Because water system upgrades are typically expensive, the payback for performing them needs to make financial sense. Regardless of the specific duration of the payback, it and the cost of the work are vitally important, so these calculations need to be accurate.
Unfortunately, most water efficiency payback calculators don't include all of the savings that would shorten the payback period. Even worse, as a result, missing these cost savings may kill a project that could have moved forward had it been calculated differently.
A recent article in Building Operating Management covers the various considerations that are crucial to creating an accurate payback calculator.
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