If you are having a problem either keeping your fire lit or having smoking problems, installing an outside airsource 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, so 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 airsource. An outside air source is a vent that provides fresh air to feed the fire.
For years building codes in most parts of the country have required these to be installed during new construction and 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 Their is a verity of styles found 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 don’t open as they have been rusted shut or the homeowner is not familiar with how and when to open or close them. We have all sealed our homes up as tight as an envelope with air tight windows, doors, weather stripping, and attic insulation and our appliances are air starved. That is why building codes require outside air to be supplied to all gas fire appliance including 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.
An outside air source can make getting a fire started in your chimney easy even 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 being painted 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.
Having an outside air source installed is generally not a costly process, but consulting a professional over where to systematically place the vent is recommended. 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.