What Size Tankless Water Heater Do I Need To Replace A 50 Gallon Water Heater

Tankless water heaters are rated by the maximum temperature rise possible at a given flow rate.

What size tankless water heater do i need to replace a 50 gallon water heater. Simply locate the appropriate water heater sizes on ecomfort using your information. Smith 50 gallon proline power vent water heater available from supplyhouse has an fhr of 90 gallons so it will provide up to 90 gallons of hot water in an hour. A low flow shower head may use 1 5 gallons of hot water per minute or gpm as it is called. While traditional hot water tanks are compared based on gallon capacity recovery rate and first hour rating tankless hot water heaters are compared based on flow rate.

How to size a tankless water heater. Once you have your total flow rate and the required temperature rise you can find the right size tankless water heater for your home. Tankless water heater efficiency is determined by the water flow rates inside your home. To properly size a storage water heater for your home including a heat pump water heater with a tank use the water heater s first hour rating.

The first factor in choosing a tankless water heater is calculating the size of your hot water heater. For example the a. Below we ve highlighted what size water heater you would need in our example of 6 5 gpm at a 63 f temperature rise. 7 gpm gas tankless heater or at least a 18 kw electric tankless water heater if you live in the southern part of the usa.

Sizing storage and heat pump with tank water heaters. While traditional tank water heaters are calculated by your family size a tankless water heater is calculated by the quantity and types of fixtures or appliances it will serve. If you have considered upgrading your tank size from 40 or 50 gallons to 66 or 80 gallons we strongly recommend a tankless hot water heater. If you want to upgrade your water heater size from 40 or 50 gallons storage water heater or replace it you won t necessarily need a big tankless water heater.

The first hour rating is the number of gallons of hot water the heater can supply per hour starting with a tank full of hot water. If you do the math for 50 temperature rise you need approximately 25 000 btu s per hour per gpm of water required which doesn t take heater efficiency into account but gives a good idea of the size of high efficiency heater needed. Therefore to size a demand water heater you need to determine the flow rate and the temperature rise you ll need for its application whole house or a remote application such as just a bathroom in your home.