The best 3×5 concentric vent pipe depends on the required length, termination style, and water-heater manufacturer. The Rheem ProTech adjustable kit is suited to buyers who need a configurable vent assembly, while DuraVent offers fixed-length pipe options for measured runs. The VATTCEEL kit is an option for shoppers seeking a short stainless-steel pipe and broad stated brand compatibility. Check the heater’s installation manual before choosing any vent component.
| Product | Best For | Key Detail |
|---|---|---|
| Rheem ProTech Adjustable Kit | Adjustable or cut-to-size installation | Stainless steel concentric vent |
| DuraVent 6-Inch Pipe | Short extensions | 3 x 5 inches |
| DuraVent 24-Inch Pipe | Medium fixed-length runs | 24-inch length |
| DuraVent 36-Inch Pipe | Longer fixed-length runs | 36-inch length |
| VATTCEEL 12-Inch Kit | Short stainless-steel sections | 304 stainless steel |
Rheem ProTech Adjustable Concentric Vent Kit
Best for: Buyers who need a Rheem ProTech concentric vent kit that can be adjusted or cut to fit the installation. The listing identifies stainless-steel construction and an adjustable design, making this a flexible choice compared with fixed-length pipe sections.
The product name describes a 21-to-35-inch kit, while its feature text gives a different adjustment description. Confirm the actual adjustment range and suitability with the manufacturer’s installation instructions before ordering. Choose this option when adjustability is important; avoid assuming its final length without checking the specifications.
DuraVent 6-Inch Concentric Vent Pipe
Best for: Installations that call for a short, fixed-length 3 x 5-inch pipe section. The listing identifies this as a DuraVent concentric vent component with a 6-inch length and part number 35CVS-06. Its compact length makes it a more targeted choice than a 24- or 36-inch section when the measured requirement is short.
The supplied product details do not specify connection requirements or which water-heater models it fits. Verify system compatibility and the required vent length before selecting it. This is not the best choice when a longer continuous section is needed.
DuraVent 24-Inch Concentric Vent Pipe
Best for: Buyers who have measured a 24-inch requirement and want a fixed-length 3 x 5-inch vent section. The listing states the size, length, and an easy in-and-out fit. It provides a middle-ground option between the 6-inch and 36-inch DuraVent pipes in this selection.
Choose this pipe when the specified run calls for its listed length. The product information does not provide a complete compatibility list, so confirm that the component is approved for the exact vent system and appliance. Avoid substituting it for a different length based only on appearance.
DuraVent 36-Inch Concentric Vent Pipe
Best for: Installations requiring a longer fixed-length section. This DuraVent pipe is listed as 3 x 5 inches and 36 inches long, with an easy in-and-out fit. Compared with the 24-inch model, it suits a longer measured run without relying on an adjustable section.
Its fixed length is also its main limitation: it may not suit a shorter space or a layout that requires a different component. The supplied details do not identify specific appliance compatibility. Check the heater manual and vent-system requirements before purchase.
VATTCEEL 12-Inch Stainless-Steel Vent Kit
Best for: Buyers seeking a 12-inch 3 x 5-inch straight pipe made from 304 stainless steel. The listing states compatibility with many gas tankless water heaters, including Rinnai, Navien, Rheem, and A.O. Smith. It also describes corrosion resistance, high-temperature tolerance, and UV protection.
The kit description identifies one straight pipe, not a complete collection of termination parts. Confirm what the installation requires and whether the stated compatibility applies to the exact model. Choose it for a short pipe section, not when a complete vent termination assembly is needed.
Buying Guide: Choosing A 3×5 Concentric Vent Pipe
What does 3×5 mean?
The 3 x 5-inch designation identifies the listed concentric vent size. The selected products vary in length and configuration, so matching the size alone is not enough. Check the appliance manual for approved vent type, component requirements, and installation limits before purchasing.
Should you choose a fixed or adjustable length?
Fixed lengths such as 6, 24, and 36 inches are straightforward to compare against a measured requirement. An adjustable or cut-to-size product may help with a variable layout, but confirm its actual range because product descriptions can contain inconsistent measurements. Do not cut or modify a component unless its instructions permit it.
Do you need a pipe or a termination kit?
A straight pipe section extends a vent run; a termination kit may include parts needed where the vent exits the building. These products are not interchangeable. For example, the VATTCEEL listing describes one straight pipe, while a termination assembly may include caps or flashing. Review the parts list and installation plan.
How should you check compatibility?
Use the exact water-heater model and the manufacturer’s venting instructions to verify the required components. A listing’s general brand compatibility statement does not establish fit for every model or installation. When details are unclear, confirm the part number with the manufacturer or a qualified installer.
Frequently Asked Questions
Can any 3×5 concentric vent pipe fit any tankless water heater?
No. Match the vent component to the appliance model and its installation instructions. The 3 x 5-inch size alone does not confirm compatibility.
What is the difference between concentric vent pipe lengths?
Length determines how much of the vent run a section covers. These listings include 6-, 12-, 24-, and 36-inch options, plus an adjustable Rheem kit.
Is a straight vent pipe the same as a vent termination kit?
No. A straight pipe is a section of vent, while a termination kit can include end or roof components. Check the listed contents before ordering.
What should I verify before installation?
Confirm appliance compatibility, vent size, required length, permitted components, and installation instructions. Use a qualified professional if the requirements are uncertain.