Four primary greenhouse gases contribute to climate change: Carbon Dioxide, Methane, Nitrous Oxide, and Fluorinated gases. According to EPA's 2020 overview of greenhouse gas emissions, 79% are Carbon Dioxide, 11% are Methane, 7% are Nitrous Oxide, and 3% are Fluorinated Gases.

Let's look at where Carbon Dioxide is coming from and what would be an alternative way to reduce them.

Carbon Dioxide:

Building and construction account for approximately 37% of all carbon dioxide emissions in the world. A recent EIA monthly energy review also indicated that total end-use energy consumption by the residential and commercial sector was about 21 quadrillion BTU.(1) That equals about 28% of US end-use energy consumption in 2021.

How Can The Building Sector Reduce Carbon Emissions?

There are many ways to eliminate carbon dioxide emissions in buildings. The easiest way is to reduce consumption through energy-efficient design (such as energy-saving fixtures, low-E glass or occupancy sensors, etc.) Then use onsite or off-site renewable energy to make up the energy from the utility grids.

Net Zero buildings (also called 'zero energy buildings') combine energy efficiency and renewable energy generation to consume only as much energy as can be produced onsite through renewable resources over a specific period. There are standard features in those Net Zero buildings, such as using:

Integration system
Passive systems
Thermal mass/radiant system
Ground heat sinks
Onsite energy generation

How Do Cities Help Their Buildings To Reduce Carbon Emissions?

An incremental approach to decarbonizing the buildings will not be the sole solution. Other than the recent Inflation Reduction Act, places like New York City passed a new bill- Climate Mobilization Act which set caps for various buildings to retrofit to get 40 percent of greenhouse emissions to decrease by 2030. Washington DC's Clean and Affordable Energy Act requires private residential and commercial buildings of 50,000 square feet and larger and all public buildings of 10,000 square feet and larger to annually track and report energy/ water consumption (2). In 2020, Montgomery County approved an updated local tax program for both new and existing green buildings to incentivize developers and owners to invest in deep energy efficiency and sustainability in their properties.

Additional Sustainable Credit

An entire section in LEED v4.1 is dedicated to energy saving and optimization: Energy and Atmosphere. There are a total of seven categories in LEED requirements. A project can pursue the most accumulated points from this EA category.

When talking about energy performance, ASHRAE 90.1 is the go-to guide for reference. It offers two paths for buildings to express their energy efficiency level: a Prescriptive provision and the Performance Rating Method, which uses the Performance Cost Index(PCI) as its measurement basis.

How Can We Help Our Buildings To Meet Decarbonization Goal

Calculating every bit of carbon dioxide equivalents on a daily basis is only feasible for few people. Addressing building emissions is not just a matter of net-zero policy or sustainable design; it is more about how we live, work, play, and learn in our environments. If our lifestyle and consumption habits remain the same, it will be hard for the building industry to have a profound change.

Why don't we begin with a few tiny steps? For example, increasing the walkability in our neighborhood, taking stairs than elevators when we can, using manual operation equipment, or even air-dry clothes would be suitable choices.

Notes and References:

“How much energy is consumed in U.S. buildings?”, Frequent Asked Questions/ U.S. Energy Information administration.
There are currently 1054 buildings currently tracked for greenhouse gas emission. Reference the Map of all buildings included in DC greenhouse gas emissions
Learn more about What is a Zero Energy Building with a easy understand video on energy.gov.
For readers who want to understand more about the project qualification and code implementation of the recent Inflation Reduction Act of 2022, check out "An Energy Bill Talk"/ Letter to Tiffany.