It really does depend on the type of energy-efficiency project you're putting in place. If you think of a retail building, you're using energy to heat and cool the building, for lights, computers and whatnot. You can make some relatively low-cost changes, for example, lighting or smart thermostats, which will have a relatively quick payback. In some cases, you're looking at less than a year payback on those products.
You could also look at what we often refer to as deep retrofits. For that building, you could look at heavy insulation in that building, glazing the windows, putting in building systems and controls. Those types of projects have a much longer payback and you're into the five-year or ten-year period. It really does depend on what type of an initiative you put forward.