Answering the question of how to vent a tankless water heater safely and efficiently, this guide highlights five venting options and kits. The selections favor ease of installation, corrosion resistance, and durable construction. Best for homeowners upgrading from tank systems, new installations, or those seeking safer venting configurations that simplify maintenance and reduce leaks. The top choices cover concentric vent pipes, horizontal termination kits, stainless steel vent components, and complete venting kits for DIY or professional installs. Use the buying table and guide to compare features and decide which setup fits your home.
| Product | Key Benefit | Best For |
|---|---|---|
| Rheem RTG20270D Tankless 36 in. Concentric Vent Pipe | Easy one-step connection, leak-proof gasket, durable stainless steel | Quick installs, reliable venting |
| Rheem RTG20280-1 Tankless Horizontal Vent Termination Kit | Complete wall plate, durable materials, 94° elbow for proper venting | Wall-mounted venting with secure finish |
| GASLAND 3″ Stainless Steel Vent Pipe Kit for Gas Tankless Water Heaters | T304 stainless steel, modular lengths, termination hood | Flexible horizontal venting solutions |
| MIZUDO Natural Gas Tankless Water Heater Venting (implied kit) | High BTU for whole-home hot water, precise temp control | High-demand households needing stable output |
| 3″ OD Stainless Steel Water Heater Vent Pipe Kit | Includes elbow and pipe, compatible with standard 3″ vent systems | Complete DIY venting bundles |
Rheem RTG20270D Concentric Vent Pipe
Best for quick, hassle-free installation. The 36-inch concentric vent pipe uses a one-step connection system and features a gasket-sealed, leak-proof design. Made with stainless steel for long-lasting durability, this kit reduces installation complexity and helps ensure secure venting for compliant operation. Suitable for home upgrades and new tankless setups that prioritize straightforward vent routing. Limitation: designed to be paired with compatible Rheem units; verify fit before purchasing.
Rheem RTG20280-1 Horizontal Vent Termination Kit
Best for wall-mounted configurations needing a complete termination assembly. This kit includes robust stainless steel components and a 12-inch wall plate with mounting screws for secure installation. The included 94-degree angled elbow helps ensure the vent exits cleanly and safely. Choose this if your installation requires a secure wall termination with a clean exterior finish. Caution: confirm clearance around the termination to avoid obstruction or wind exposure issues.
GASLAND 3″ Stainless Vent Pipe Kit
Best for modular, easy-to-install venting. The kit uses T304 stainless steel for corrosion and temperature resistance, includes a 3″ termination hood and elbow, and can be assembled to fit different run lengths. This is ideal for homeowners who want a durable, corrosion-resistant venting solution with configurable length. Limitation: ensure the kit’s length options match the installation path to avoid gaps or overhangs.
MIZUDO 199,000 BTU Tankless Venting
Best for high-demand, whole-home hot water. This system supports up to 10.3 GPM with precise ±1°F temperature stability, suitable for multiple bathrooms and heavy-duty cycles. Best for larger homes or busy households where consistent hot water matters. Limitations: temperature control relies on the unit’s modulation and may be affected by long vent runs or external conditions; verify vent sizing and clearance for indoor installation.
3″ OD Stainless Vent Pipe Kit
Best for ready-to-assemble venting bundles. This kit includes a 3″ vent elbow and a 3″ OD horizontal pipe, designed for compatibility with standard 3″ vent systems. It’s suitable for DIY installers or professionals needing a straightforward venting bundle. Caution: measure existing vent diameter to ensure compatibility before purchasing.
Buying Guide: Key Considerations for Tankless Venting
Vent type and compatibility: Check whether your unit requires concentric, horizontal, or standard venting. Confirm the vent diameter, elbow angles, and wall termination requirements for outdoor clearance and wind exposure.
Material and durability: Stainless steel options (especially T304) resist corrosion and high temperatures, extending vent life and reducing maintenance. Material choice matters in coastal or humid environments.
Installation complexity: Some kits offer a one-step connection or preassembled wall plates, which can speed up installation. DIY-friendly bundles are useful for simple runs, while professional installs may be needed for long or complex vent paths.
Temperature and safety features: Ensure the venting kit aligns with your heater’s BTU rating and venting capacity. Adequate venting reduces backdraft risk and ensures safe combustion exhaust removal.
Maintenance and future-proofing: Choose modular components that can be replaced or extended if you upgrade heaters. Durable gaskets and leak-proof fittings reduce long-term maintenance needs.
Frequently Asked Questions
- What venting material is best for tankless water heaters? Stainless steel (often 304-grade) is preferred for its corrosion resistance and durability in high-temperature exhaust.
- Can I install venting kits myself? Some kits are DIY-friendly with simple connections, but long or complex vent runs may require a licensed professional.
- Do concentric vents differ from standard horizontal vents? Yes. Concentric vents combine exhaust and intake in one pipe, offering a compact option, while horizontal vents route exhaust separately to the exterior.
- How do I know if a vent kit fits my tankless unit? Check the unit’s vent diameter, required elbow angles, and compatibility notes from the manufacturer.
- What maintenance is needed for venting systems? Inspect for corrosion, loose fittings, and gasket integrity periodically, especially after severe weather or heating seasons.
- Is venting size related to heating capacity? Yes. Higher BTU units may require larger or longer vent runs; verify with the installation instructions.