Month: January 2025

By Elizabeth Willis

Buildings account for nearly 40% of the energy consumed annually in the United States, making them not only one of the largest contributors to greenhouse gas emissions but also one of the most promising sectors for meaningful improvement. Even small gains in building efficiency can have an outsized impact, driving significant emissions reductions and positioning buildings as a critical focal point for climate action. 

As cities and states across the U.S. begin implementing ambitious climate plans, Building Performance Standards (BPS) are emerging as a powerful and effective policy tool. By focusing on improving the energy efficiency of existing buildings, BPS policies fill a gap that traditional building codes—primarily aimed at new construction—fail to address. This is especially critical because most of the buildings that will be in use by 2050 have already been built. Achieving meaningful emissions reductions requires modernizing the aging building stock to meet higher energy performance standards. Building Performance Standards (BPS) help accomplish this by driving energy efficiency improvements, lowering operational costs, and reducing greenhouse gas emissions while delivering broader benefits such as improved air quality, job creation, and community health. 

In this post, we’ll delve into the fundamentals of Building Performance Standards, their importance in advancing climate goals, the challenges of implementing them, and why they hold particular promise for the Southeast, where unique hurdles intersect with urgent needs for equity-driven energy policy. 

Map by U.S. Department of Energy

What Are Building Performance Standards (BPS)? 

Building Performance Standards (BPS) are policies that require existing buildings to meet specific energy or emissions performance targets. These policies are typically adopted by municipalities or states seeking to cut energy consumption, reduce carbon emissions, and improve public health. BPS policies typically focus on large commercial and multifamily buildings, requiring owners to meet measurable benchmarks that get more stringent over time, mandating continuous improvement in the buildings’ performance.  

Unlike traditional building codes, which focus on prescriptive requirements for new construction, BPS take an outcome-based approach. Property owners are granted the flexibility to choose the strategies that work best for their buildings, whether it’s retrofitting HVAC systems, improving insulation, installing renewable energy systems, or upgrading windows. What matters is the result: improved energy performance that aligns with the jurisdiction’s climate and energy goals. 

The brilliance of BPS lies in its focus on existing buildings—a critical yet often overlooked segment of the built environment. While new buildings constructed under modern codes already achieve high efficiency levels, older structures usually lag behind. By requiring existing buildings to improve their performance, BPS ensures that the entire building stock contributes to long-term energy savings and carbon reductions. 

The Benefits of BPS 

Building Performance Standards (BPS) offer a spectrum of benefits that extend beyond energy efficiency. They drive substantial energy savings, lower greenhouse gas emissions, and enhance the functionality of existing buildings. By modernizing aging infrastructure, BPS boost property values, stimulate local construction jobs, and improve indoor living conditions, promoting better air quality, comfort, and productivity for occupants. Communities benefit from cleaner outdoor air, improved public health, and measurable progress toward climate goals. Furthermore, these standards provide state and local governments with actionable insights, increase market transparency, and strengthen tenant satisfaction by fostering sustainable and efficient building operations. 

Why Building Performance Standards Are Essential 

Buildings are at the center of the climate challenge—and the solution. Accounting for nearly 40% of energy consumption in the U.S., buildings are one of the largest contributors to greenhouse gas emissions. Yet, they also represent a massive opportunity for progress. 

Most of the buildings we rely on today will still be in use decades from now. Focusing exclusively on making new buildings energy-efficient isn’t enough to meet our climate goals. Instead, we need policies that drive retrofitting and modernization in existing structures, where the potential for energy savings is most significant. 

This is where BPS policies shine. By setting clear, measurable performance standards, they provide a structured pathway for building owners to upgrade their properties over time. Jurisdictions with ambitious climate action plans—such as Washington, D.C., and New York City—are leveraging BPS to reduce emissions and energy use across their building stock, demonstrating the potential for other cities and states to follow suit. 

Challenges to Implementing BPS in the Southeast 

The Southeastern United States faces unique challenges that make implementing BPS both more complicated and more necessary. This region, characterized by high energy consumption, aging infrastructure, and inequities in energy access, provides a vivid case for why BPS policies are needed—and what makes them challenging to implement. 

One of the primary challenges to building innovation in the Southeast is the regulatory environment . States like Tennessee and Kentucky prohibit local jurisdictions from adopting building policies that go beyond state-mandated codes. This creates a roadblock for cities like Nashville and Louisville, which have expressed interest in BPS but are unable to move forward under current laws. 

Another significant hurdle is the prevalence of historic buildings in the region. While these structures are culturally and architecturally valuable, they are often expensive and difficult to retrofit for energy efficiency. Preservation restrictions can further complicate efforts to modernize these buildings, limiting the types of upgrades that can be made. 

Perhaps the most pressing—and often overlooked—challenge in the Southeast is the region’s high energy burden and widespread energy insecurity. The Southeast has the highest proportion of households in the U.S. that spend an unsustainable percentage of their income on energy costs. This problem disproportionately affects low-income families and communities of color, many of whom struggle to afford consistent and reliable energy. 

Energy insecurity forces families to choose between paying their utility bills and meeting other basic needs like food, medicine, or rent. By reducing energy consumption and lowering energy bills, BPS policies have the potential to alleviate this burden, creating a more equitable energy future. However, historic disinvestment in underserved communities complicates this process. Many property owners in these neighborhoods lack access to the capital needed for retrofits, perpetuating a cycle of inefficiency and inequity. 

Despite these challenges, the Southeast represents an immense opportunity for BPS to make a meaningful impact—especially when policies prioritize equity and target resources to areas that need them most. 

Establishing Benchmarking as a First Step 

Implementing a full-scale BPS policy begins with benchmarking. A benchmarking policy requires building owners to measure and report their energy use, creating a comprehensive dataset that helps jurisdictions understand the energy performance of their building stock. 

Benchmarking is a foundation for future BPS policies that sheds light on the energy performance of each building in a particular jurisdiction and provides a way to compare buildings. It also raises awareness among property owners, often spurring voluntary improvements before mandatory policies are enacted. For example, Atlanta’s voluntary benchmarking policy has provided valuable insights into energy consumption patterns, though the lack of required performance targets limits its potential to drive impactful upgrades. 

Leading by Example with Public Buildings 

Many jurisdictions begin their BPS journey with government buildings, using them as a proving ground for the policy. By mandating performance standards on public facilities, cities and states can demonstrate the feasibility of retrofitting projects, leading by example and highlighting the benefits of energy upgrades. 

This “lead by example” approach generates momentum for broader public adoption and helps refine the policy before extending it to the private sector. Public buildings provide a controlled environment for testing strategies, making them ideal starting points for BPS implementation. 

Conclusion: Building a Sustainable and Equitable Future 

With its unique challenges, the Southeast represents both a significant hurdle and an unparalleled opportunity. By prioritizing energy equity and targeting resources to underserved communities, BPS policies can do more than just reduce emissions—they can improve quality of life, alleviate energy burdens, and foster long-overdue investments in historically disinvested neighborhoods. 

As cities and states across the country work to meet ambitious climate goals, BPS offers a powerful tool to ensure that progress is inclusive, impactful, and far-reaching. Building Performance Standards are more than just an energy policy—they’re a pathway to a more sustainable, equitable, and resilient future.  

By: Olivia Begalla & Amy Lovell

Building insulation is a critical component of energy-efficient design, providing resistance to heat flow to enhance the overall comfort and efficiency of a home. Proper insulation helps maintain a stable indoor temperature, reducing the need for heating in the winter and cooling in the summer. This not only improves comfort but also significantly lowers energy bills and decreases environmental impact by reducing energy consumption.  

There are two primary types of insulation installations: continuous insulation and cavity insulation. Continuous insulation spans across structures without interruptions and is commonly installed on the exterior of the home. In contrast, cavity insulation is located within wall cavities, fitting between framing members. Insulation materials include fiberglass, cellulose, foam, and natural fibers, each offering unique benefits. These may be applied in rigid sheets, rolled from batts, blown as loose material, or sprayed in an expanding foam.  The U.S. Department of Energy offers a comprehensive guide to insulation materials, helping homeowners and builders choose the best options for their needs.  

Heating and Cooling Homes  

An important goal for a home is to maintain an indoor temperature that is safe and comfortable, and at the same time, affordable. There are different challenges to maintaining comfortable temperatures in winter and summer, but the principles are the same. Heat will flow from hot to cold, and the flow is faster when the temperature differences are the highest. 

  

On a spring day when it is 64° F outside and the house is 68° F inside, there is only a 4° difference, and the heat flow is minimal.   

However, on a colder day when it is 35° F outside, the temperature difference increases to 33°. This larger difference causes the house to lose its heat at a more rapid rate, requiring greater energy input into the home to maintain the same indoor temperature. 

Degree days are a measure of how cold (heating) or how hot (cooling) a location is relative to a standard indoor temperature. They allow us to compare one location to another and also to compare one year to another at the same location. Importantly, we must consider weather when we analyze impacts of energy efficiency upgrades, such as adding insulation so that we are not confusing our results with having, for example, an unusually warm winter. 

In the Southeast, our intuition might tell us that our focus should be primarily on cooling, but the data tell a different story for much of our region. Figure 1 shows that heating degree days far outnumber cooling degree days in the Southeast*, because both the temperature differences are larger, and there are more days each year that require heating.   

Figure 1: Heating and Cooling Degree Days in the Southeast* 

*Southeastern states include the Atlantic coast from Florida to Virginia, plus Alabama and Tennessee  

Data Source:  NOAA National Centers for Environmental Information, 

Building Energy Codes and R-Values 

The goal of insulation is to resist heat flow, and the ability to resist is measured in the R-value of the insulation that is installed.  R-values are always measured for an assembly, so insulation installation quality is critical to performance. Higher R-values do a better job of slowing down the heat flow, leaving the home occupant more comfortable, and with a lower energy bill.  Most insulation is some type of fluffy, low-density material that captures pockets of air and keeps those pockets of air from flowing easily to the spaces beyond.  Sometimes, these are paired with a radiant barrier, which is usually a shiny material that reflects the heat back where it came from. 

Building energy codes specify minimum R-values for insulation based on climate zones and for different parts of the home. Across the Southeast, many states currently enforce energy codes that fall below the most recent, 2021 International Energy Conservation Code (IECC). To explore current insulation requirements for each state, visit the Insulation Institute’s Codes and Standards Page.  

However, homes in the Southeast can still be built to meet or exceed the 2021 IECC standards. These standards reflect modern advancements in technology, offering greater cost-effectiveness and resilience for today’s needs. The table below outlines the insulation requirements specified in the 2021 IECC for Southeast Climate Zones.  

Table 1: IECC Insulation Requirements 

Climate Zone	Uninsulated Attic	3-4 Inches of Existing Attic Insulation	Uninsulated Floor	Uninsulated Wood-Frame Wall	Insulated Wood Frame Wall
1	R30-R49	R19-R38	R13	R13 or R0 + R10 CI*	N/A
2	R49-R60	R38-R49	R13	R13 or R0 + R10 CI	N/A
3	R49-R60	R38-R49	R19	R20 or R13 + R5 CI or R0 + R15 CI	Add R5 CI
4 except Marine	R60	R49	R19	R20 + R5 CI or R13 + R10 CI or R0 + R15 CI	Add R10 CI
4 Marine and 5	R60	R49	R30	R20 + R5 CI or R13 + R10 CI or R0 + R15 CI	Add R10 CI

Though summer heat can be intense, winter conditions have a stronger influence on the insulation recommendations, largely because of the higher heating degree days illustrated in Figure 1. Within the building, since most insulation materials are low in density, they require a lot of space to act effectively.  

For most climate zones in the Southeast, attic insulation of up to R-60 and wall insulation up to R-20, or an equivalent in continuous insulation, is specified in the 2021 International Energy Conservation Code (IECC), as shown in Table 1. Continuous insulation can be installed at the time of construction or during renovations. A typical attic design permits the installation of many inches of thick insulation to protect the living spaces below from heat loss, while on the other hand, the wall thickness may limit how much cavity insulation can be installed. Walls constructed with 2×4 wood studs, for example, can have R-15 insulation in the wall cavities. The Insulation Institute estimates that compressing thicker insulation into thinner wall gaps reduces its effective R-value.   

The ground has a higher density and heats and cools more slowly than the surrounding air, so basements and foundations that are below ground will need less insulation to protect the home from underneath.  Raised homes or other types of floors with direct exposure to air flow require greater R-values, particularly in colder climate zones. 

Insulation batting is manufactured in rolls, usually of glass fibers, with thickness according to the expected depth of the construction materials.  Loose insulation of cellulose or fiberglass can be blown into attics to a depth that produces the desired R-value. Over time, the insulation may compress or be damaged by water or pests, which can reduce its effectiveness. In addition, recommendations are updated periodically as knowledge and technology improve, so many existing homes may need attention to the level of insulation.  2024 research sponsored by the North American Insulation Manufacturers Association (NAIMA) reveals that 89% of US single-family homes are under-insulated! Is yours one of them? ENERGY STAR offers helpful guidance on how to assess your insulation levels and understand the recommended R-values for retrofitting.  

Retrofitting your home with proper insulation can significantly improve comfort and reduce costs. Table 2 below illustrates the estimated utility bill savings from sealing and insulating homes in different climate zones across the South, demonstrating how such upgrades can lead to meaningful reductions in heating and cooling energy use. 

Table 2: Estimated Heating and Cooling Savings from Home Sealing and Insulating 

Climate Zone	Estimated Annual Utility Bill Savings (%)
4	17%
3	14%
2	9%
1	7%

Figure 2: SEEA Research Associate Amy Lovell captured this thermal infrared photo in her home, where she discovered a panel of insulation had fallen down into a kneewall attic. Where the panel was missing, more heat could transfer between indoors and outdoors, with a visible thermal effect. 

Figure 3: This thermal infrared photo illustrates that the insulation captured in the wall was likely damaged when the roof leaked in the past.  Compared to adjacent sections of the wall, the insulation is still working somewhat, but not as effectively as in areas that were not degraded. The windows in this photo also appear in blue and purple colors, indicating they are also colder due to increased heat loss across the glass.