Expansion tanks for electric water heaters: the complete guide to avoid costly disasters

Electric water heaters are a staple in many homes, providing a constant supply of hot water for showers, baths, and other household tasks. However, one question that often arises is whether an electric water heater requires an expansion tank. This blog post will delve into this topic, exploring the necessity of expansion tanks for electric water heaters and providing valuable insights.

What is an Expansion Tank?

An expansion tank is a device installed in plumbing systems to absorb pressure fluctuations and prevent damage to pipes and fixtures. As water heats, it expands in volume. In a closed system like an electric water heater, this expansion can create excessive pressure, potentially leading to burst pipes or leaks.

Does an Electric Water Heater Need an Expansion Tank?

Yes, an electric water heater typically requires an expansion tank. This is because electric water heaters are closed systems, meaning there is no way for excess water to escape as it expands. Without an expansion tank, the pressure buildup could damage the water heater tank, pipes, and other components.

Types of Expansion Tanks

There are two main types of expansion tanks for electric water heaters:

• Closed Expansion Tanks: These tanks are sealed and contain a diaphragm that separates the water from a compressed air or nitrogen gas chamber.
• Open Expansion Tanks: These tanks are not sealed and are installed at the highest point in the plumbing system. They allow excess water to overflow into the tank and discharge it through a drain.

Sizing an Expansion Tank

The size of the expansion tank required for an electric water heater depends on the volume of the water heater tank. Typically, a tank size of 1 gallon per 50 gallons of water heater capacity is recommended.

Installation

Expansion tanks should be installed according to the manufacturer’s instructions. They are typically connected to the cold water inlet of the water heater and the highest point in the plumbing system.

Benefits of an Expansion Tank

Installing an expansion tank for an electric water heater offers several benefits:

• Prevents Pressure Buildup: An expansion tank absorbs excess pressure, protecting the water heater tank and plumbing system from damage.
• Extends Water Heater Life: By preventing pressure buildup, an expansion tank helps prolong the life of the electric water heater.
• Reduces Noise: Expansion tanks can minimize water hammer, a banging noise that occurs when water flow is suddenly stopped.

Signs of Expansion Tank Failure

A faulty expansion tank can lead to pressure buildup and potential damage to the electric water heater. Signs of expansion tank failure include:

• Leaking or dripping water from the tank
• Rust or corrosion on the tank
• Water hammer
• Excessive pressure readings on the water heater pressure gauge

What People Want to Know

1. Can I use a water heater without an expansion tank?

It is not recommended to operate an electric water heater without an expansion tank. The excessive pressure buildup can damage the water heater and plumbing system.

2. What happens if the expansion tank is too small?

An undersized expansion tank may not be able to absorb all the excess pressure, leading to potential damage.

3. How often should I inspect the expansion tank?

Regularly inspect the expansion tank for leaks or other signs of damage. Replace the tank if necessary.

4. Can I install an expansion tank myself?

While it is possible to install an expansion tank yourself, it is recommended to hire a licensed plumber to ensure proper installation.

5. How long do expansion tanks typically last?

Expansion tanks can last anywhere from 5 to 10 years, depending on the water quality and usage patterns.