Electric Instant Hot Water Heater Sizing

Sizing storage and heat pump with tank water heaters.

Electric instant hot water heater sizing.

Looking to purchase a new tankless water heater but having trouble figuring out what size or model you need. Gas tankless water heaters are able to produce a larger temperature rise per gpm than electric models. 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. 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.

Tankless water heaters are intended to heat potable drinking water only and the inlet water to a tankless unit should not be pre heated. Now you need to understand what temperature rise means. Choose the right tankless electric water heater for you. For example you might not be able to run more than one shower at a time without someone getting an arctic blast of cold water.

Before we get to how to use the calculator to size a tankless water heater let s talk about the factors that go into understanding what size inline water heater you need. Rheem tankless electric water heaters make it easy to enjoy instantaneous continuous hot water space saving design and significant energy cost savings. 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. Size matters when it comes to your tankless water heater.

In fact it is the most important part of choosing a new unit for your home. 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. 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. How to size a 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. We already covered gpm. Just follow the three simple steps below to choose the right model and size you need. You need a proportional amount of energy or kw to heat the flow or gpm you need for your application.

Use our handy calculator to determine your needed flow rate and temperature rise then find models that match your needs. The first factor in choosing a tankless water heater is calculating the size of your hot water heater. Having a water heater that is too small will result in it not being able to produce enough hot water for your household demand.