into the building for hot water or space heating. It works well in places that don't get very cold, and it's relatively inexpensive, so it has potential outside the wealthy industrialized world. Installations are growing globally.
Electrifying everything in a building, from heating to hot water, can deliver large carbon savings and meaningful operational cost reductions. Rewiring America estimates household savings of around $2,500 in its more optimistic scenario.
Takeaway HVAC is the single biggest operational lever. Heat pumps and geothermal are the technologies most ready to scale, with active thermal solar filling in where the climate cooperates and the budget doesn't stretch to drilling.
Policy nudges high performance buildings through a mix of incentives and regulations. Incentives make it more profitable for developers and consumers to build or buy better. Regulations set minimum standards everyone has to meet.
Density bonuses are a local incentive. If a developer agrees to build a high performance building, the jurisdiction grants an exemption from the usual zoning limits, allowing more units per parcel. That changes the return on investment math significantly. Expedited permitting works the same way. Every day a project sits in permit review can cost a developer real money, so faster review is a powerful incentive. Tax credits apply at multiple levels and to both developers and consumers, and a range of technical assistance programs help close information and capacity gaps.
Building codes are the main regulation. They shape the urban landscape even when they sound abstract. Modern codes are roughly 30% more energy efficient than codes from a decade ago. About 103 countries use the International Code Council (ICC) model, and most local jurisdictions adopt it wholesale because they don't have the in-house expertise to write their own. The ICC's 2025 update proposed electrification requirements for new buildings, including readiness for charging facilities, but the requirement was pulled at the last minute under pressure from the building and developer industries. California passed the same electrification rule on its own.
Takeaway Incentives work because they line up with what developers already care about. Regulations work when jurisdictions are willing to write the rules and stand behind them.
Third-party certifications give a building a way to prove it's doing what its developer says it's doing. LEED, BREEAM, and the Living Building Challenge are the three main systems.
LEED is run by the US Green Building Council and is the largest certification in the US, with more than 100,000 commercial buildings certified. It uses a points-based system across categories like sustainable sites, water efficiency, energy, materials and indoor environmental quality, and location and transport. Buildings earn silver, gold, or platinum ratings depending on their point total, and the standard covers buildings, interiors, operations and maintenance, neighborhoods, healthcare, schools, and warehouses.
BREEAM, the Building Research Establishment Environmental Assessment Method, uses a similar points-based approach across 12 categories. About 2.9 million buildings are registered for BREEAM certification across 103 countries. UNESCO's World Headquarters in Paris is one example.
Both systems face real challenges. The criteria weights raise questions. Should a point for energy use count the same as a point for embodied carbon? Assessment is based on design rather than how the building actually performs, so a building can earn a high rating on paper and underperform in practice. Both groups have plans to add performance-based outcomes, but the change hasn't happened yet. The point structures and requirements also keep evolving, which means a platinum LEED building from 2010 isn't directly comparable to a platinum LEED building from 2026.
The Living Building Challenge attempts to address the design-versus-performance gap. Its criteria are performance-based and certification is assessed after 12 months of actual operation. The PAE Building in Portland, Oregon is one certified example. It generates 113% of its energy use through onsite and offsite renewables. It collects, treats, and reuses 100% of its water onsite, with an underground cistern and compostable toilets. Operable windows ventilate or cool 70% of the building's perimeter spaces. The structural material is Pacific Northwest cross-laminated timber certified by the Forest Stewardship Council.
Takeaway Points-based certifications have moved the market, but they grade design more than results. Performance-based standards like the Living Building Challenge are closer to what the next generation of certifications will need to look like.
What does embodied carbon mean?
Embodied carbon is the carbon emitted to produce, transport, and install the materials that go into a building. A slab of concrete carries the emissions from extracting the raw materials, processing them, and getting the slab to the construction site. Those emissions are embodied in the material itself.
What refrigerants are used in modern heat pumps, and are they a leak risk?
Heat pumps built before around 2020 mostly used hydrofluorocarbons, which have very high global warming potential. Most jurisdictions have since regulated those out, and current refrigerants have lower global warming potential. The systems are designed to be closed loops, but leaks do happen, so the refrigerants still matter even though the situation has improved.
What are building codes?
Building codes are local, provincial, or state laws that set the rules for how a building has to be built. They cover materials, the number of windows and egresses, setbacks from the street, and a long list of other specifications. They shape the urban landscape even though they sound technical.
Can building materials like concrete and steel be recycled when a building comes down?
Not easily. Concrete loses strength if you try to break it down and reform it. Steel can be recycled, and most of it is, because new steel is expensive to make. The bigger opportunity is design for disassembly. A building put together so it can be taken apart cleanly keeps the value of its wood, metal, and other recoverable materials. Companies do this work today, salvaging wood and metal from buildings to be used elsewhere.
Embodied carbon — The carbon emitted across the extraction, manufacturing, transportation, and installation of the materials and components that make up a building. source
Operational carbon — The carbon emitted from the energy used to heat, cool, light, and run a building over its lifetime. source
Clinker — The high-temperature output of cement kilns. It is the intermediate material that becomes cement, which becomes concrete, and is responsible for roughly 40% of concrete's carbon emissions. source
Hempcrete — A wall and insulation material made from the inner woody core of hemp mixed with lime. Earthquake resistant but not structurally strong enough to replace concrete.
Heat pump — An HVAC system that moves heat between indoor and outdoor air using a refrigerant cycle. Can heat or cool depending on the direction of flow, and can be about 300% more efficient than a furnace. source
Geothermal heating and cooling — A system that uses the constant temperature underground as a heat source in winter and a heat sink in summer. Roughly 85% fewer emissions than a gas furnace and 4x less electricity than an air-source heat pump on the coldest days. source
Active thermal solar — Solar collectors that heat water directly rather than generating electricity. The hot water provides domestic hot water or space heating. source
Passive building design — A design approach using continuous insulation, an airtight envelope, high-performance windows and doors, and heat and moisture recovery ventilation. source
ICC — The International Code Council, whose model code is used by about 103 countries as the basis for local building codes.
LEED — Leadership in Energy and Environmental Design, the US Green Building Council's points-based certification, used by more than 100,000 commercial buildings.
BREEAM — Building Research Establishment Environmental Assessment Method, a points-based certification across 12 categories with about 2.9 million buildings registered in 103 countries.
Living Building Challenge — A performance-based certification assessed after 12 months of operation, focused on actual building performance rather than design intent. source
Defensible space — The cleared zone around a structure in a wildfire-prone area, designed to remove fuel so the building itself can be defended.
US Green Building Council - LEED — Home of LEED certification, points criteria, and the rated building registry.
BREEAM — Building Research Establishment certification system used across 103 countries.
Living Building Challenge — Performance-based green building certification from the International Living Future Institute.
PAE Living Building, Portland — Certified example referenced in the lecture.
IEA Heat Pumps — Global heat pump tracking and sales data.
International Code Council — Source of the model code used by most jurisdictions.
Phius — North American passive building standard and certification body.