Answering common buyers’ questions, this guide highlights five top B-vent caps that fit 5″ to 9″ pipes and help prevent rain, debris, and animals from entering your vent while maintaining proper draft. The selections suit homeowners installing natural gas, LP appliances, or high-wind environments. Each product section explains who benefits most, why it’s a good pick, and any notable limitations.
| Product | Best For | Size Range | Key Benefit |
|---|---|---|---|
| Water-Tite 81695 Multi-Cap | Residential gas appliances, standard chimneys | 5″ – 7″ | Non-clogging draft design |
| SELKIRK CORP 106800 | Gas venting with gravity draft | 6″ | Top round design for gravity draft |
| DuraVent 4BVVTH | Vertical roof lines with wind concerns | 4″ | Improved wind performance |
| Simpson Dura-Vent 8GVVTH | Large-diameter venting | 8″ | High-wind cap for 8″ vents |
| Water-Tite 81696 Multi-Cap | Extended size range, 7″ to 9″ | 7″ – 9″ | Versatile sizing for larger vents |
Water-Tite 81695 Multi-Cap Type B Vent Cap
Best for standard 5″ to 7″ B-vent pipes. This cap features a non-clogging positive draft design that helps maintain airflow, reducing the chance of backdraft issues. Clamp fittings are adjustable for common sizes, and the heavy-duty aluminum construction resists rust and corrosion. Choose this if you want a durable cap with straightforward sizing and dependable draft performance.
Best used for residential gas appliances in moderate climates. Limitation: not optimized for extreme high-wind environments where specialized wind caps may offer better protection.
SELKIRK CORP 106800 6-Inch Round Top
Best for gravity-draft venting on LP or natural gas appliances. The 6″ round top design helps promote draft continuity and reduce moisture buildup at the vent exit. It’s not intended for wall furnaces or wood-burning applications, making it ideal for straight-through residential vent runs. Select this option if your system relies on gravity-assisted draft rather than forced draft.
Limitation: not suitable for wood-burning or wall-mounted setups, which may require different cap configurations.
DuraVent 4BVVTH 4 in. Type B-Vent Gas Rain Cap
Best for vertical installations above the roof line where rain and debris are concerns. This cap offers improved performance in windy or rainy conditions and helps prevent rainwater intrusion into the vent. It’s designed for 4″ Type B-vent piping. Choose this if you have a roof-penetrating vent and want added rain protection.
Limitation: sized specifically for 4″ vents; may not fit larger pipes without a different cap model.
Simpson Dura-Vent 8” DuraVent Type B High-Wind Cap
Best for large-diameter vent runs, the 8″ high-wind cap provides robust protection against wind-driven downdrafts. The aluminum Type B vent cap is designed to endure challenging weather while maintaining ventilation for gas vents. It’s a strong pick for homeowners with larger vent pipes or high-wind exposure.
Limitation: selection is specific to 8″ vent piping; not suitable for smaller ducts without changing caps.
Water-Tite 81696 Multi-Cap Type B Vent Cap
Best for larger 7″ to 9″ vent pipes, this cap provides the same non-clogging draft design and adjustable clamp fittings as the 81695, but scaled for bigger ducts. It helps resist rust and corrosion with heavy-duty aluminum construction. Choose this if your system uses a wider B-vent run and you need reliable performance across a broader size range.
Limitation: larger footprint may require compatible chimney or vent throat dimensions; verify compatibility before purchasing.
Buying Guide
- What size is your vent? Start by measuring the outside diameter of your B-vent pipe to choose a cap that fits 5″–7″ or 7″–9″ ranges.
- What climate do you live in? For windy or rainy regions, prioritize high-wind or rain-cap designs to minimize downdrafts and water intrusion.
- Material matters. Aluminum caps resist rust and corrosion well; stainless steel offers stronger corrosion resistance in harsh environments but may come at a higher cost.
- Draft needs. If your appliance relies on positive pressure, a non-clogging draft design helps maintain efficiency and reduces debris buildup.
- Installation simplicity. Caps with adjustable clamps simplify sizing across standard vent ranges without additional adapters.
- Compatibility. Ensure the cap is designed for Type B vent piping and does not specify wood-burning or wall-furnace use unless intended for those applications.
FAQ
- What is a Type B vent cap?
A Type B vent cap is designed for B-vent piping used on gas appliances, providing weather protection while allowing safe exhaust gas venting. - Do I need a rain cap for my B-vent?
Yes, rain caps prevent water entry, reduce debris buildup, and improve vent longevity, especially in wet climates. - Can I use a 7″ cap on a 6″ pipe?
Cap sizing must match the pipe diameter; use an adjustable clamp or a model that covers the required range if available. - Are stainless steel caps worth it?
Stainless steel offers excellent corrosion resistance and longevity in harsh conditions, but aluminum caps are typically sufficient for standard residential use. - How do I know if a wind cap is better for my roof?
Wind caps are specifically designed to resist downdrafts; use them if you live in high-wind areas or have roof obstructions that affect venting. - What should I avoid when choosing a cap?
Avoid caps not rated for Type B vent piping or caps intended for wood-burning installations unless your system requires them.