Choosing the right vent kit is critical for safe performance, proper exhaust flow, and a clean installation. The best option depends on your heater type, vent configuration, and wall-thickness limits.
This roundup of vertical tankless water heater vent kits focuses on compatibility, vent style, and installation practicality so you can narrow your choice faster.
Best 10 Vertical Tankless Water Heater Vent Kits Picks for 2026
Vertical Concentric Roof Kit
- Fits 3 in. x 5 in. concentric vent
- Includes flashing, caps, and storm collar
- Galvanized and stainless steel finish
Best For: Rheem non-condensing tankless heaters needing a vertical roof termination
Universal Horizontal Termination
- For compatible Rinnai non-condensing systems
- Weather-resistant plastic design
- 11-1/2 inch compact termination
Best For: Exterior wall termination on compatible Rinnai tankless water heaters
3-Inch Concentric Vent Kit
- 3-inch concentric PVC vent kit
- Includes all fittings for installation
- Supports horizontal or vertical install
Best For: High-efficiency tankless systems needing a flexible concentric vent solution
Concentric Horizontal Termination
- Direct replacement for Rheem, Ruud, Richmond
- Fits 3 in. / 5 in. concentric venting
- For walls up to 5 inches thick
Best For: OEM horizontal termination for compatible Rheem-family tankless heaters
Rinnai Termination Kit
8.7" Long Horizontal Termination Kit
- Condensing compatible for Rinnai units
- Stainless steel construction
- Indoor wall-mounted termination kit
Best For: Rinnai condensing tankless water heaters needing a wall termination
DiversiTech Vent Kit
2-Inch Horizontal Vent Termination Kit
- Fits high-efficiency fossil fuel appliances
- Includes all fittings for installation
- Supports horizontal or vertical installs
Best For: Versatile vent termination on tankless water heaters and furnaces
Rheem ProTech Vent Kit
Concentric Vertical Termination Kit
- For Rheem non-condensing tankless units
- Stainless steel with leak-proof gasket
- 3-inch inner and 5-inch outer vent
Best For: Rheem non-condensing tankless water heaters needing roof termination
OEM Factory Parts
Rheem ProTech Horizontal Vent Cone Kit
- OEM genuine factory authorized parts
- Snap-lock design helps create a leak-free connection
- Built with rugged metal construction
Best For: Rheem tankless owners who want a factory-authorized vent kit for a specific wall setup
Rheem Mid-Efficiency Build
RTG20280-1 Horizontal Vent Termination Kit
- Stainless steel construction resists corrosion
- Includes 12-inch wall plate and mounting screws
- Fits walls up to 10 inches thick
Best For: Rheem EcoSense mid-efficiency installs that need a durable kit for thicker walls
Vertical Concentric Roof Kit – Rheem ProTech RTG20282
If you need vertical tankless water heater vent kits for a Rheem-compatible non-condensing setup, the Rheem ProTech RTG20282 is built as a vertical concentric termination solution. It is intended for 3 in. x 5 in. concentric venting and includes the key exterior components needed to finish the roof termination, with a galvanized and stainless steel finish for the vent cap assembly.
Best For: Rheem tankless gas non-condensing water heaters that need a vertical concentric roof termination kit.
Pros:
- Fits 3 in. x 5 in. concentric vent systems
- Includes flashing, caps, and storm collar
- Galvanized and stainless steel finish
- OEM-style kit from Rheem ProTech
Cons:
- Add vent pipe to complete installation
- Designed for natural gas, non-condensing systems only
This is a practical pick when you want a matched vertical termination kit with the core roof penetration parts included. It is best viewed as a finishing component for an approved vent run rather than a full venting package.
Universal Horizontal Termination – Rinnai 223181 Horizontal Kit
Rinnai 223181 11-1/2” Universal Non-Condensing Plastic Horizontal Termination Ki, N/A
Check Price On AmazonFor vertical tankless water heater vent kits searches that also cover exterior terminations, the Rinnai 223181 is a horizontal termination kit made for compatible non-condensing tankless systems. It mounts to the wall where the vent exits, helping direct exhaust safely away from the structure while offering a weather-resistant plastic exterior finish.
Best For: Rinnai non-condensing tankless water heaters that need a simple horizontal wall termination.
Pros:
- Designed for compatible Rinnai non-condensing vent systems
- Weather-resistant plastic construction
- Helps direct exhaust away from the building
- Compact 11-1/2 inch exterior profile
Cons:
- Horizontal termination only
- Compatibility depends on approved venting systems
This kit makes sense if you need a straightforward exterior wall cap for a matching Rinnai setup. Its compact, corrosion-resistant design is aimed at tidy termination rather than full vent routing.
3-Inch Concentric Vent Kit – DiversiTech CVENT-3
If you are comparing vertical tankless water heater vent kits for a high-efficiency appliance, the DiversiTech CVENT-3 offers a 3-inch concentric PVC termination solution. It is designed for tankless gas water heaters and high-efficiency furnaces, with included fittings for both horizontal through-wall and vertical through-roof installation.
Best For: High-efficiency tankless gas water heaters or furnaces that need a complete concentric vent kit.
Pros:
- 3-inch concentric vent design
- Includes all fittings for installation
- Works for horizontal or vertical installations
- Low-profile appearance conceals intake and exhaust piping
Cons:
- PVC construction may not suit every application
- Heavier and larger than a simple termination cap
This is the most flexible option in the group if you need one kit that can support either wall or roof termination. Its all-in-one approach is useful when you want a cleaner exterior look and fewer separate parts.
Concentric Horizontal Termination – Rheem ProTech RTG20274A
For buyers looking at vertical tankless water heater vent kits and related termination parts, the Rheem ProTech RTG20274A is a concentric direct vent horizontal termination kit. It is a genuine Rheem, Ruud, and Richmond replacement part for 3 in. / 5 in. venting and is rated for use on walls up to 5 inches thick.
Best For: Rheem, Ruud, or Richmond tankless water heaters needing an OEM horizontal wall termination.
Pros:
- Direct replacement for Rheem, Ruud, and Richmond water heaters
- Fits concentric 3 in. / 5 in. venting
- Works on walls up to 5 inches thick
- OEM genuine factory authorized part
Cons:
- Horizontal termination only
- Additional venting is required to complete installation
This is a solid choice when you want a factory-authorized termination component that matches an existing compatible heater. It is a specialized part, so it works best as part of a broader approved venting setup.
Rinnai Termination Kit – 8.7" Long Horizontal Termination Kit
If you need vertical tankless water heater vent kits for a condensing Rinnai setup, this horizontal termination kit is built for indoor wall installation and includes stainless steel construction for a more durable venting finish. Its compact 8.7-inch length makes it a straightforward option when you’re matching a Rinnai condensing system to the right termination hardware.
Best For: Rinnai condensing tankless water heater owners who need a wall-mounted termination kit.
Pros:
- Designed for condensing compatible applications
- Stainless steel construction
- Indoor installation with wall mount type
- Limited lifetime warranty
Cons:
- Made specifically for Rinnai systems
- Horizontal termination format may not fit every vent layout
This is a purpose-built termination kit with clear compatibility focus, so it makes sense when you want the right factory-style parts rather than a generic workaround. If your installation matches the Rinnai condensing spec, it’s a clean, durable pick.
DiversiTech Vent Kit – 2-Inch Horizontal Vent Termination Kit
For vertical tankless water heater vent kits and other high-efficiency appliances, this DiversiTech termination kit is a practical all-in-one option that supports both horizontal and vertical installations. The low-profile design is meant to conceal intake and exhaust pipework, which can help the outside finish look cleaner while still supporting proper venting.
Best For: High-efficiency tankless water heaters and furnaces that need a versatile vent termination kit.
Pros:
- Suitable for high-efficiency fossil fuel appliances
- Includes all fittings needed for installation
- Low-profile design helps conceal pipework
- Works for horizontal and vertical installations
Cons:
- Generic fit may not suit every appliance model
- Dimensions may require careful planning before install
This kit stands out for flexibility and convenience, especially if you want one product that can handle different vent routing needs. It’s a solid choice when clean appearance and complete fittings matter as much as proper termination.
Rheem ProTech Vent Kit – Concentric Vertical Termination Kit
If you’re shopping vertical tankless water heater vent kits for a Rheem non-condensing unit, this concentric termination kit is designed specifically for that job. It uses stainless steel construction, a seamless precision-formed gasket, and concentric 3-inch inner and 5-inch outer venting to support a neat roof termination setup.
Best For: Rheem non-condensing tankless water heaters that need a concentric vertical roof termination.
Pros:
- Built for Rheem tankless non-condensing water heaters
- Concentric vertical termination design
- Stainless steel construction
- Leak-proof seamless gasket and included hardware/instructions
Cons:
- Model-specific compatibility limits use outside Rheem systems
- Not intended for electric units
This is a focused, model-specific venting solution that should appeal to buyers who want the right Rheem termination parts for a roof exit. The construction and included installation pieces make it a strong match for a cleaner, more direct install.
Low-Profile Universal Fit – SP20285 Horizontal Vent Termination Kit
If you need vertical tankless water heater vent kits that can also handle through-the-wall routing, this SP20285 kit is built around a flexible horizontal/vertical installation setup. It is designed for 2-inch PVC and ABS pipe, with a low-profile cover that helps conceal intake and exhaust pipework for a cleaner exterior finish.
Best For: Buyers looking for a compact, economical vent termination kit for 2-inch tankless or high-efficiency appliances with a cleaner outside-wall appearance.
Pros:
- Flexible for both horizontal and vertical installations
- Low-profile design helps hide exposed intake and exhaust pipes
- Includes screws for a simple package with no extra outside fittings needed
- Suitable for tankless water heaters, furnaces, and other high-efficiency fossil fuel appliances
Cons:
- Only fits 2-inch PVC and ABS pipes
- Requires careful cut dimensions for proper installation
- Best suited to buyers who have already confirmed pipe sizing
Overall, this is a practical option if you want a vent termination kit that prioritizes a neat exterior and broad installation flexibility, as long as your system uses 2-inch pipe. The key is confirming dimensions before ordering, since the fit requirements are specific.
OEM Factory Parts – Rheem ProTech Horizontal Vent Cone Kit
For homeowners comparing vertical tankless water heater vent kits and related through-the-wall options, this Rheem ProTech kit is a brand-specific choice for non-condensing tankless units. It uses a snap-lock design for leak-free connection and comes with rugged metal construction, making it a straightforward pick when you want OEM parts and simple installation support.
Best For: Rheem owners who want a factory-authorized vent termination kit with durable metal construction and a leak-free connection design.
Pros:
- OEM genuine factory authorized parts
- Exclusive snap-lock design for leak-free connection
- Rugged metal construction for added durability
- Includes hardware and instructions when applicable
Cons:
- Made for Rheem non-condensing tankless water heaters only
- Wall opening is specific to 2 in. x 6 in. walls
- Not a universal fit for mixed-brand installations
This kit makes the most sense if you want to stay with OEM components and avoid compatibility guesswork. Its main advantage is fit confidence for the right Rheem setup, rather than broad cross-brand flexibility.
Rheem Mid-Efficiency Build – RTG20280-1 Horizontal Vent Termination Kit
If you need vertical tankless water heater vent kits with a focus on durable through-the-wall parts, this Rheem RTG20280-1 kit is built for EcoSense mid-efficiency tankless gas indoor direct vent units. It includes stainless steel components, a 12-inch wall plate, and a 94-degree elbow, plus adjustability for walls up to 10 inches thick.
Best For: Rheem EcoSense owners who need a stainless steel horizontal vent termination kit for thicker walls and non-condensing units.
Pros:
- Stainless steel construction for corrosion resistance
- Includes a complete wall plate assembly with mounting screws
- 94-degree elbow helps support proper venting configuration
- Can be extended for wall thicknesses up to 10 inches
Cons:
- Designed specifically for Rheem EcoSense mid-efficiency indoor direct vent units
- Not intended as a universal kit for all tankless heaters
- Horizontal vent dimensions are tied to 3 x 5 inch sizing
For the right Rheem system, this kit offers a strong mix of durability and installation flexibility. The adjustable wall thickness and included hardware are especially useful if your vent path has a thicker exterior wall to clear.
How We Picked These Vertical Tankless Water Heater Vent Kits
We prioritized fit, vent type, build quality, and install flexibility. That means checking whether a kit is designed for condensing or non-condensing units, whether it supports vertical or horizontal termination, and whether the dimensions match the wall or roof penetration you need.
We also considered brand compatibility, since many tankless systems require manufacturer-specific parts for safe operation and warranty protection.
Quick Comparison
In this group, some kits are made for vertical termination on non-condensing units, while others are concentric or horizontal options that may be useful depending on your layout. If your installation calls for vertical exhaust routing, make sure the exact vent path and termination style match the heater manual before buying.
For many shoppers, the biggest differences come down to diameter, maximum wall thickness, and whether the kit is intended for direct vent use. Those details matter more than appearance or included hardware.
Key Buying Factors for Vertical Tankless Water Heater Vent Kits
Vent Type and Heater Compatibility
Start with the water heater manual. Vertical Tankless Water Heater Vent Kits are not universal, and condensing and non-condensing models often require different materials and termination designs. A wrong match can create performance issues or fail inspection.
Vertical Vs. Horizontal Termination
Even if a product is labeled as a vent kit, confirm whether it is meant for vertical termination, horizontal termination, or a concentric direct-vent setup. The installation route should be planned first, then the kit selected to fit it.
Dimensions and Wall Thickness
Check pipe diameter, termination length, and maximum wall thickness. These measurements affect whether the kit will clear siding, masonry, or framing without modifications. A few inches can make the difference between a clean install and a return.
Materials and Weather Resistance
Look for corrosion-resistant construction, secure seals, and hardware suited to outdoor exposure. Vent terminations need to handle heat, condensate, and weather over time.
Who Should Buy Which Vertical Tankless Water Heater Vent Kits?
Choose a brand-specific kit if you want the safest path for a matching Rheem or Rinnai system. Choose a concentric kit if your installation needs coordinated intake and exhaust through one opening. Choose a horizontal termination kit if your wall layout is fixed and the manual allows sidewall venting. If you are unsure, verify the heater model, vent class, and local code requirements before ordering.
The best Vertical Tankless Water Heater Vent Kits are the ones that match the appliance exactly, fit the wall or roof opening cleanly, and simplify installation without compromising safety.
