What Is the Difference Between Roof Cowls?
China Mans Hat vs Vertical Jet vs Fibreglass Roof Cowls
It is one of our most common questions. What Roof Cowl do I need? Or what’s the difference in them? Roof cowls play a critical role in ventilation systems. They protect the duct from adverse UK weather conditions of course, but they also ensure efficient airflow for both supply and exhaust systems, and offer different airflow patterns.
Let’s get an understanding of how to pick the correct roof cowl for your ventilation set up!
China Man Hats
These are by far the most common and cost effective cowl on offer. Built from galvanised steel, the simple cone top design allows supply or exhaust airflow from the sides. China Man Hats from Fresh Air Supplies also have a bird mesh to stop birds or large debris entering the duct.
We recommend using a China Mans Hat cowl for basic systems. They are perfect for standard commercial or light industrial use.
Limitations – China Man Hat cowls would not be ideal for systems where directional control of discharge air is important. For instance, exhausting air from a busy kitchen where grease and smells are likely to be exhausted; it would be preferred that these be pushed up into the atmosphere at the first instance to avoid lingering smells or even grease build up on the outlet due to resistance.
Vertical Jet Cowls
A much more superior item. The vertical jet cowl is designed to discharge air upward at high velocity. They are used when extracted air has to be projected away from the roof to prevent re-entry to the supply systems, contamination (grease / particle build up) or unwanted smells. The vertical jet cowl is also often also called a Swedish Roof Cowl.
They also have the protective bird mesh at the top opening to stop birds and debris. Rainwater that enters the cowl is collected in an internal bowl and drained out the side, protecting the ductwork.
Fibreglass Roof Cowls
Another great cowl is our fibreglass roof cowls. Made from UV-stabilised glass-reinforced polyester (GRP), it is extremely durable in external conditions. Again, fitted with bird mesh to stop animal/debris entry. This is a great option as a discharge hood, but more commonly it is paired with a plate-mounted fan for a full air supply / extract capability. The low profile design of the fibreglass roof cowls makes them a popular choice in commercial and residential areas. Often a match for planning regulations, they are considered the most “pretty” and discreet cowl to choose from.
To conclude
So, what’s the answer to your question? Which cowl should you go for? This is completely circumstantial to your job intentions and environment. It should be an easy decision though, now knowing what the cowls are best suited to.
China Mans Hat – The most commonly used cowl and the cheapest too! Ideal for standard commercial or light industrial use.
Vertical Jet Cowl – Need to push unwanted odour and particles away from the roof? The jet cowl is your guy!
Fibreglass Roof Cowl – Tough and pretty! The fibreglass roof cowl can be paired with a mounted plate fan for a full supply/extract system.
View our Roof Cowls online Here : https://freshairsupplies.co.uk/product-category/duct-fittings-bends/roof-terminals/
Have you considered what fan to add to your ventilation system? See the full range here : https://freshairsupplies.co.uk/product-category/fans-controllers/
Need some more assistance or have a specific question regarding one of our roof cowls? Get in touch with the Fresh Air Supplies team today!
📞 Call us: 028 867 52336
📧 Email: sales@freshairsupplies.co.uk