Home Home Whether you own or rent your home, explore ways to save money and improve the comfort of your home. Start Saving Business No matter the size of your business, there are energy-saving opportunities to save money and time. Start Saving Multifamily Increase the value of your building, lower operating costs, and improve tenant comfort by making your property more energy efficient. Start Saving Home Business Multifamily Contractors Who is Ameren Illinois? We’re committed to helping customers find ways to improve comfort, manage usage, and reduce costs. In 2020, the Ameren Illinois Energy Efficiency Program saved our customers more than $33 million in energy costs. Learn more about us