Savings hidden in the code: The limits of energy code as a baseline

January 26, 2022 by Jeannette LeZaks and Scott Pigg

What's a simple climate measure that could save 80 million kWh and over 3 million therms without any new regulations? If you could find one, you'd feel like you’d cracked some sort of code. As it turns out, that's roughly how much the state of Minnesota could save if all the underperforming elements of commercial buildings were simply to meet the requirements for existing energy efficiency building codes. For building owners, that could save $10,000,000. For the state, it could simplify the path to climate action from widespread energy savings.

Commercial buildings could save 78 million kWh and 3.3 million therms annually if all the underperforming elements of commercial buildings met the 2015 Minnesota Energy Code.

In a pair of market characterization studies we conducted for the Minnesota Department of Commerce, we surveyed residential and commercial buildings to identify opportunities for energy savings associated with new and renovated properties.

These studies were not just about compliance; we also sought to quantify the lost energy cost savings relative to prescriptive energy code. Through modeling and estimates, we can determine the energy savings hidden in the current code to see the opportunities lurking in plain sight. 

Lost energy savings in commercial buildings

As seen in our study, all the underperforming elements of buildings were to meet the 2015 Minnesota Energy Code, the commercial building sector could see annual savings of approximately 78 million kWh and 3.3 million therms. That clearly represents a big opportunity, but a commercial building has lots of nooks and crannies. Where do we start to shine the flashlight to identify the lost savings?

Even if a commercial building complies with code overall, not all its elements meet the actual code requirements. Commercial buildings often meet code requirements in equipment, such as HVAC systems and envelope elements. Where buildings often don’t meet code is in their controls and configuration elements—the thermostats and lighting controls that govern the up-to-code mechanicals. 

However, codes for controls and configuration are among the toughest to enforce. Among our recommendations below, we suggest building owners and designers adopt advanced controls strategies and consider controls from the outset of design.

Slipstream has recently embarked on a new codes study (with partner Institute for Market Transformation) to assess the most complex elements of the energy code, such as advanced HVAC control sequences. We hope to be able to inform how these complex elements might affect future codes as well as code compliance support efforts.

What about residential buildings?

In residential buildings, we see the inverse: many new single-family homes in Minnesota are currently being built above prescriptive energy code, especially when it comes to windows and air leakage. If all homes were built precisely to code—no more, no less—then energy costs for the average new home would be about 4 percent more than under current construction practices.

Where codes lag market practices

In many cases—especially in commercial buildings—we found several elements that commonly go beyond prescriptive energy code requirements. This suggests that some codes may already be lagging market practices.

Building elements that commonly go beyond prescriptive code:

  • Mass wall insulation
  • Interior and exterior lighting power
  • HVAC equipment efficiency
  • Energy recovery type and effectiveness
  • Gas water heater efficiency
  • Gas space-heating boiler efficiency

While these findings present less of an opportunity to identify lost savings, it does serve as a reminder that builders and designers are sometimes ahead of the curve of current baselines. Program managers can support builders and designers with the tools to squeeze even greater energy savings from existing codes.


In the residential sector, utility programs should consider recalibrating new-construction baselines to match current construction practices—then add incentives to inspire builders to achieve even more efficiency.

As for commercial buildings, our research outlined several recommendations to Minnesota and other states to reach the full potential of the energy code, including:

  • Offering a menu of support options for code officials
  • Developing a shared set of energy code resources
  • Leveraging existing new construction programs

In addition, we can suggest a few opportunities to squeeze additional savings from the current energy code without any new regulations:

Promote high-impact prescriptive strategies that can achieve higher energy savings than current prescriptive baselines. For example, buildings could recoup a lot of lost savings by optimizing controls and configuration elements with advanced control strategies such as integrated lighting controls.

Promote energy modeling to encourage non-regulated design decisions. New buildings could achieve greater energy savings by adopting early design analysis of non-regulated elements, such as window placement and HVAC system type. Slipstream can help with energy analysis tools, including a climate model toolkit to assist with energy modeling in regions beyond Minnesota.

Watch our Webinars

For a more in-depth look at the methodology, specific findings, and detailed recommendations of each study, view the webinars we presented with representatives of the Minnesota Department of Commerce.