A Better Energy Code Is a Holiday Gift for the Planet

The people have spoken: the 2021 building energy code will be the best one yet.

In fact, the upcoming code may represent the biggest energy efficiency gains in at least a decade for constructing or renovating homes. And that is really good news for homeowners and the planet. Commercial buildings are also poised to become significantly more efficient, saving energy and money and reducing carbon pollution.

Work has been underway all year to develop the critical 2021 International Energy Conservation Code (IECC)–and this hard work has finally paid off. After making very little in efficiency gains over the past decade, the 2021 version of the building energy code is expected to be more efficient and innovative than any previous iterations of the energy code. This progress is thanks to the government officials who vote for the energy code: code officials, state and local government employees, sustainability offices, and others, who recognize the importance of efficient new buildings.

And here’s why a strong building energy code is so important: buildings are responsible for upwards of 40 percent of carbon pollution emissions. Reversing the course of climate change simply can’t happen without addressing the efficiency and carbon emissions from our buildings. Governmental officials who voted on the code know that a strong, efficient code is necessary to meet their jurisdiction’s climate-related goals and with this vote, they put the code on the path to deliver the necessary energy savings.


Building energy codes set minimum energy efficiency requirements for new and renovated residential and commercial buildings, which means buildings meeting the most updated code versions use even less energy to keep the lights on and their inhabitants comfortable. The energy codes include specifications for components like insulation, windows, ventilation, and other energy-related parts of a home or commercial building.


It’s never cheaper or easier to add more insulation or improve building systems than when the building is under construction. And in most of the country, the energy we use every day is generated by burning fossil fuels, such as gas and coal, that produce climate-harming pollutants. So if our buildings consume less energy from the start, it reduces the amount of pollution associated with heating and lighting them over their century-long lifespans. Over time, new buildings have become more efficient thanks to improved codes, but progress has been stalled over the past decade or so.

The International Energy Conservation Code is the model building energy code updated every three years through a stakeholder process involving code officials, builders, efficiency advocates, and other interested parties. Once the model code is developed, it’s then up to cities and states to adopt it. The IECC is used by more than 40 states, although not all are using the latest version. It also is recognized by the Department of Energy (DOE) and cited in federal law.


The DOE found that, taking into account the fact that states adopt the model building codes at varying rates, energy codes with modest updates over the years could save consumers $126 billion on their utility bills from 2010 to 2040. This equates to a carbon pollution reduction of 841 million metric tons, equivalent to the greenhouse gases emitted by 177 million passenger vehicles driven for one year or the carbon dioxide emissions from 245 coal power plants for one year.

How a new model code happens

We started the year with a proclamation of 2019 as “The Year of the Energy Codes”–and boy, was that a good prediction! NRDC and our allies kicked it off in January by submitting proposals to shape the 2021 energy code, in April presented residential and commercial proposals at the Committee Action Hearings in Albuquerque, and then revised and re-presented them in October at the Public Comment Hearings in Las Vegas. Local government officials came out in droves to vote for the code in late November and early December, and now we’re rounding out the year with some truly remarkable results for energy efficiency and the climate.


To be honest: The odds were stacked against those of us who love energy efficiency. The technical committee that evaluates the residential proposals is dominated by homebuilder interests, and the committee’s recommendations tend to favor keeping the code as is, by recommending disapproval on nearly all of the most innovative proposals. And that happened again this year. Overturning the committee to get a proposal passed into code requires a two-thirds majority of voters, whereas confirming a committee recommendation requires just 50 percent of votes–yet the local and state government officials voting this year overturned the committee on dozens of proposals, sending a loud and clear signal that efficiency improvements are critically important to fighting the climate crisis and here to stay. It's great that local officials participated in the International Code Council's process and made their voices heard in favor of efficiency.


Here’s a taste of what the 2021 energy code will contain:


Zero-Energy Buildings Appendix

NRDC and the New Buildings Institute collaborated on an innovative proposal to create a new, optional appendix for local code adoption that will result in residential buildings which, over the course of a year, would produce as much clean energy as they consume. This will be achieved through a mix of aggressive, yet achievable, levels of energy efficiency combined with renewable energy generation like rooftop solar panels. Many states and cities have carbon reduction and sustainability targets they must meet as part of a state law or local ordinance, and hundreds have signed onto the “We Are Still In” pledge to meet the greenhouse gas emissions reduction goals of the Paris Climate Agreement. Having a ready-made option to adopt clear code language that will require zero-energy use in new homes is critical to making them more energy efficient in a way that can be consistent across jurisdictions, easing the path for builders, code officials, and homebuyers.


Electrification and Electric Vehicles

We’re also thrilled to see that voting members adopted proposals related to ensuring buildings are ready to use or switch to electricity rather than fossil fuels for water and space heating (RE147) and ready to charge electric vehicles for both commercial and residential buildings. Electrification of buildings and vehicles–with increasingly clean electricity generated from renewable, no-emissions resources–is one of the key policy solutions for tackling climate change, and in new buildings, electrification readiness can be done at a very small incremental cost.


Flexible Residential Improvements

Residential builders will now be required to select from an additional package of efficiency improvements, focused on either enhanced building envelope, more efficient HVAC equipment performance, reduced energy use in water heating, more efficient duct thermal distribution, or improved air sealing and efficient ventilation. This mirrors the structure of a section of the commercial code, which requires additional efficiency through a package of improvements. Builders still can choose which type of improvement will work best for the home being constructed.


Lighting Efficiency and Lighting Controls

Multiple lighting-related proposals were passed, including proposals to increase lighting efficiency in homes, add lighting controls, and install multifamily exterior lighting.


Residential Water Heating and Water Use

For the first time, the residential code will consider the water heating equipment chosen for a home. While builders may still select any type of water heater, certain equipment must meet more stringent requirements. As building envelopes have gotten tighter in recent years, a greater proportion of energy costs now involves water heating. Though equipment efficiency is generally controlled by the federal government, this proposal was structured to improve efficiency while not triggering federal preemption (as states generally can’t set their own standards for equipment which has a federal efficiency), and still provide builders with lots of choices.

Furthermore, homes will also be required to have a more compact water heating system. Home designers will be encouraged to present plans that place hot water heaters and hot water outlets, such as showers and faucets, closer together, thus shortening the length of pipe in which hot water sits and cools off.  Modelling has found that over 10 percent of all hot water use is wasted due to the purging of hot water pipes until water is hot enough to use. 



We’re beyond excited that there are too many great advances in the 2021 code to summarize in one blog post. The residential code will see improvements in residential and commercial insulation and windows, commercial plug loads, energy-monitoring systems, improved efficiency of ventilation in multifamily buildings by requiring energy recovery ventilation systems, and changes to the structure of the code to make it clearer and easier to use.


Keys to success

We’re still digesting how all of these proposals will work together, but the impact over time will be significant. As we see the effects of climate change each and every day, these improvements to our new residential and commercial buildings are a necessary step toward a low-carbon, safer future.

This progress would not have happened without the huge numbers of local government voting representatives who stepped up and voted in favor of proposals to make the code more efficient. Building code officials, sustainability departments, and state and local agencies made their voices heard, and the message was clear: a strong energy code is the best way to make sure new buildings use less energy, reduce utility bills for consumers, and emit fewer emissions that contribute to the climate crisis. If you’re a voting member and you’re reading this: THANK YOU. This is YOUR code, and you are the true climate hero.

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