After a wait of nearly two years, the Energy Department proposed two major energy efficiency rules Thursday for new commercial refrigeration equipment and walk-in coolers and freezers.

The rules represent one of the Obama administration’s first steps to address climate change through executive authority since the president announced a climate action plan in June.

Environmentalists and some lawmakers had pressed the Energy Department to issue the proposals, one of which had been pending at the Office of Management and Budget for nearly two years.

The proposals have a significant environmental effect because of the size of the appliances involved. The first rule applies to equipment such as restaurant-size fridges or deli cases at convenience stores, while the second applies to milk display cases used in supermarkets.

Neither will apply to existing equipment, and businesses will have three years to comply with the rules once they are final.

Heather Zichal, deputy assistant to the president for energy and climate change, wrote in a blog post Thursday that energy efficiency is “one of the clearest and most cost-effective opportunities to save families money, make our businesses more competitive, and reduce greenhouse gas emissions.”

Over the next 30 years, Zichal estimated, the two rules could cut Americans’ energy costs by up to $28 billion and reduce the nation’s carbon dioxide emissions by over 350 million metric tons. Commercial refrigeration equipment will become roughly 15 percent more efficient under the proposed standard, according to the Energy Department.

“This reduction in CO2 emissions would be the equivalent of taking nearly 109 million new cars of the road for one year,” she added. “Or put another way, the energy saved from these proposed rules would be equal to the amount of electricity used by 50 million homes in a year.”

Sen. Sheldon Whitehouse (D-R.I.), who had criticized the delays, praised OMB for issuing the rules Thursday. “With Congress still paralyzed by the influence of the big carbon polluters, these are exactly the kind of actions the administration should take to fight back against climate change,” Whitehouse said.

The proposed rules will be subject to public comment for 60 days before the agency can finalize them.