Broan-NuTone 634M Steel Roof Cap for 6" Round Duct, for Range Hoods, LoSone Fans, and Bath Ventilation Fans, Black

In HVAC and ventilation systems, the termination point—the roof cap—is arguably the most critical component, subject to constant environmental stress while being essential for system integrity. The Broan-NuTone 634M Steel Roof Cap for 6" Round Duct represents the definitive standard in residential ventilation hardware, providing unparalleled durability and functional reliability. The choice of steel construction, finished in a robust black coating, is a clear commitment to long-term durability. Unlike flimsy plastic or thin-gauge aluminum alternatives, this cap resists physical deformation from high winds, debris impact, and temperature cycling, ensuring the structural seal remains intact for decades. This material quality is vital for maintaining the home's thermal and moisture envelope. Functionally, the design is optimized for low static pressure and superior backdraft prevention. The integrated damper mechanism is precisely weighted and smoothly operating, closing tightly when the fan is off to prevent unwanted airflow reversals (a major cause of energy loss and indoor air quality compromise). When the range hood or fan activates, the damper opens with minimal resistance, ensuring that the appliance operates at its maximum designed CFM (Cubic Feet per Minute). The precise 6-inch diameter ensures a tight, professional-grade fit with standard ductwork. For installations demanding high performance and guaranteed weather resistance, investing in a unit of this caliber eliminates future maintenance and performance degradation issues. It is the intelligent choice for quality-driven ventilation projects.

Very good quality.. both the sturdy roof vent and flexible ducting. The product as illustrated came as ordered. Pleased?... Yes! ... Except, at no fault of the seller, the shipping/delivery company apparently tried to destroy the boxes in handling. The box corners were crushed, one side torn open apprx 10 inches, and the product (metal roof vent) was bent on top and on two sides. Thankfully it was metal. However on a happy note after some elbow grease and metal bending, including repair of the internal baffle, it is 100% usable.

It installed easily enough, being a DIY person. I was disappointed in the waviness of the paint finish and that it was chipped in some areas. Being pressed for time, I just got a spray can of Rustoleum and touched it up. Works well enough and the inspector was happy, but, it does not pass as much air as I thought, the kitchen range hood can "hard pressurize" the flexible pipe/thermal break in the exhaust line, which tells me the vent is restricting flow quite a lot. Time will tell if I replace it with something else. Likely not as long as the range hood seems effective in exhausting the kitchen area.

Replaced an older one fit and worked as advertised.

This is a solid product and a must if you are installing for a decent cfm exhaust hood in your kitchen. Many will just use a 4” vent cap, but that isn’t enough airflow. The louvre in this cap prevents cold air blowing back down the ducting. I deducted some points because the collar for attaching the ducting isn’t really deep enough for many roofs. After you take decking thickness into account you are likely to struggle to get the duct connected and sealed after install. I installed a collar on it before we installed the cap, and it was much easier.

We now have three of these: stove top vent and two for my lasers in my shop. Heavy duty & work great.

Worked for vent hood install.

UPDATE 5/25/2025: Broan-NuTone did send another unit, which had exactly the same seal problem as the first. The quality control is just not there. The assembler could not possibly have missed this since it is a cassette which slides into the housing and the seal and door are on the top, fully visible. See pictures. This was not the quality I expected. Came assembled incorrectly and the seal installed out of place. Both of these were obviously the result of poor workmanship and also could easily be seen prior to assembly. HOWEVER, Broan-NuTone did replace it without quesiton and were very easy to get a hold of and deal with. This is the reason for the higher stars. I was told by the representative that this product will soon be again manufactured in the USA.

Well built, and exactly what I needed. Was very easy to install.

Arrived undamaged and as advertised

Arrived on schedule. Very durable. Not like the cheat plastic alternative. Thank You

It was easy to install and looks well built but I noticed after few months that they have some rust spots on top not sure if that’s the case with most of them once he paint chips but time will tell how well they stand to harsh Canadian weather

Yes