How To Select The Right Chimney Cap
What if your fireplace only smokes during high winds due to bad chimney flue caps? What is happening is powerful back drafts from the overhead winds are blowing down your chimney. You should install the proper size chimney flue caps on the top of your chimney in order to deflect some of the wind.
But how do you select the best style and type of chimney flue cap? If you need to find the right chimney cap for your home, then you should read this article and discover more about dampers, flue pipes and caps.
How Chimneys Work
While you don’t have to know not how to build your own chimney…you should understand some of the basic technology involved. Just understand that a chimney is really nothing more than a tubular device that is designed to pull exhaust fumes up and away from the fireplace and expel them into the outside air.
Once you have a fire going, the chimney damper (the manual air flow valve) along with the chimney creates a draft or suction. So the hotter the exhaust fumes that are released the more powerful the draft being created. The draft has a vacuum effect which prevents smoke from escaping back into the room and pulls the fumes outside.
The narrow channel in the chimney, is called the flue, and must be insulated using a flue liner. This allows the exhaust gases to remain hot until they can be pulled or expelled outdoors. This is why a flue liner increases the draft. Once the fire is going, a working chimney and damper create a giant feedback loop.
As we mentioned before, the chimney cap or flue pipe cap, stops high winds from blowing down into the house, pushing smoke and debris into your living space. While it's not very hard to find chimney flue caps, there are four things you should always keep in mind during the selection process: shape, type, metal and size.
1 Shape
First, what shape should your chimney flue cap be? For safety sake, walk around your home until you can see your chimney and with a pair of binoculars or using the zoom function on your camera look until you see the flue (the pipe sticking above the brick or stone that has the smoke coming out of it). Flues are either round, square or rectangular in shape. If you have more than one flue, the shape is probably rectangular.
2 Types
If the flue is poking above the concrete pad on around the pipe, then you can use a single flue cap, otherwise you probably will need either a top mount chimney cap or else one custom made to fit.
3 Metal
While copper chimney caps are great looking, not everyone has the budget for such fanciful materials. Depending on your budget, you may have to look at stainless or galvanized steel for the best valves.
4 Size
What size should you get? Unfortunately, either you or a contractor has to climb up on the roof and make careful measurements of your flues, chimney and chimney crown (the concrete pad that surround the pipe).
Now that you know a bit about chimney flue caps, you can start researching the types and sizes you may need to solve your back draft problem.
