Net-zero homes are designed and built to produce as much renewable energy as they consume annually. They contribute to sustainability and help combat climate change. However, their total carbon footprints include operational and embodied carbon, and industry professionals must find ways to mitigate both to create a truly net-zero structure.

Operational vs. Embodied Carbon

Operation and embodied carbon are aspects of a structure’s emissions that make up its total carbon footprint. To reach net zero, residential houses and other properties must consider both types of carbon emissions. Here is what sets them apart:

• Operational carbon refers to the structure’s everyday power consumption and resulting carbon emissions. Heating, cooling and lighting all require electricity.
• Embodied carbon is the CO2 associated with the materials and construction processes while the home was being built.

Why Embodied Carbon Is Gaining Attention

In 2022, the residential and commercial sector accounted for 13% of operational carbon emissions in the U.S. Energy-efficient measures have been widely implemented to reduce operational carbon, which can reduce energy bills and improve indoor air quality. Many homeowners currently utilize smart home technology, like LED lights, electric heating systems and other eco-friendly functions.

However, embodied carbon accounts for an average of 50% of a building’s carbon, even for newer, more efficient buildings. Approximately 10% of energy-related CO2 emissions are attributable to buildings’ embodied emissions globally. Many standards and regulations are now focusing on mitigating embodied carbon’s rising share in total emissions.

Measuring the Full Carbon Footprint

Operational carbon is measured based on a house’s energy consumption and waste management. To measure embodied carbon, one must examine the materials and methods used to construct the house and their associated emissions.

A life cycle assessment evaluates a building’s full carbon footprint, encompassing operations and embodied carbon. This comprehensive approach considers the potential environmental impacts over the course of a house’s entire lifespan, from material extraction to end-of-life disposal or recycling.

How Green Homes Reduce Carbon

Net-zero homes are designed to minimize power consumption and generate renewable energy, leading to long-term savings and increased property values. The following are some methods and case studies for reducing embodied and operational carbon.

1. Adopting Sustainable Construction

Proactive planning to reduce embodied carbon starts with the initial design and blueprints. Carefully select low-carbon materials, such as recycled steel or timber. These can decrease embodied carbon by 40% compared to conventional building materials. Low-carbon materials are also more efficient to move to the site, resulting in a 39% lower transportation carbon footprint.

Prefabrication and modular construction can also significantly reduce embodied carbon. Constructing parts of a home off-site allows for better resource management and shorter construction timelines. They can also be designed for easy disassembly and reuse. In London, two residential developments utilizing volumetric modular systems achieved 45% and 41% less embodied carbon than conventional methods.

Green construction experts can further prevent embodied carbon when they factor in materials and prefabrication. A study found that a mid-rise housing design combining mass timber and modular components can reduce embodied carbon by 65%, along with 10% cost and 15% time reductions.

2. Implementing Green Technology

There are ways to maintain low operational carbon emissions after a house is built. Homeowners can consider using smart home technology, such as thermostats that automatically adjust the temperature and lights with timers to turn off after a set amount of time.  Smart appliances can decrease utility bills up to 22%, making them a great choice for wallets and the planet.

Renewable energy integration can help lower emissions. This includes using alternative electricity sources — solar panels, wind turbines or geothermal systems — rather than fossil fuels. These methods are becoming increasingly accessible, with renewables generating almost a third of the world’s electricity in 2024.

3. Meeting Standards For Energy Efficiency

Energy standards and regulations evolve to improve efficiency. Adhering to them is essential to achieving and maintaining net-zero performance. Here are several examples impacting residential homeowners and renters:

• The Energy Star Most Efficient addresses appliance choices, from lighting to refrigerators. This widely recognized, voluntary program helps homeowners and renters identify energy-efficient products.
• The Seasonal Energy Efficiency Ratio 2 is the updated rating system for HVAC equipment. Higher-rated systems use less electricity for heating and cooling, reducing both carbon emissions and utility bills without sacrificing comfort.
• The Home Energy Rating System Index and DOE Home Energy Score calculate a house’s energy performance, which can be used for code compliance and green building programs. Lower scores indicate higher efficiency.
• The International Energy Conservation Code sets minimum energy-efficiency requirements for new and renovated residential buildings. This model is expected to help structures avoid 841 million metric tons of emissions by 2040.

Managing Embodied and Operational Carbon

A residential property’s total carbon footprint is determined by its operations and embodied carbon emissions throughout its lifespan. Builders and homeowners can make more efficient houses and work toward a net-zero footprint in many ways.

Checkout the GreenHome Institute Emboddied Carbon CEU Webinar Playlist to learn more