This paper presents estimates of the key impacts of U.S. national energy and water conservation standards adopted from 1987 through 2024. The standards for consumer products, commercial and industrial equipment, lighting products, and plumbing products include those set by legislation as well as standards adopted by the Department of Energy (DOE) through rulemaking. In 2024 alone, these standards are estimated to have saved an estimated 6.0 quads of primary energy, which is equivalent to 6.5% of total U.S. energy consumption, and 1.7 trillion gallons of water, which is equivalent to approximately 12% of the annual water withdrawals for public supply in the U.S in 2015. The estimated reduction in CO2 emissions associated with the standards in 2024 was 270 million metric tons, which is equivalent to 5.6% of total annual U.S. CO2 emissions from energy consumption. The annual savings in operating costs for households and businesses totaled $105 billion, and the average household saved $576 in operating costs as a result of standards on residential appliances and plumbing products. The estimated cumulative past and future energy and water savings from these standards amount to 307 quads of energy and almost 53 trillion gallons of water. The estimated cumulative CO2 emissions reduction from the standards come to 10.3 billion metric tons. Accounting for the increased upfront costs of more-efficient products and the energy and water cost savings over the products’ lifetime, the standards have a cumulative net present value of benefit of $3.2 trillion using 3 percent discount rate and $3.5 trillion using 7 percent discount rate when discounting past and future benefits to 2024.