Can You Vent a Tankless Water Heater With PVC: Find Out Now!

Debarghya Roy

Tankless Water Heater With PVC

If you’ve recently switched to a tankless water heater, figuring out the venting process can be puzzling. Did you know PVC or CPVC piping is commonly used for this purpose? This article provides a comprehensive guide on how to vent your tankless water heater using PVC, ensuring efficiency and safety in your home.

Get ready to master the art of ‘venting’ in just minutes!

Tankless water heater

Key Takeaways

  • Venting a tankless water heater with PVC is crucial for safe and efficient operation, as it expels harmful gases like carbon monoxide outside.
  • Different types of venting options are available for tankless water heaters, including power-vent, direct-vent, concentric venting, and vertical venting.
  • The step-by-step process for venting a tankless water heater with PVC includes consulting the manufacturer’s manual, determining the vent location, gathering necessary tools and materials, measuring and cutting PVC pipes, assembling components securely, installing supports for horizontal sections, attaching a termination cap at the end of the pipe to prevent debris entry and inspecting the entire system for leaks before testing functionality.
  • It is essential to follow safety precautions such as wearing protective gear, turning off power supply before work begins and consulting professionals if uncertain or unfamiliar with installation processes.

Understanding the Venting Requirements for a Tankless Water Heater

Tankless water heaters require proper venting to ensure safe and efficient operation. Different types of venting options, such as power-vent or direct-vent, are available for tankless water heaters.

Why tankless water heaters require venting

Venting plays a crucial role in the functioning of tankless water heaters. These modern heating systems are designed for efficiency, but they produce exhaust gases during operation that need to be safely expelled.

Without proper venting, these harmful exhaust gases, which include carbon monoxide—a colorless and odorless gas—can accumulate indoors and pose serious health risks. Besides safety concerns, correct vent installation maintains optimal performance levels of your heater by ensuring adequate air supply for combustion.

Missteps like using incorrect piping material or a improper vent location can hinder performance and pose threats to safety as highlighted in common issues with tankless water heater installations.

The importance of proper venting

Proper venting is crucial when it comes to tankless water heaters. It ensures the safe and efficient operation of the unit while also maintaining indoor air quality. Without proper venting, harmful gases such as carbon monoxide can build up inside your home, posing a serious health risk to you and your family.

Venting allows these gases to be safely expelled outside.

In addition to safety concerns, proper venting also helps in preventing damage to the water heater itself. Improper venting can cause backpressure and restrict airflow, leading to poor combustion and reduced efficiency.

Different types of venting options for tankless water heaters

There are several different venting options available for tankless water heaters. Here are the main types:

  1. Power-Vent: This type of venting system uses indoor air for combustion and then vents the exhaust gases outside. It requires a blower to push the gases out through a PVC or CPVC pipe.
  2. Direct-Vent: In direct-vent systems, air is drawn in from outside for combustion, and the exhaust gases are also vented outside through a separate pipe. This type of venting is commonly used when there is no access to existing chimneys or flues.
  3. Concentric Venting: Concentric venting utilizes a single pipe that serves both as an intake for combustion air and an exhaust outlet for the flue gases. This helps streamline the installation process and reduces the number of holes required in walls or roofs.
  4. Vertical Venting: For tankless water heaters installed in basements or other locations below ground level, vertical venting is often used. Vertical vents allow for proper air flow and ensure that carbon monoxide does not accumulate in enclosed areas.

Venting a Tankless Water Heater with PVC

To vent a tankless water heater with PVC, follow this step-by-step guide using the required tools and materials while taking necessary safety precautions.

Step-by-step guide for venting with PVC

Venting a tankless water heater with PVC is a straightforward process that can be done by following these steps:

  1. Consult the manufacturer’s manual: Before starting the venting installation, carefully read the manual provided by the manufacturer. This will provide specific instructions and guidelines for your particular tankless water heater model.
  2. Determine the venting location: Decide on the best location to install the vent pipe. It should be positioned in an area where it can be easily accessed for maintenance and repair.
  3. Gather the necessary tools and materials: You will need a few tools and materials to complete the venting installation, including PVC pipes, connectors, elbows, screws, screwdriver, pipe cutter, silicone sealant, and a ladder (if installing through the roof).
  4. Measure and cut the PVC pipes: Using a pipe cutter or hacksaw suitable for cutting PVC pipes, measure and cut the required lengths of pipes according to your venting configuration plan.
  5. Assemble the PVC components: Begin assembling the PVC components by connecting them with elbows or connectors as needed. Ensure that each connection is secure and properly aligned.
  6. Install supports for horizontal sections: If you have any horizontal sections in your venting system, use supports such as metal brackets to keep them stable and prevent sagging.
  7. Attach the termination cap: Install a termination cap at the end of the vent pipe to prevent debris from entering and to provide proper ventilation.
  8. Inspect for leaks: Once all components are securely connected, inspect the entire venting system for any signs of leakage. Apply silicone sealant at joints if necessary.
  9. Test functionality: After completing the installation, test your tankless water heater to ensure that it is functioning properly with proper ventilation.

Required tools and materials

To properly vent a tankless water heater with PVC, you will need the following tools and materials:

  1. Drill: To create holes for mounting brackets or straps.
  2. Hole saw: For cutting holes in walls or ceilings for vent pipe installation.
  3. Screwdriver: For attaching brackets or straps to secure the vent pipe.
  4. Measuring tape: To measure the distance between the water heater and where the vent termination will be located.
  5. Level: To ensure that the vent pipe is installed correctly and level.
  6. PVC or CPVC pipe: The main material used for venting tankless water heaters. PVC is more common, but CPVC can also be used depending on local codes and regulations.
  7. Vent elbows, tees, and connectors: These fittings are needed to navigate corners and connect different sections of the vent pipe.
  8. Vent termination kit: This includes a rain cap, exhaust hood, bird screen, and any other necessary components for safely terminating the vent outside your home.
  9. Fasteners: Screws or nails may be required to secure brackets or straps to hold the vent pipe in place.
  10. Pipe primer and cement: Used to bond PVC or CPVC pipes together securely.

Image of Tankless Water Heater with PVC

Safety precautions

To ensure a safe and successful ventilation process for your tankless water heater, it is important to take the following safety precautions:

  1. Wear appropriate protective gear, such as gloves and safety glasses, to protect yourself from any potential hazards.
  2. Make sure to turn off the power supply to the water heater before starting any work. This will prevent any electrical accidents or shocks.
  3. Always refer to the manufacturer’s instructions and guidelines for venting your specific tankless water heater model. Following these instructions is crucial to ensure proper installation and avoid any potential dangers.
  4. When working with PVC piping, ensure that it is properly secured and supported. This will prevent any accidental dislodging or damage to the venting system.
  5. Take extra caution when working on roofs or in high areas. Use proper fall protection equipment and secure yourself to prevent any accidents or injuries.
  6. Ensure that there is adequate ventilation in the area where you are installing the venting system. Proper ventilation prevents the buildup of harmful gases, such as carbon monoxide, which can be dangerous if not properly vented.
  7. If you are unfamiliar with the installation process or uncertain about any steps, it is always advisable to consult with a professional plumber or HVAC technician who has experience in installing tankless water heaters.

Common challenges and troubleshooting tips

  • If you notice that your tankless water heater is not producing hot water or experiencing reduced water flow, it could be due to a venting issue. Here are some common challenges and troubleshooting tips:
  1. Vent blockage: Check for any obstructions in the vent pipe, such as debris, bird nests, or ice buildup. Clear any blockages to ensure proper exhaust flow.
  2. Vent length: The length of the venting system can affect the performance of your tankless water heater. Ensure that the vent pipe is within the manufacturer’s recommended limits. Excessive vent length can cause back pressure and impact the unit’s efficiency.
  3. Proper slope: Make sure that the vent pipe has a gradual slope towards the outside to prevent condensation buildup and potential damage to your tankless water heater.
  4. Vent size: Confirm that the diameter of the PVC pipe used for venting meets the requirements specified by the manufacturer. Using an undersized or oversized vent pipe can lead to poor combustion and improper ventilation.
  5. Combustion air supply: Insufficient air supply can cause ventilation issues with your tankless water heater. Check if there are any blockages or restrictions in the air intake vents and clear them if necessary.
  6. Condensation drain: Tankless water heaters produce condensate during operation, which needs to be properly drained away. Verify that the condensate drain line is free from obstructions and draining correctly.
  7. Joint sealant: Ensure that all joints in the PVC venting system are properly sealed using high-temperature silicone sealant or approved adhesive tape to prevent leaks.
  8. Professional inspection: If you’ve tried troubleshooting these common issues without success or if you’re unsure about any aspect of your tankless water heater’s venting system, it’s recommended to consult a professional HVAC technician for a thorough inspection and resolution of any underlying problems.

Remember, proper venting is crucial for the safe and efficient operation of your tankless water heater. Following these troubleshooting tips can help you identify and resolve common venting challenges. If in doubt, always refer to the manufacturer’s guidelines or seek professional assistance to ensure a reliable and well-functioning system.

Advantages and Considerations of PVC Venting Of Tankless Water Heater

PVC venting for tankless water heaters offers several advantages, including cost-effectiveness, easy installation, and compatibility with different models. It is a durable and long-lasting option that provides rust-resistant venting for optimal performance.


Using PVC venting for a tankless water heater offers significant cost-effectiveness benefits. PVC piping is generally more affordable compared to other materials like galvanized steel, making it a budget-friendly option for venting purposes.

Additionally, PVC pipes are readily available in most hardware stores, ensuring easy accessibility and eliminating the need for special or expensive materials.

Moreover, PVC venting installation is relatively simple and straightforward, which can save homeowners both time and money on professional installation services. The lightweight nature of PVC makes it easier to handle during the installation process as well.

Furthermore, PVC pipes have proven durability and longevity when used for venting tankless water heaters. They are resistant to rust and corrosion, ensuring that the venting system remains intact over an extended period without compromising its performance.

Easy installation

Installing a venting system for your tankless water heater can often be a complex and time-consuming task, especially if you’re unfamiliar with the process. However, when it comes to PVC venting, you’ll be pleased to know that it offers an easy and straightforward installation experience.

PVC piping is lightweight, flexible, and can be easily cut and connected using common household tools. This means that even as a novice homeowner, you won’t have to worry about complicated procedures or expensive professional assistance.

With the right materials and a willingness to learn, you can confidently tackle the installation of PVC venting for your tankless water heater on your own.

Durability and longevity

One of the key advantages of using PVC venting for your tankless water heater is its durability and longevity. PVC pipes are highly resistant to rust, corrosion, and wear, ensuring that they will last for many years without requiring frequent replacements.

Unlike metal venting options, PVC doesn’t deteriorate over time due to moisture or condensation from the exhaust gases. This means you can rely on your PVC vents to perform consistently well, providing reliable ventilation for your tankless water heater without worrying about costly repairs or replacements in the future.

With proper installation and maintenance, PVC venting can be a long-term solution that ensures optimal performance and efficiency of your tankless water heater system.

Compatibility with different tankless water heater models

Different tankless water heater models may have specific venting requirements and guidelines. It is important to ensure that the PVC venting system you choose is compatible with your particular model.

For example, the Rinnai Sensei tankless water heater offers 14 possible venting configurations, allowing for greater flexibility in installation. PVC and CPVC piping can be used for venting this model, providing an affordable and durable solution.

However, it is crucial to consult the appliance manual or manufacturer’s instructions to determine the specific compatibility of your tankless water heater model with PVC venting. By ensuring compatibility, you can confidently install a PVC venting system that meets both safety standards and your tankless water heater’s unique requirements.

Frequently Asked Questions

1. Can I use PVC pipe for venting a tankless water heater?

Yes, PVC pipe can be used for venting a tankless water heater as long as it is the correct type and size specified by the manufacturer and local building codes.

2. What are the advantages of using PVC for venting a tankless water heater?

Using PVC for venting a tankless water heater offers several advantages, including its affordability, ease of installation, resistance to corrosion, and compatibility with high-efficiency condensing units.

3. Are there any special considerations when installing PVC venting for a tankless water heater?

Yes, it is important to follow the manufacturer’s guidelines and local building codes when installing PVC venting for a tankless water heater. Proper sizing, slope, support, and sealing techniques must be employed to ensure safe and efficient operation.

4. Can I connect multiple appliances to the same PVC vent system?

In some cases, multiple appliances may be connected to the same PVC vent system if allowed by local building codes and approved by the manufacturer. However, proper sizing and consideration of each appliance’s requirements are necessary to maintain proper ventilation performance. It is recommended to consult with an HVAC professional or plumber experienced in handling such installations.


In conclusion, properly venting a tankless water heater is crucial for its efficient and safe operation. PVC venting offers numerous advantages, such as cost-effectiveness, easy installation, durability, and compatibility with different models.

By following the step-by-step guide in this comprehensive guide and considering the important factors outlined here, homeowners can confidently install their tankless water heaters with PVC venting for optimal performance.

Happy venting!

About the author

Debarghya Roy: A heating systems author, Passionate about energy efficiency and sustainability, Sharing insights and empowering readers through informative blog articles.