Residential Tankless Water Heaters
Selecting tankless hot water heaters for the home isn't very difficult. Select one based on the maximum amount of hot water to meet your peak demand. Use the following assumptions on flow for various appliances to find the size of unit that is right for your purposes:
Faucets: (0.75 to 2.5) per minute.
Low-flow shower heads: 1.2 gallons to 2 gallons per minute. Older standard shower heads: 2.5 gallons) to 3.5 gallons per minute.
Clothes washers and dishwashers: 1 gallon to 2 gallons per minute.
In the Greater Cincinnati area the groundwater temperature coming into your house is about 53 F You will want your water heated to 120° F (49° C) for most uses, or 140° F (60° C) for dishwashers without an internal heater. To determine how much of a temperature rise you need, subtract the incoming temperature from the desired output temperature. In this example, the needed rise is 67 degrees F.
List the number of hot water devices you expect to have open at any one time, and add up their flow rates. This is the desired flow rate for the heater.
With this information, Elliott and Bradley Plumbing will work with you to calculate the best tankless water heater solution for your needs.