Outside Air Sources

Outside Air Source
This air vent may alleviate smoking problems.


Fireplace problems?

If you are having a problem either keeping your fire lit, installing an outside air source may be beneficial. Keeping a fire lit takes different factors including air and fuel for burning. The products of combustion include water vapor and carbon monoxide. Being sure that the fireplace will vent properly is very important to the safety of the home as a whole. One way to improve air flow is to install an outside air source. An outside air source is a vent that provides fresh air to feed the fire.

Building codes in most parts of the country have require these during new construction. Thus, most homes already have them. They look like a small rectangle iron grate, and most often located on the back wall of the firebox. These normally slide to the right and left to open or close. There is a variety of styles around the country, some being round in shape. They to supply air from the outside so as not to rob  air from the living space of the home. My experience is that many will not open. They’re rusted shut or the homeowner doesn’t know how to open them. We have sealed our homes up tight. Think about our air tight windows, doors, weather stripping, and attic insulation. That is why building codes require outside air for all appliances. This includes fireplaces, hot water heaters, and furnace equipment


A fire that burns well will actually increase draft. In order for a chimney to draft properly, there must be a good air flow from the firebox to the top of the chimney. The fire in the firebox warms the flue system so that the products of combustion will flow up and out of the chimney. If the flue system is too cold the outside air coming down the chimney may be heavier than the products of combustion coming up the chimney which can cause a smoking problem. If installing an outside air vent does not solve your problem, a less intrusive repair would be to install a SmokeGuard which makes the size of the firebox smaller so that the products of combustion may be vented more efficiently.


Fireplace Smoking Problems
Installing a SmokeGuard is simple.


Ample Air

An outside air source can make starting a fire in your chimney easy for beginners. With ample outside air and a good set up of kindling and good, seasoned wood, anyone can get a nice fire burning. One thing I will caution you about when it comes to outside air sources is to watch them when they get painting over. Whether the vent is an outside air source or simply a vent on the front of a wood stove feeding the fire in the stove with air from the room, if you get the area painted be sure that the air vents are not painted or sealed shut. This can cause problems, especially if it is a vent on the front of a wood burning stove that requires the air in order for the wood to fully combust.

Consulting a professional

Having an outside air source is generally not a costly process, but consulting a professional over where to systematically place the vent is a good idea. The professional The professional should  discuss with you both indoor and  outdoor variables such as other competing appliances in the home, large hills, trees, or other obstructions that possibly may be a factor for a sluggish draft.

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Clay Lamb

Clay Lamb is a Cincinnati Chimney Sweep contractor and the executive producer of the YouTube channel, podcast, and blog Ask the Chimney Sweep. He is also an award-winning educator and public speaker in the chimney and fireplace industry. AsktheChimneySweep.com….Educational Videos AmChimney.com….American Chimney Cincinnati, OH We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

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