3 years ago CU student leaders invested聽$500,000聽in an endowment for energy-efficient projects.聽37.8聽percent is the annual return on investment for the CU green fund. $24,000聽is the amount the school saved in efficiencies because of fund-related projects in its first year, followed by $59,583 last year and $143,500聽this year. Projects include replacing radiator values and windows and switching to LED lights and must have payback periods under 5聽years.