Electric Hot Water Heater: What Size Wire Do I Need?

Got an electric hot water heater taking up space in your garage or basement? Well, you can finally give it a purpose by finding the right size wire for it.

An electric hot water heater is a great option for central heating or for just heating the water throughout the home. 

Electric Hot Water Heater: What Size Wire Do I Need?

However, with so many types of electric hot water heaters out there it can be hard to know what size wire you need to get it going. That’s where we come in! 

Below you will find everything you need to know about electric hot water heaters including the different types, a short buyer’s guide, and what size wire you need to keep things running smoothly. 

Let’s dive in! 

What Is An Electric Hot Water Heater?

An electric hot water heater is a device that heats water for usage across a home using electricity rather than gas.

Electric water heaters can heat water in a tank or without a tank, as well as at the point of use or in a central place. 

By concentrating existing heat from the air into the water with the help of a hybrid or heat pump system, electric water heaters can also be very energy-efficient.

What Size Wire Is Needed?

There are more than a few different types and sizes of electric hot water heaters, meaning they all require a different size wire.

This can make it seem impossible to know what size your electric hot water heater needs but never fear, we have broken it down for you!

A 12-gauge wire is required for a 20-amp water heater while a 10-gauge wire for a 25-amp water heater. On the other hand, an 8-gauge wire is for a 30- to 40-amp water heater.

When wiring a water heater, it is advisable to use a wire that is larger than is required.

Let’s break it down further:

    • 25 Amp Water Heater = 10 Gauge Wire 

    • 40-30 Amp Water Heater = 8 Gauge Wire

A man adjusts the settings on a electric water heater mounted on a light blue wall. RV Lifestyle Experts

Types Of Electric Hot Water Heaters 

Now that we know how to figure out which size of wire we need depending on the amperage of your water heater, it is time to discuss the types of water heaters out there. 

There are 3 main types of electric hot water heaters on the market:

Conventional Water Heaters 

the conventional method, in which the water is heated by electric heating elements inside an electric water heater tank.

The amount of hot water you have accessible depends on the size of the tank, and it is always kept warm.

The temperature control shutoff and the stress control shutoff are two of the shutoffs included in this container.

When the temperature rises above 120 degrees, the temperature level control shutdown opens up to release some heat.

When the pressure reaches about 150 psi, the stress control shutdown opens to release the stress. 

This is the most common type of electric water heater across the US but it comes with its own set of disadvantages.

You are limited on how much water the tank can hold meaning if you run out, you are going to need to wait for a new tank to heat up which can take some time. 

Tankless Water Heaters 

Instantaneous (or “tankless”) water heaters heat water only as needed by using super-heated electric coils in place of a tank.

These may be positioned in the center of the area or close to the water’s intended use.

These come in various sizes and are excellent for big families. They work well in homes with extensive gas lines and are better suited to homes that run on gas.

Some tankless water heaters rely on electricity to operate. However, these models typically consume a lot of energy.

As a result, in order for some households to operate securely, their electrical capacity may need to be upgraded.

Once you pay the hefty installation fee, you may find that you end up saving energy and money over time. 

Hybrid Water Heaters

The hybrid electric water heater, also referred to as a heat pump water heater, is an emerging technology that delivers hot water more efficiently.

A hybrid electric water heater raises the temperature of the water by transferring heat from the ground and surrounding air into it. They are different to traditional and tankless water heaters which employ a heating element.

Since the heating element is not powered by electricity, this procedure improves the energy efficiency of your water heater technology.

The device may provide your home with the hot water it needs with less overall energy use and more reliably by utilizing ambient heat.

Hybrid water heaters are becoming increasingly popular among homeowners. The reason is that they see a significant reduction in their utility bills and the overall quality of warm water throughout their homes. 

Electric Hot Water Heater What Size Wire Do I Need (1)

Things To Consider 

Before you go purchase a brand new water heater, there are a few features to be considered. Such as:

    • Digital Display: With a digital display, checking water levels and temps is simple. This choice eliminates all uncertainty associated with water heater ownership.

    • Tank Size: Consider the appropriate water heater size for your household or yourself. The size of the tank you select should be able to readily provide your household with enough hot water each day.

    • Warranty: The type of warranty you will receive when you buy a water heater should be investigated. The typical duration of a water heater warranty is between three and twelve years. The 12 year coverage will cost a little more, so be prepared.

    • Energy Efficiency: When searching for an electric water heater it should be Energy Star certified to ensure it is highly efficient. 

Benefits Of Electric Hot Water Heaters 

As the world begins to see the future with using electric energy over gas, there are many benefits that come with it.

Much like swapping your gas stove for an electric one or even an electric car. 


Electric water heaters are a lot more efficient than gas. They lose minimal energy when heating water. Also, they help bring down utility bills and provide you with a better energy source overall. 

A person adjusting the temperature setting on an electric water heater. RV Lifestyle Experts

No Gas Leak 

One of the biggest fears of working with gas is the risk of a gas leak and the production of carbon monoxide. There is no risk of a gas leak when you have an electric water heater. 

This is a great benefit for everyone as it is better for the environment and you can sleep easy knowing that there is no chance of a gas leak throughout the night. 

Cost Effective 

Due to having no need for fuel, electric water heaters are significantly cheaper to operate. They use electricity and water which will allow you to stop having a gas bill. 

Your electricity bill may rise but over time it will still be more cost-effective to have an electric water heater installed than a gas one. 

Hot Water 

Electric water heaters are made to maintain a constant temperature and to deliver hot water. Of course, the insulation of the water heater directly affects the temperature inside the tank.

Once the electric water heater is installed, you simply need to wait for the water to come to the right temperature and you will have access to constant hot water. 

Final Thoughts 

Electric water heaters are a great way to heat water and to generate electricity without causing your bills to skyrocket. However, knowing which size wire to use can be tricky. 

The size wire you need is dependent on the amperage of your electric water heater. The bigger the amperage, the smaller the wire. 

Remember to use a wire which is slightly larger than you need in order to ensure it is wired correctly. 

Now you can wire up your electric water heater and experience the bliss that is running hot water. 

Frequently Asked Questions 

What Are The Disadvantages Of Electric Water Heaters?

An electric water heater has the following drawbacks: usually requires more maintenance costs.

Unless there is a power source, it won’t function during power outages. less water is heated in an hour.

Are Electric Water Heaters Expensive To Run?

On average electric water heaters can cost around $42 a month to run making them extremely cost-effective. 

What Is The Cheapest Way To Heat Water?

Natural gas is one of the most cost-effective ways to heat water. However, electricity is also a cheap method for heating water with propane being the most expensive. 

Eddie Meyers
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Eddie Meyers
My name is Eddie, and I am an RV enthusiast! I have enjoyed traveling all my life, and want to give my family the same opportunities to see as much of the world as possible. As I’ve gotten older, I’ve discovered how great RVs can be for vacations with a young family. Here at RV Lifestyle Experts, I want to share my experiences, the tips I’ve picked up along the way. I hope that our guides can encourage you to try the RV lifestyle. I promise you that you won’t regret it!
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