Does energy efficiency still save money? We used digital twins to test it.
For decades, energy efficiency (EE) programs have delivered maximum energy savings while also helping customers save money on their energy bills without sacrificing the comfort of their homes. Utilities also benefit significantly from well-designed EE programs through improved customer satisfaction, enhanced grid reliability, and potentially deferred system upgrade costs. Most experts can agree that EE programs help customers reduce energy usage and can help offset rapidly rising energy costs. But how do these energy efficient upgrades help customers during periods of unseasonable weather?
We wanted to know, so we leveraged digital twins to compare energy usage of utility customers in Maryland who participated in EE programs versus customers who did not participate. While all Marylanders experienced an increase in their electricity bills last winter, those who participated in energy efficiency programs saw an 18%-32% smaller increase compared to non-participants. This demonstrates how these programs help mitigate rising energy costs across all fuel types.
Most common energy efficiency program tactics
Traditionally, U.S. utilities have seen demand peaks during the sweltering summer months, driven by high use rates of air conditioning. But with changes in weather, winter peaks are poised to rival—or even surpass—those of summer. The bottom line is that energy conservation makes sense year-round.
In December 2024 and January 2025, Marylanders experienced higher than usual bills due to colder than usual temperatures and heavy snow. The Maryland Climate Bulletin for Winter 2023-24 reported that the seasonal mean temperatures were between 33°F and 43°F. In contrast, the previous winter (2022-2023) had significantly milder temperatures, with January 2023 averaging 43.9°F and February 2023 averaging 44.7°F.
We wanted to analyze the impact of various measures that are commonly implemented in homes participating in EE programs. For example, proper insulation is one of the most significant steps to improving energy efficiency. U.S. DOE estimates that the average homeowner can save up to 20% on their heating and cooling costs by adding insulation to attics, floors, crawl spaces, etc.
Cold weather impacts on Maryland homes
To understand how Maryland customers fared during the cold weather of early 2025, we leveraged Sightline, ICF’s cutting-edge AI and cloud-based data analytics engine, which uses high-interval actual energy usage data. We simulated a digital twin model of a representative home in Maryland to evaluate the impact of weather changes on energy bills during the winter months. Then we simulated two versions of the energy model: one representing an EE non-participating home and the other representing an EE participating home.
We ran our energy model against weather files capturing the different outdoor temperature profiles of the last and current winters. The results below show the impact of the weather during the months of December and January on the total energy bill for five types of home heating:
- Heat pumps
- Electric resistance
- Natural gas
- Fuel oil
- Propane
Figure 4 shows the average reduction in energy bill increases for participants by fuel type, illustrating that EE program participation lowered bills across all home heating methods.
Despite the colder-than-usual temperatures and heavy snow during the winter months of December 2024 and January 2025, our analysis shows conclusively that Maryland homes participating in EE programs experienced lower bill increases compared to non-participating homes. This was evident across various types of heating systems, including heat pump, electric resistance, natural gas, fuel oil, and propane heated homes. The implementation of measures such as improved insulation and more efficient heating systems contributed to these savings. This demonstrates the value of energy efficiency initiatives in reducing costs and enhancing comfort, even in challenging weather conditions.
As energy costs fluctuate, EE remains a powerful tool for helping customers manage their bills, reducing consumption, and improving home comfort—regardless of fuel type or weather patterns.