Water Heater Installation: Tankless & Gas Units Guide

Did you know that water heating, especially with tankless gas or electric units, accounts for about 18% of your homes’ energy use? Upgrading your water heater can lead to significant cost savings and improved efficiency. Whether it’s a traditional hot water heater or a modern tankless system, proper installation is key to maximizing performance and longevity. From ensuring the right size for your household needs to optimizing energy efficiency, a professional installation can make all the difference in your daily comfort and utility bills. Stay tuned as we delve into the essential aspects of tankless water heater installation, guiding you through the process, including vent and cover, and highlighting the benefits of this crucial home upgrade.

Preparing for Installation

Clearing Area

Clear the installation area of any obstacles to ensure a smooth process. This step helps create a safe working environment.

Gathering Tools

Gather all necessary tools and materials before starting the installation. This includes wrenches, pipes, fittings, and the new tankless water heater itself.

Shutting Off Supplies

Shut off the water and gas supply to the current heater prior to beginning work. This is crucial for safety reasons.

Upgrading Your Gas Line

Check Compatibility

Before proceeding with the water heater installation, it is crucial to assess the compatibility of your current gas line. Ensure that the existing gas line can support the requirements of your new water heater. Inadequate gas lines can lead to inefficiencies and potential safety hazards.

Consult Professionals

If you are uncertain about whether your gas line needs upgrading, it is advisable to seek guidance from qualified professionals. Gas line installations, including tankless water heater, require precision and expertise to guarantee safety and optimal performance. Consulting experts will help you determine if any upgrades are necessary.

Ensure Proper Ventilation

Proper ventilation is essential when upgrading your gas line for a new water heater installation. Adequate airflow ensures the safe operation of your water heating system and prevents the accumulation of harmful gases. Ventilation considerations are critical for maintaining a healthy indoor environment.

Removing the Old Water Heater

Draining Process

Begin by draining the old water heater entirely to avoid any spills or leaks during removal. Attach a garden hose to the drain valve at the bottom of the tank and direct the other end to a suitable drainage area. Open the valve and let the water flow out until the tank is empty.

Disconnecting Connections

Next, disconnect both the electrical and plumbing connections from the current water heater. Turn off the power supply to the water heater from the circuit breaker to ensure safety. Then, shut off the water supply and disconnect the pipes attached to the heater.

Removal Procedure

To safely remove the old water heater from its position, ensure that it is completely drained and all connections are detached. Use caution while handling the unit as it can be heavy and cumbersome. Depending on your setup, you may need assistance in lifting and carrying it out.

Mounting the New Heater


Position the new heater in the designated spot, aligning it properly with the existing connections. Ensure that it is level to prevent any future issues.

Secure the heater by attaching it to the wall using appropriate mounting brackets. This step is crucial for stability and safety reasons.

Ventilation Spacing

Allow for sufficient space around the heater to ensure proper ventilation. A minimum of 6 inches of clearance on all sides is recommended for optimal performance.

Create a secure and sturdy mount for the heater, ensuring that it is firmly in place. This prevents any potential accidents or damage due to improper installation.

Avoid blocking any vents or openings when mounting the heater to maintain consistent airflow and prevent overheating issues.

Installing the Gas Line

Connect Gas Pipe

Connect the gas pipe from the main line to the gas units on the new water heater. Ensure a secure and tight connection.

Test for Leaks

After connecting, test for gas leaks by applying a soapy water solution to all connections. Look for bubbles indicating leaks.

Secure Connections

Secure all connections tightly using appropriate tools to prevent any potential gas leaks. This step is crucial for safety.

Setting Up New Water Lines

Local Plumbing

Local plumbing regulations must be adhered to when setting up new water lines for your water heater installation. Ensure compliance with any specific requirements in your area.

When installing new water lines, it is crucial to follow the pipe sizing guidelines provided by the manufacturer. Properly sized pipes ensure efficient water flow and prevent issues such as low water pressure.

Pipe Settings

During the hot water heater installation, pay close attention to the pipe settings. Properly aligning and securing the pipes is essential for the overall functionality of the system. Any misalignment can lead to leaks or reduced water flow.

Using high-quality materials for the pipes is key to ensuring longevity and preventing future leaks. Opt for durable materials that are recommended for use in tankless water heater installations.

Insulating Water Lines

Insulate water lines after setting them up to minimize heat loss and improve energy efficiency. This step is crucial, especially if the water heater is located in a cold environment or basement where temperatures can drop significantly.

Proper insulation not only helps maintain hot water temperatures but also reduces the workload on the water heater, leading to lower energy bills over time.

  • Use foam pipe insulation sleeves to wrap around the exposed pipes.
  • Ensure all joints and connections are properly sealed to prevent heat loss.
  • Insulate both hot and cold-water lines for optimal efficiency.

Adding a Pressure Relief Valve

Installing Valve

To enhance safety during the water heater installation, it is crucial to add a pressure relief valve. This valve plays a vital role in releasing excess pressure, preventing potential hazards.

Ensure that the pressure relief valve you install is specifically rated for the specifications of your new water heater. Compatibility is key to ensure optimal performance and safety.

Testing Functionality

After installing the pressure relief valve, it’s essential to conduct a thorough test. To verify proper functioning, simulate high-pressure scenarios and observe if the valve effectively releases pressure.

  • The valve should be able to handle the maximum pressure that the water heater can generate.
  • Regularly check and maintain the pressure relief valve to ensure it remains in good working condition.

Installing the Exhaust Vent

Determining Location

When installing a water heater, determine the optimal location for the exhaust vent to ensure proper ventilation. Consider proximity to windows and doors.

Following Codes

Adhere strictly to local building codes when installing the vent system for your water heater. Compliance ensures safety and efficient operation.

Sealing for Safety

Properly seal all connections with screws and fittings to prevent gas leaks in the exhaust vent system. Ensure airtightness for safety.

Activating the Water Supply

Filling the Heater

Begin by slowly turning on the water supply to allow the new water heater to fill up. This gradual process ensures proper filling without causing any sudden pressure issues.

Ensure that the hot water heater is adequately filled before proceeding with further checks. Proper filling prevents damage and ensures optimal performance.

Checking for Leaks

Inspect all water lines connected to the faucet for any signs of leaks. Even minor leaks can lead to significant problems if left unattended.

Use a keen eye to identify even the smallest drips or seepages along the water lines. Addressing leaks promptly prevents water wastage and potential damage.

Verifying Functionality

Before regular use, it’s vital to verify that the tankless water heater is functioning correctly. Testing its operation ensures a seamless experience when using hot water.

Turn on the electricity supply and observe the heater’s response to ensure it heats water efficiently. Proper functionality guarantees a continuous supply of hot water as per demand.


You’ve now learned the essential steps for a successful water heater installation, from preparation to activation. By upgrading your gas line, removing the old heater, and mounting the new one correctly, you ensure a safe and efficient setup. Installing the necessary gas and water lines, along with safety features like a pressure relief valve and exhaust vent, guarantees a reliable hot water supply. Remember to activate the water supply to complete the process.

For a hassle-free installation experience and long-term functionality of your water heater, following these steps diligently is crucial. Now that you’re equipped with the knowledge, go ahead and tackle your water heater installation confidently. Your diligence will pay off with a steady flow of hot water in your home.

Frequently Asked Questions

How should I prepare for a water heater installation?

To prepare, clear the area around the old water heater, ensure all necessary tools are available, and review the manufacturer’s installation instructions. Turn off the gas and water supply before starting.

What is the benefit of upgrading my gas line during water heater installation?

Upgrading your gas line ensures proper fuel supply to your new water heater, preventing potential safety hazards and improving its efficiency. It also meets current building codes for safe operation.

Do I need to remove the old water heater myself before installing a new one?

It is recommended to have a professional plumber remove the old water heater as it involves disconnecting gas and water lines safely. This ensures proper disposal of the old unit and avoids any damage during removal.

Why is it important to install a pressure relief valve during a water heater installation?

A pressure relief valve safeguards against excessive pressure buildup in the water heater, reducing the risk of explosions or leaks. It is a crucial safety feature that protects both your property and your family from potential hazards.

How can I activate the water supply after completing the installation?

Once all connections are secure, slowly turn on the main water supply valve to allow water to flow into the new heater. Check for any leaks and ensure proper functioning of the unit before fully restoring hot water usage in your home.


Get expert guidance on water heater installation, including tankless and gas units. Step-by-step guide for DIY or professional installation.