More than 1,000 U.S. companies, including some of the nation’s largest manufacturers, are urging Congress to preserve the 25-year-old Energy Star program to promote efficiency in home and business products.

President Donald Trump’s proposed budget would eliminate funding for Energy Star, which encourages efficiency in major appliances, office equipment, lighting and home electronics.

Companies including United Technologies (UTX), Ingersoll Rand (IR) and Staples (SPLS) call the program a model for successful collaboration between the public and private sectors.

In a letter to the Trump administration and congressional leaders, the companies say Energy Star “should be strengthened, not weakened” to encourage businesses and consumers to conserve energy.

United Technologies is the parent company of Carrier heating and cooling, Otis elevators and Pratt & Whitney engines, while Ingersoll Rand is the parent of Trane heating and cooling. Other companies signing the letter include LG Electronics USA, Panasonic Corp. of North America, Samsung Electronics America and Nest thermostats, owned by Google.