Size Your Water Heater First, Ensure Lasting Energy Efficiency
Riddle: How does a hot water heater not waste energy? Answer: When it’s properly sized. The water heater — or water heaters — in your greater Cincinnati home should have the capacity to easily meet your home’s high-demand-period needs yet operate efficiently without wasting energy — or water. Need sizing for a combination water/space heating system? See your HVAC contractor about your specific situation. How to size your water heater Tankless units are rated by the maximum temperature rise they can efficiently achieve at a certain water-flow rate. Calculate requirements for whole-house water heating and/or remote heating, such as for a bathroom in a guest house.
- Flow rate: Estimate how many hot water fixtures (sinks, showers, appliances) you expect to use at once, and total the flow rates in gallons per minute.
- Temperature rise: Subtract incoming water temperature from the necessary output temperature. A rule of thumb is to assume input water is about 50 degrees. Water heated to 120 degrees is normally fine for household use.