If you're making the switch from a traditional water heater with a tank to a tankless model, you should be aware that a tankless heater could require an electrical upgrade. If you have an older home, the electrical panel and wiring may not be sufficient for the demands of a tankless heater.
You could even need an upgrade if you live in a new home depending on the available space in your electrical panel. You may want to call an electrician to check your service panel before you buy your new water heater. Here's a look at what might be required.
A New Service Panel
If your home is several decades old, it might benefit from a new electrical panel. A tankless water heater needs a dedicated circuit, and even if your current heater has a dedicated circuit, it won't be powerful enough for a tankless heater. It may seem like a big expense, but when you live in an older home, the service panel has to be upgraded at some point, and a new panel will benefit you in other ways.
A Sub-Panel Or New Circuits
If your electrical panel is fairly new, you might need to have more circuits or a sub-panel added to it rather than replace the panel. This work will probably need to be done by a licensed residential electrical contractor to comply with local codes. The contractor will install the new circuit according to current electrical codes and the requirements for the type of heater you buy.
Tankless water heaters come in different sizes, and they have different power requirements when it comes to amps and the size of the wiring. You'll want to consider the electrical needs of the unit you choose carefully and talk to a contractor if you don't understand how to match a heater with your electrical system.
Unless you have a new home that's already wired for a tankless water heater, it's likely the electrician will need to run new wiring from the electrical panel to the heater. Be sure to have the location of your new heater already selected. You may even want input from the electrician on a good place for the heater based on the distance from the service panel.
The wiring that supplies electricity to the rest of your home cannot handle the amount of power needed for a tankless water heater. If the heater is connected to old wiring, the wiring can get so hot that it starts a fire.
A tankless heater works differently than a tank model. A tankless heater needs a huge surge of energy for a short period of time compared to a tank model that uses a lower amount of energy over the long term. The two types of heaters have very different energy needs and different electrical requirements.
Contact a residential electrical contractor in your area to learn more.