Helping your family or your customers determine their water heating costs for the year just got easier. Simply enter your home size and location, and specify some details about your water heating system (energy source, age of system, fuel costs, etc.), and the Water Heating Energy Calculator does the rest. In addition to your estimated annual energy cost, the app will also calculate expected CO2 emissions from the system you've described. Homeowners that are getting ready to upgrade their water heating can enter details for a second system - including installation costs and available rebates or incentives - to compare results side-by-side. With two systems to compare, the app will also calculate how long it will take to break even on the investment.