Switching from a storage tank water heater to a tankless water heater system yields many benefits, including energy savings of up to 50 percent, a system that has nearly twice the lifespan, and a continuous flow of hot water that won’t leave you shivering if you’re the last one in line for the shower.
Sizing up your water heater
To achieve these benefits, and gain maximum performance, your tankless water heater system must be accurately sized. This includes many variables, such as household size, distance to the furthest hot-water appliance or outlet, energy source (electric or gas system), and, most importantly, the temperature rise and flow rates of your home and water heater.
Temperature rise and flow rate
Temperature rise is the the total degrees that in-flowing ground water must be heated to reach your desired hot water output temperature. You may use a thermometer to measure cold water temperatures at all outlets to get an average. Subtract that temperature from your desired hot water temperature (e.g. in-flowing water temperature minus 120 degrees). That’s your household’s temperature rise.
Flow rate is the number of gallons per minute (GPM) that each outlet or appliance provides. The sum of all outlets/appliances in simultaneous use is your household’s flow rate. The flow rate of your tankless water heating system is the amount of hot water in GPM that it’s capable of providing.
Gas or electric system
Toe to toe, a gas-heated whole-house system is more energy efficient than a whole-house electric system. However, smaller electric units may be installed near hot water outlets, such as the kitchen sink, dishwasher, remote bathroom sinks and other locations and appliances (depending on your home’s design), which significantly reduces water heating costs and the time it takes to receive hot water.
If you work step by step with your HVAC professional, you can easily design a tankless water heater system that saves energy and provides your family with a reliable and continuous supply of hot water. Contact the water-heating experts at Stack Heating & Cooling. We’ve proudly served northeast Ohio since 1976.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about tankless water heaters and other HVAC topics, download our free Home Comfort Resource guide.