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.
Electric instant hot water heater sizing.
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.
The right size is a tankless water heater that can heat enough gallons of water to a specific temperature per minute to keep up with the demand.
For example an electric tankless heater that is rated at raising the water temperature 55 degrees at 1 5 gpm will supply you with a 120 degree temperature if the incoming water is 65 f or higher.
Most demand water heaters are rated for a variety of inlet temperatures.
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.
In fact it is the most important part of choosing a new unit for your home.
Tankless water heaters are intended to heat potable drinking water only and the inlet water to a tankless unit should not be pre heated.
This tool is intended only for use as a guide to the products we offer that meet certain criteria you may be looking for.
Sizing storage and heat pump with tank water heaters.
Tankless water heater sizing calculator.
The tankless water heaters shown here may or may not be suitable for your application depending on other factors such as wiring electrical needs home plumbing configuration water quality and more.
Rheem performance tankless electric water heaters help reduce rheem performance tankless electric water heaters help reduce energy usage save on energy costs and provide the comfort and convenience of continuous hot water on demand.
Now you need to understand what temperature rise means.
Choose the right tankless electric water heater for you.
Rheem tankless electric water heaters make it easy to enjoy instantaneous continuous hot water space saving design and significant energy cost savings.
Size matters when it comes to your tankless water heater.
We already covered gpm.
Having a water heater that is too small will result in it not being able to produce enough hot water for your household demand.
Our whole home models are a perfect match for installations in small spaces and no venting is required.
Pro size is intended to assist in selecting water heaters or boilers that best meet the specific job requirements.
Gas tankless water heaters are able to produce a larger temperature rise per gpm than electric models.
Smith pro size sizing program is a tool that can be used to estimate water heater requirements for many common applications.