Upgrading a chiller, installing a solar photovoltaic system, undertaking a deep whole-building retrofit—all these projects require large upfront investments and have long payback horizons even as they deliver operational savings. External funding and innovative finance may complement the use of internal capital or operating budgets to support investments.  And increasingly, new metrics for value are reshaping the discussion from straight financial “return on investment” of a technology to new metrics on building asset value and achieving co-benefits such as improvements in productivity, environment, health, and resilience. Photo Credit: Michael Fleshman/Flickr