Choosing the right venting hardware matters as much as choosing the water heater itself. The wrong fit can create installation delays, poor performance, or unsafe exhaust routing.
This roundup of the best horizontal vent kit for tankless water heater options focuses on compatibility, build quality, and ease of installation so you can narrow down the right match faster.
Best 10 Horizontal Vent Kit for Tankless Water Heater Picks for 2026
Best for Clean Through-Wall Termination
DiversiTech HVENT2 2-Inch Horizontal Vent Kit
- All-in-one termination kit for easier installation
- Low-profile look conceals intake and exhaust pipes
- Works for tankless water heaters and high-efficiency furnaces
Best For: Installers and homeowners who want a tidy, through-wall vent termination for tankless water heaters.
Best for Easy Horizontal Runs
CAMPLUX 3" Stainless Z-Vent Kit
- Includes the main parts for a horizontal vent run
- Adjustable thimble suits thicker walls
- Stainless steel build resists corrosion
Best For: Installers and homeowners needing a complete 3-inch horizontal venting kit for compatible tankless water heaters.
Best for OEM Fit
Rheem ProTech Horizontal Vent Cone Kit
- OEM Genuine Factory Authorized Parts
- Rugged metal construction
- Easy installation for compatible wall terminations
Best For: Rheem owners and installers needing a compatible OEM vent termination kit for non-condensing tankless units.
Best for Easy Setup
3" Stainless Steel Tankless Vent Kit
- Includes a horizontal termination pipe and elbow
- 3-inch OD sizing suits many compatible systems
- Stainless steel build is made for heat and durability
Best For: DIYers and installers needing a simple 3-inch horizontal venting solution for compatible tankless water heaters.
Best for 2-Inch Pipe Replacements
SP20285 Horizontal Vent Termination Kit
- Fits 2-inch PVC and ABS vent piping
- Improves exterior appearance over exposed pipes
- Includes screws for outside-wall termination
Best For: Installers or homeowners with 2-inch vent piping who want a cleaner exterior finish.
Best for Easy Horizontal Install
FOGATTI Stainless Steel Vent Kit
- T304 stainless steel resists corrosion and heat.
- Easy elbow-and-pipe assembly for DIY installs.
- Made for horizontal venting on gas tankless heaters.
Best For: DIYers who want a durable, simple horizontal venting kit for a compatible gas tankless water heater.
Best for Rheem Direct-Vent Installations
Rheem RTG20280-1 Horizontal Vent Kit
- Stainless steel build resists corrosion
- Includes wall plate, screws, and 94° elbow
- Fits wall thicknesses up to 10 inches
Best For: Rheem non-condensing tankless gas units needing a horizontal through-the-wall vent termination.
Best OEM Match
Rheem ProTech Horizontal Vent Cone Kit
- OEM factory-authorized replacement
- Fits Rheem, Ruud, and Richmond heaters
- Supports walls up to 10 inches
Best For: Compatible tankless gas heater owners who want a direct-fit factory replacement.
Best for Clean Through-Wall Termination – DiversiTech HVENT2 2-Inch Horizontal Vent Kit
If you need a horizontal vent kit for tankless water heater installations, the DiversiTech HVENT2 is built to keep high-efficiency venting neat, direct, and code-friendly. It covers both intake and exhaust terminations and is sized for residential use, making it a practical choice for a clean through-wall finish.
Best For: Homeowners and installers who want an all-in-one horizontal termination kit for tankless water heaters or other high-efficiency gas appliances.
Pros:
- Includes the fittings needed for a simpler outside connection
- Low-profile design helps conceal intake and exhaust piping
- Works with horizontal through-the-wall and vertical through-the-roof setups
- Suitable for tankless water heaters and high-efficiency furnaces
Cons:
- Specific fitment depends on your appliance and venting requirements
- 2-inch size may not match every system
- Installation still requires proper venting knowledge and compliance checks
Overall, this is a solid horizontal vent kit for tankless water heater projects where appearance and straightforward termination matter. It is especially appealing if you want a tidy exterior finish without sourcing extra outside fittings.
Best for Easy Horizontal Runs – CAMPLUX 3" Stainless Z-Vent Kit
If you need a horizontal vent kit for tankless water heater installations, this CAMPLUX kit covers the basics in one package. It includes the termination hood, wall thimble, 90° elbow, and vent pipe sections needed for a clean horizontal exhaust path, with a 3-inch diameter that matches many CAMPLUX and Thermomate units.
Best For: Homeowners or installers who want a complete 3-inch horizontal venting solution for compatible indoor gas tankless water heaters.
Pros:
- Complete kit with termination hood, wall thimble, elbow, and vent pipe
- Adjustable wall thimble fits wall thicknesses from 3.9" to 7.8"
- Stainless steel construction helps resist corrosion and is easy to clean
- Low-resistance design helps exhaust flue gases while limiting debris and rain entry
Cons:
- Only fits 3-inch venting setups, so compatibility is limited
- Primarily aimed at specific CAMPLUX and Thermomate models
- May still require careful measurement for a proper horizontal run
Overall, this is a practical horizontal vent kit for tankless water heater projects when you want a bundled, stainless-steel setup instead of sourcing each part separately. Its strength is convenience and fit flexibility, but buyers should verify diameter and model compatibility before ordering.
Best for OEM Fit – Rheem ProTech Horizontal Vent Cone Kit
If you need a horizontal vent kit for tankless water heater setups that stays true to the original equipment design, this Rheem ProTech kit is built for compatible non-condensing models and simple wall termination installs. The rugged metal construction and included OEM parts make it a practical choice when you want a straightforward replacement or new install with fewer compatibility worries.
Best For: Rheem owners or installers who want an OEM horizontal vent termination kit for a 2 in. x 6 in. wall.
Pros:
- OEM Genuine Factory Authorized Parts for better compatibility
- Rugged metal construction adds durability
- Designed for easy installation in a horizontal wall termination
- Backed by a 1-year limited warranty
Cons:
- Made for specific Rheem tankless non-condensing heaters only
- Not a universal vent kit for all brands or models
- May be more than needed for basic replacement jobs
Overall, this is a solid horizontal vent kit for tankless water heater buyers who prioritize OEM fit, durable construction, and a cleaner install path over bargain pricing. If your system matches the spec, it’s a dependable, purpose-built option.
Best for Easy Setup – 3" Stainless Steel Tankless Vent Kit
If you need a straightforward horizontal vent kit for tankless water heater installs, this stainless steel set covers the basics without extra parts to sort through. It includes a horizontal termination pipe and an elbow in the common 3-inch size, making it a practical choice for compatible indoor gas units and quick replacement jobs.
Best For: DIYers, installers, and homeowners who want a simple 3-inch horizontal venting solution for compatible tankless water heaters.
Pros:
- Includes the key vent pieces needed for a basic horizontal termination setup
- 3-inch OD sizing fits many compatible tankless water heater systems
- Stainless steel construction adds durability and heat resistance
- Crimped end design helps make installation more convenient
Cons:
- Only works with systems that use a 3-inch vent diameter
- Does not include a full multi-piece vent run or extra accessories
- Fitment should be confirmed before purchase
This horizontal vent kit for tankless water heater setups is a solid pick when you want a simple, durable, and standard-size termination solution rather than a more complex bundled system. Just verify your vent diameter and model compatibility before buying.
Best for 2-Inch Pipe Replacements – SP20285 Horizontal Vent Termination Kit
If you need a horizontal vent kit for tankless water heater installs using 2-inch PVC or ABS, the SP20285 is a straightforward option for terminating venting through an exterior wall. It is designed to improve vent performance while also cleaning up the look of exposed piping on the outside of the home.
Best For: Homeowners or installers replacing or finishing a 2-inch horizontal vent setup where a neat exterior appearance and proper sealing matter.
Pros:
- Fits 2-inch PVC and ABS piping, making it a targeted match for many tankless systems
- Helps improve exterior appearance compared with exposed vent pipes
- Can be painted to better blend with the home’s exterior
- Includes screws and is built for outside-wall termination
Cons:
- Only works with 2-inch piping, so compatibility must be checked first
- Installation may require trimming pipe length for proper fit
- Silicone sealing is recommended for best results, so extra materials may be needed
This horizontal vent kit for tankless water heater use is most appealing when you already know your pipe size and want a cleaner, more finished exterior termination. It is less of a universal pick and more of a practical fit-first solution for 2-inch installs.
Best for Easy Horizontal Install – FOGATTI Stainless Steel Vent Kit
If you need a straightforward horizontal vent kit for tankless water heater installations, this FOGATTI kit is built to move exhaust safely and efficiently while keeping the setup simple. The T304 stainless steel construction is a practical plus for corrosion resistance and high-temperature durability.
Best For: DIYers and homeowners who want a durable, easy-to-install venting solution for a gas tankless water heater.
Pros:
- T304 stainless steel helps resist corrosion and heat over time.
- Simple elbow-and-pipe assembly makes installation more approachable.
- Designed for horizontal exhaust on gas tankless water heaters.
- Includes the core pieces needed for a basic venting setup.
Cons:
- Diameter must match your specific heater and vent requirements.
- May need additional components for more complex vent runs.
- Primarily suited to horizontal termination applications.
As a horizontal vent kit for tankless water heater use, this FOGATTI option stands out for its durable stainless build and low-fuss assembly. It’s a solid fit if you want a dependable, no-nonsense venting kit for a compatible gas unit.
Best for 2-Inch Pipes – SP20285 Horizontal Vent Kit
If you need a horizontal vent kit for tankless water heater installations and already know you’re working with 2-inch piping, the SP20285 is a straightforward option to consider. It’s designed for high-efficiency gas appliances, includes the needed screws, and mounts flush to an outside wall for a cleaner finish.
Best For: Homeowners or installers who need a compact horizontal termination kit for 2-inch PVC or ABS tankless water heater venting.
Pros:
- Fits 2-inch PVC and ABS piping for compatible tankless setups
- Includes screws and vent termination hardware for easier installation
- Flush outside-wall design helps keep the exterior look tidy
- Works with high-efficiency gas water heaters and furnaces
Cons:
- Only suitable for 2-inch pipe systems, so sizing must be verified first
- Intake and exhaust pipes are sold separately
This is a practical pick if compatibility is the top priority in a horizontal vent kit for tankless water heater project. It’s not the most versatile option, but for the right 2-inch install, it covers the essentials without extra parts or a complicated setup.
Best for Rheem Direct-Vent Installations – Rheem RTG20280-1 Horizontal Vent Kit
If you need a horizontal vent kit for tankless water heater installations on a Rheem EcoSense indoor direct-vent unit, this ProTech kit is built for the job. It uses stainless steel components, a 3 x 5 inch vent profile, and includes the hardware needed for a through-the-wall termination.
Best For: Homeowners and installers working with Rheem non-condensing tankless gas units that need a sturdy horizontal through-the-wall vent solution.
Pros:
- Stainless steel construction for corrosion resistance and long-term durability
- Includes a 12-inch wall plate, mounting screws, and a 94-degree elbow
- Adjustable to fit wall thicknesses up to 10 inches
- Designed specifically for Rheem EcoSense mid-efficiency indoor direct vent models
Cons:
- Only compatible with certain Rheem non-condensing tankless water heaters
- Not a universal vent kit for all brands or venting setups
- May be overkill if you need a basic or low-cost replacement part
Overall, this is a well-matched horizontal vent kit for tankless water heater jobs where fit, material quality, and wall-depth flexibility matter more than universal compatibility. If you’re installing a compatible Rheem unit, it’s a practical, purpose-built option.
Best for Flexible Installations – Thermomate 3" Stainless Horizontal Vent Kit
If you need a horizontal vent kit for tankless water heater installations, this Thermomate kit is a practical pick for standard 3-inch gas units. It includes the core parts needed for a horizontal exhaust run, and the detachable pieces make it easier to adapt the layout to your wall and clearance needs.
Best For: Homeowners and installers who want a universal 3-inch venting kit with corrosion-resistant stainless steel parts for indoor tankless water heater setups.
Pros:
- Universal 3-inch fit works with many gas tankless water heater brands
- Includes termination hood, 90° elbow, vent pipes, and wall thimble
- T304 stainless steel helps resist heat, rust, and exhaust corrosion
- Adjustable, detachable pieces support custom horizontal assembly
Cons:
- Only suitable for 3-inch systems, so sizing must match your heater
- Horizontal venting layout may still require careful measurement and planning
Overall, this is a solid horizontal vent kit for tankless water heater buyers who want a universal stainless-steel option with the essential parts in one box. It is especially appealing if you need a flexible kit for replacement or new indoor installation work.
Best OEM Match – Rheem ProTech Horizontal Vent Cone Kit
If you need a horizontal vent kit for tankless water heater installations and want a factory-correct part, this Rheem ProTech kit is built for direct replacement use with Rheem, Ruud, and Richmond non-condensing units. It’s intended to help finish a safe horizontal vent run while keeping the exterior termination neat and professional.
Best For: Owners and installers looking for an OEM vent termination kit that matches compatible Rheem-family tankless gas heaters.
Pros:
- OEM genuine factory-authorized part for compatible systems
- Direct replacement for Rheem, Ruud, and Richmond water heaters
- Works with additional venting to complete the installation
- Designed for walls up to 10 inches thick
Cons:
- Only suited to compatible non-condensing gas models
- Not a complete vent system on its own
- May require careful planning for wall depth and elbow routing
As a horizontal vent kit for tankless water heater setups, this is a strong choice when you want the safest route is also the simplest: use the OEM part that’s made for the job. It’s especially appealing for replacements where fit, finish, and compatibility matter more than saving a few dollars.
How We Picked the Best Horizontal Vent Kit for Tankless Water Heater
For this roundup, we focused on Horizontal Vent Kit for Tankless Water Heater options that are commonly used with gas tankless systems and related high-efficiency appliances. Priority went to kits with clear sizing, durable metal construction, complete accessory bundles, and strong compatibility notes for non-condensing or universal applications.
We also looked at wall-thickness support, termination design, and whether the kit includes essentials like elbows, thimbles, screws, or caps. Those details often determine whether a kit is truly install-ready or needs extra parts.
Quick Comparison
Most shoppers will notice three main differences: vent diameter, wall depth range, and material. Two-inch kits are typically tied to specific non-condensing systems, while 3-inch stainless steel kits offer broader compatibility in many setups. Some products are purpose-built for a narrow wall range, while others are more flexible for different install conditions.
If you are replacing an existing setup, match the vent size and heater model first, then check whether the termination style and included hardware line up with your routing plan.
Key Buying Factors for a Horizontal Vent Kit for Tankless Water Heater
Compatibility with Your Heater
Always verify whether the unit is designed for your exact brand, model, and venting type. Non-condensing tankless heaters often have stricter requirements than universal kits, and even a small mismatch can cause a failed install.
Vent Diameter and Wall Thickness
Measure the vent size and wall depth before ordering. A Horizontal Vent Kit for Tankless Water Heater must fit both the pipe diameter and the wall pass-through length without forcing awkward offsets or extensions.
Material and Corrosion Resistance
Stainless steel is a strong choice for durability and heat resistance. It is especially useful in systems exposed to moisture, condensate-adjacent conditions, or long-term outdoor termination exposure.
Included Parts
Check whether the kit includes a termination hood, elbow, wall thimble, screws, or rain cap. A more complete kit can save time and reduce the chance of missing a required component during installation.
Who Should Buy Which Horizontal Vent Kit for Tankless Water Heater?
If you want the safest path for a brand-specific replacement, choose the kit that matches your heater’s manufacturer guidance and vent size exactly. If you need more flexibility for a common retrofit, a universal stainless steel option may be the better fit.
For shorter installs or standard wall depths, a compact termination kit can be the simplest choice. For thicker walls or more complex routing, look for a product that clearly states wall-thickness compatibility and includes the needed transition pieces. In short: start with compatibility, then choose the most complete kit that meets your install conditions.
