Chimney cowls provide a lot of benefits and when installed, prevent leaks and also deter animals from getting in. Also called caps or pots, they make for a practical addition to your home, which is why their use is becoming more widespread. If you’re not familiar with these, just read on.
What are Caps and Chimney Cowls?
Chimney cowls are metal ventilators set over your chimney or flue to prevent downdrafts and boost updrafts. These caps also keep wind from sending smoke down your chimney and back into your house. Aside from functioning as a rain guard, these pots also do an excellent job in keeping animals from setting up nests in your chimney.
These flue cowls are known as such because they bear a resemblance to the bonnet or hood donned by monks. The traditional pot is clay red, but today you can find pots made from galvanized steel and in various colors, shapes and styles.
How Do They Work?
Chimney caps are not difficult to figure out. When fire is burning in your fireplace, smoke usually moves up along with the warm air rising by way of a flue to your roof’s chimney pot. If it is windy however, the flow could go down and end up in the flue again.
This ensuing backdraft can send toxic gases and smoke in your house or even start a fire. By installing a pot or cowl, these flue drafts will stabilize and prevent downdrafts. At the same time it increases flue draw, making the most of the burning fuel. So not only do pots prevent downdrafts, but it promotes a healthy environment too.
What Types are Available?
The most popular type of chimney cowl is the H-style or H-pot, and it has a definite advantage over other caps because it stabilizes the draft so your fireplace works more efficiently. These are constructed from H-shaped pipes and work by separating the combustion gases from the turbulence and winds that bring down the drafts. The H cap was first used in marine applications, but its energy efficiency has made it popular, increasing demand for it.
There are other types of pots and cowls available. In fact cowls, caps and pots can refer to any vent or terminal that can be placed in your chimney. The solid fuel insert is a popular variant, and bonnet and mushroom shaped cowls available too. These have a square or round spigot that function like flue vents, but they’re only for unused chimneys.
Others are wind driven and designed to pull fumes and smoke up so they’re ideal if there’s a strong wind. A lot of these cowls revolve while others turn based on the direction of the wind, ensuring they are in the appropriate position to prevent downdrafts. Spark arresting cowls on the other hand, are used on roofs.
A rotating, spinney chimney cowl uses the wind to rotate like a turbine, producing more draft in the process. This generates a vacuum that draws up fresh air at the flue and discards it outside your home. Spinning caps can be useful if dealing with different types of fuels, but it’s usually used for ventilation only. Spinning caps are usually the most expensive type but once installed don’t require a lot of maintenance.
These caps can also be useful to boost draft if there’s extensive downdraught. If you’re going to install one on a wood burning device, ensure the cap is capable of handling the wood. Again, these caps and pots are not just for those with draft issues but want to keep birds, squirrels and other animals away.
Which One Should I Use?
It depends on the type of chimney you have. Stainless steel is ideal for most because it is resistant to creosote, rain and corrosion. If you just need to cap one flue, get one that slides on, but if you have a steel flue or round tile, choose an inside mount cap with brackets so you can push it down. If you have several flues, a cap that connects to your chimney’s exterior might be necessary. Before you by a cap, make sure that it’s capable of handling the fuel you’re going to use (fuel oil, wood, natural gas) and ensure the base fits.
Can I Install a Chimney Cap?
Yes, you can install a cowl. Provided you can get to your chimney from the rooftop you can put the cap in place. If you’re going to install the inside mount variant on a tile flue, use a silicone sealant to caulk it. If it’s a metal flue, don’t use a sealant because metal gets hot and could cause damage.
If the cap will be attached to the chimney, use one anchor for each side and have the anchors spaced by a foot. Slide the chimney cap flange onto the crown and use a level to straighten it. Follow the rest of the product directions given for installing the cap.
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Pros
- A cap keeps water from getting in the chimney. Without it, moisture will get in the flue when it rains and if left untreated cause water to leak in your attic as it flows down, causing damage to the ceiling and walls.
- A cap prevents downdrafts from getting in your home. Downdrafts can fill a room or your entire home with smoke, but a cap can prevent this. More importantly in windy areas, caps make your home more energy efficient.
- If mesh netting is installed, birds and other animals won’t be able to get in your chimney.
- The wire meshes on these caps also function as spark deflectors which are very useful if you live in a dry area.
Cons
- Creosote build up can occur and require cleaning
- Soot might stick on the flue’s sides
Check Out Our Caps and Cowls
We have several chimney cowls for sale including Smart, Draught, Smart Capping, and also H and OH cowls. Each one has a specific purpose and feature set, so feel free to go over them and decide which suits your requirements best.
