For many U.S. homeowners, upgrading to an electric tankless water heater is a smart choice that combines energy efficiency with the convenience of on-demand hot water. Unlike traditional tank-based systems, which store and continuously reheat water, tankless units heat water as it flows through the unit, reducing energy waste and maximizing space efficiency. However, proper installation is essential for optimal performance, safety, and longevity of the system.
This article provides a detailed, step-by-step guide to installing an electric tankless water heater, drawing from multiple reliable sources, including manufacturer guidelines and professional installation best practices. The information is structured to cover essential preparation steps, installation procedures, and post-installation testing to ensure the system operates safely and effectively.
Preparing for Electric Tankless Water Heater Installation
Before beginning the installation process, homeowners must conduct thorough preparation to ensure safety and efficiency. This includes understanding and adhering to local building codes, verifying electrical and plumbing requirements, and gathering the necessary tools and materials.
Safety and Legal Compliance
Safety is the primary concern in any installation. Prior to starting work, locate and shut off the main circuit breaker that powers the existing water heater. This step is essential to prevent electrical hazards during the installation. Additionally, turn off the main water supply to avoid water leakage and potential damage.
Local building codes may require permits for the installation of new water heating systems. Homeowners are advised to contact their local building department to confirm any permit requirements and ensure compliance with safety standards. This step is particularly important for electrical and plumbing work, as improper installation can lead to system failures or safety risks.
Assessing Electrical and Plumbing Requirements
Electric tankless water heaters require a dedicated electrical circuit with sufficient capacity to support the unit. The unit's power requirements—often measured in kilowatts (kW)—determine the size of the circuit breaker and the thickness of the electrical wiring. Homeowners should consult the manufacturer’s specifications to determine the exact electrical requirements for their unit.
For plumbing, the existing pipes must be evaluated to ensure they are in good condition and compatible with the new tankless system. Copper or PEX (cross-linked polyethylene) pipes are commonly used for tankless installations due to their durability and flexibility. If the existing pipes show signs of corrosion or wear, they should be replaced to prevent leaks or inefficiencies.
Gathering Tools and Materials
Before starting the installation, assemble all necessary tools and materials. This includes:
- Adjustable wrench
- Pipe cutter or hacksaw
- Screwdrivers
- Teflon tape or pipe thread sealant
- Pipe fittings and connectors
- Shut-off valves
- Copper or PEX pipes
- Electrical wiring and conduit
- Circuit breaker
Having all tools and materials ready at the start of the installation reduces delays and helps maintain workflow efficiency.
Mounting the Electric Tankless Water Heater
Once the preparatory steps are complete, the next phase is mounting the unit in the appropriate location. Proper placement is crucial for both performance and accessibility.
Selecting the Installation Location
The ideal location for an electric tankless water heater is near the most frequently used plumbing fixtures. This minimizes the distance water must travel, reducing lag time when hot water is needed. Common installation locations include utility rooms, garages, or spaces adjacent to the kitchen and bathrooms.
It is also important to ensure that the installation location has adequate space for the unit and allows for proper ventilation if required. Some models may need a small amount of airflow to operate efficiently, so avoid placing the unit in enclosed areas without ventilation.
Mounting the Unit
Once the location is selected, the water heater must be mounted securely. Use wall brackets or a dedicated support structure to ensure the unit is stable and level. Secure the mounting hardware according to the manufacturer’s instructions to prevent movement or vibration that could damage the unit or connections.
Connecting Pipes and Valves
After the unit is mounted, the next step is to connect the water supply lines. This process involves cutting and preparing the pipes, installing shut-off valves, and ensuring all connections are watertight.
Planning the Piping Layout
Before cutting any pipes, measure and plan the piping layout. Determine the length of the cold water inlet and hot water outlet lines based on the unit’s inlet and outlet connections and the location of the existing plumbing. Accurate measurements help prevent unnecessary cuts and reduce the risk of leaks.
Cutting and Preparing Pipes
Use a pipe cutter or hacksaw to cut the pipes to the required length. After cutting, deburr the edges using a pipe reamer or sandpaper to remove any roughness that could interfere with the connections. Clean the inside of the pipes to ensure a smooth flow of water.
Installing Shut-Off Valves
Install shut-off valves on both the cold water inlet and hot water outlet lines. These valves allow homeowners to isolate the tankless water heater for maintenance or repairs without shutting off the entire home’s water supply. Ensure the valves are securely fastened and aligned with the pipe connections.
Securing Connections
Apply Teflon tape or pipe thread sealant to the threads of the pipe fittings before securing them. This helps create a watertight seal and prevents leaks. Use a pipe wrench or adjustable wrench to tighten the fittings, but avoid over-tightening, which can damage the threads or fittings.
Once all connections are made, visually inspect them for any signs of misalignment or gaps. A well-sealed system ensures efficient operation and minimizes the risk of water damage.
Electrical Connections
After the plumbing is complete, the next critical step is connecting the electrical components. This process requires careful attention to detail and adherence to electrical safety standards.
Verifying Electrical Requirements
Before connecting the unit, confirm the electrical specifications provided by the manufacturer. This includes the required voltage, amperage, and circuit breaker size. Use a multimeter to test the existing circuit and ensure it meets the unit’s requirements.
If the existing circuit is insufficient, a licensed electrician may need to install a new circuit with the appropriate breaker. This step is crucial for the safe operation of the unit and to prevent electrical overloads.
Installing the Circuit Breaker
Install a dedicated circuit breaker in the main electrical panel. The size of the breaker must match the unit’s electrical requirements. For example, a 12 kW tankless water heater may require a 60-amp breaker. Secure the breaker according to local electrical codes and manufacturer guidelines.
Running Electrical Wiring
Run the electrical wiring from the main panel to the location of the water heater. Use conduit to protect the wires and prevent damage. Secure the conduit to the wall and connect it to the unit’s electrical terminal box.
Follow the manufacturer’s wiring diagram to connect the wires to the unit’s terminals. Double-check all connections for tightness and proper labeling. Once the connections are made, cover the terminal box with a protective cover to prevent exposure to moisture or dust.
Testing and Adjusting the System
After the installation is complete, the system must be tested to ensure it operates safely and efficiently. This process includes checking for leaks, verifying water flow, and adjusting the temperature settings.
Turning on the Water Supply
Before testing the system, slowly turn on the main water supply. Allow water to flow through the pipes to flush out any debris that may have accumulated during installation. Check all connections for leaks and tighten any fittings that appear loose.
Testing the System
Open a hot water faucet to test the system. The tankless water heater should begin heating the water immediately. Monitor the flow and temperature to ensure the system is functioning as expected.
Use a thermometer to check the water temperature at the faucet. Adjust the temperature settings on the unit if necessary. Most tankless water heaters have digital controls that allow for precise temperature adjustments.
Inspecting Electrical Connections
After the system is running, inspect the electrical connections again to ensure they are secure and free of damage. Check the circuit breaker to confirm that it is not tripping under normal operation.
Conclusion
Installing an electric tankless water heater is a complex but rewarding project that offers long-term energy savings and improved convenience. By following the steps outlined in this guide—ranging from safety preparations and pipe connections to electrical installations and system testing—homeowners can ensure a successful and efficient installation.
It is important to note that while this guide provides detailed instructions, some aspects of the installation may require the assistance of a licensed professional. If any part of the process is unfamiliar or uncertain, homeowners should consult with a qualified plumber or electrician to ensure the system is installed safely and in compliance with local regulations.
By taking the time to understand the installation process and following best practices, homeowners can enjoy the benefits of an electric tankless water heater for years to come.