A general view of Veer Towers in front of the Aria Resort & Casino in Las Vegas. The center is said to be one of the world’s largest projects built with the Leadership in Energy & Environmental Design (LEED) Gold-certified Green Building Rating System. (Ethan Miller/Getty Images for CityCenter)

This story has been updated.

A preliminary budget proposed by the Trump administration has targeted federal environmental programs left and right for elimination — and counted on the hit list are several popular energy efficiency programs, including the Environmental Protection Agency’s Energy Star Program and the Energy Department’s Weatherization Assistance Program. Cutting these money-saving programs could be a major loss for consumers, experts have warned — but also for the climate.

But even as this is happening, new research published Monday suggests that such programs for improving energy efficiency — some of which could disappear under the Trump administration’s proposed budget — have the potential to make a big dent in our greenhouse gas output.

A new study, out Monday in the journal Nature Energy, finds that “green” buildings in Los Angeles alone are avoiding about 145,000 metric tons in carbon dioxide equivalents each year. And there’s hope that efficiency programs in other cities may performing similarly well.

“What we are doing has not been done before, just because there was no access to data of such quality and such coverage,” said study co-author Magali Delmas, a professor at the University of California at Los Angeles’s Institute of the Environment. Energy consumption data is typically private, she explained, which makes it difficult to compare the performance of buildings that participate in energy-saving programs with those that don’t.

But thanks to a partnership program at UCLA, Delmas and co-author Omar Isaac Asensio were able to access energy data from buildings throughout Los Angeles and use it to evaluate the performance of three separate energy efficiency programs: the federal Energy Department’s Better Buildings Challenge, the federal Environmental Protection Agency’s Energy Star certification program (which would be eliminated under the preliminary federal budget), and the private U.S. Green Building Council’s Leadership in Energy and Environmental Design, or LEED, program. Energy Star and LEED certification are awarded to buildings that meet certain performance standards, while the Better Buildings Challenge provides energy audits and public recognition for building owners that commit to reducing their energy consumption by 20 percent over the course of 10 years.

For the new study, Delmas and Asensio analyzed data on the energy use of 178,777 commercial buildings in Los Angeles from the years 2005 to 2012. They used a special algorithm to match buildings participating in an efficiency program with nonparticipating, but otherwise similar, buildings to make more accurate comparisons of energy performance.

And their findings suggest that the efficiency programs do have an impact, at least in Los Angeles. Buildings participating in the Better Buildings Challenge used 18.69 percent less energy than nonparticipants, while Energy Star and LEED-certified buildings used 19.31 and 29.99 percent less energy, respectively. In total, participating buildings — which occupied a total of 125.9 million square feet of floor space — saved 210.2 million kilowatt-hours of energy, which translates into 145,000 metric tons, or nearly 320 million pounds, of avoided carbon emissions. (This also surely made the buildings cheaper to operate and maintain.)

However, the researchers point out that these savings mainly apply to large-sized buildings, not medium or small ones. According to Delmas, it’s often easier for building owners to justify the upfront costs of making efficiency upgrades in larger buildings, where the payoffs for the owners — in rent premiums or increased property value, for instance — are likely to be larger.

Despite these promising results, the new paper does have its shortcomings, according to Margaret Walls of environmental nonprofit research group Resources for the Future, who was not involved with the research. The major issue with this type of study is that participation in the energy efficiency programs is voluntary, meaning there may be an inherent bias associated with the people who choose to sign up for them.

“The gold standard for identifying a true treatment effect from a policy is a randomized control trial; an untenable approach here because participation in the programs is not randomly assigned,” Walls wrote in a commentary on the new paper, also published Monday in Nature Energy.

This presents a problem when evaluating the effectiveness of an energy efficiency program because it means we can’t necessarily assume that the program is what caused a building owner to make an investment in efficiency upgrades, noted energy economics expert Catherine Wolfram of the University of California at Berkeley, who was also not involved with the new study.

“Imagine that some building owners are concerned about the environment and others aren’t,” she said in an emailed comment to The Washington Post. “The ones that are concerned about the environment will make energy efficiency investments in their buildings and they will also probably be more likely to participate in the voluntary programs.”

But this doesn’t mean the existence of the programs is what motivated them to make the upgrades, she added. In fact, in some cases, environmentally conscious building owners might make energy efficiency investments of their own accord and then afterward enroll in programs like Energy Star out of a simple desire to receive recognition for their efforts.

So the study can’t necessarily make any definitive conclusions about whether these programs are actually causing, or motivating, the savings the researchers have observed. But it does indicate that building owners who make efficiency upgrades and are enrolled in a program — whatever the reason — are contributing to substantial reductions in greenhouse gas emissions.  

And according to Walls, the researchers in this case have taken the next best possible approach with their strategy of comparing similar building types, which she argues can reduce — although likely not eliminate — the bias that results from voluntary participation in the efficiency programs. “As such, although the richness of the data and the careful matching procedures give the results merit, the magnitudes of the effects should be treated cautiously,” she wrote in her commentary, but added that the researchers “have shed critical light on the achievements of voluntary energy labeling programs for this sector.”

One question that remains is how more people — particularly those who own smaller-sized buildings — might be incentivized to start making energy efficiency investments. Simply providing better information about the long-term benefits of energy efficiency programs may help to sway some building owners, Delmas suggested.

She added that mandatory disclosure laws, which would make energy consumption data publicly available, could also help building owners to benchmark their energy use compared to other similar buildings. Nearly two dozen cities in the United States have already begun developing such disclosure programs, Walls noted in her commentary.

And while the new study can only speak for Los Angeles, Delmas noted that there’s hope that efficiency programs in other parts of the country are also paying off. Referring to a database of energy use housed by Lawrence Berkeley National Laboratory, the researchers found that the energy use intensity patterns of commercial buildings in Los Angeles are similar to those found in other U.S. cities. There are plenty of other factors that could affect the impact of energy efficiency investments in different locations, including differences in climate, the economy and market conditions, but the researchers are hopeful that green buildings in other places are seeing real savings as well.

“It might be that Los Angeles is better advanced in terms of the number of green buildings, but I think it’s indicative of what we can find in the next couple of years,” Delmas said.