Why burn outside air? - The Fireplace Technician (2024)

FAQs

Why burn outside air? - The Fireplace Technician? ›

If outside combustion air is provided for the fire, the opposite happens: heated air expands, so the house becomes positively pressurized, which tends to carry heated air TOWARD all the cracks, helping to distribute the heat throughout the house.

This kit is so important because the dedicated air source allows the fireplace or stove to pull air from the outside for combustion. When the doors and windows are sealed tightly, air can only pull from the inside of the home, which could create negative pressure inside the room your fireplace is in.

1 Exterior Air. Factory-built or masonry fireplaces should be equipped with an exterior air supply to assure proper fuel combustion unless the room is mechanically ventilated and controlled so that the indoor pressure is neutral or positive. — R1006. 1.1 Factory-built fireplaces.

The main reason most people need to use an external air kit with their wood-burning stove is when the room in which their stove is located has insufficient ventilation. The types of scenarios in which an external air kit is required include: The room in which you are placing the stove does not have a non-closable vent.

While it heats the area directly in front of it, it is sucking the air from inside your home and sending it up the chimney; a process called the chimney-effect. Whatever heat you had in your home will be replaced by cold air being sucked in through any leaks around windows, doors, etc.

The second handle you may find in your fireplace (usually located on the left inside panel) is a control lever for the outside air kit. When burning your fireplace, the outside air kit lever should always be in the open (or up) position. The outside air kit is designed to provide additional air for combustion.

The requirements for combustion and dilution air for gas-fired appliances shall be in accordance with the International Fuel Gas Code. 701.2 Combustion and dilution air required. Every room or space containing fuel-burning appliances shall be provided with combustion and dilution air as required by this code.

Flue Obstruction

The build-up of creosote, soot, and other debris can gradually restrict the airflow inhibiting the venting of smoke and exhaust. Small animals like birds, raccoons, and squirrels can enter an open flue through a damaged or non-existent chimney cap and cause an obstruction.

Dirt and Grime

Gas fireplaces are much cleaner than wood-burning ones, but they can still become dusty and collect grime over time. This can lead to problems getting the fireplace to turn on because the dirt over the burners will prevent them from getting enough oxygen to ignite.

Combustion Air – (1) Air that is supplied to combustion appliances to be used in the combustion of fuels and the process of venting combustion gases. Inadequate combustion air can lead to dangerous problems. (2) The duct work installed to bring fresh, outside air to the furnace and/or hot water heater.

Should the air vent be open or closed on a wood-burning stove? ›

When lighting your stove, open both air vents fully. On initially lighting, it can be an advantage to crack the door open slightly to provide additional air flow through the firebox. Once the fire is established, close the door and then close down the bottom air vent gradually.

I can't see how a wood stove could reduce the oxygen level, as it takes in air from the house then vents it out of the house. The only way it could reduce the oxygen level would be if the house was so tightly sealed that it actually reduced the air pressure in the house.

For example, a 5kW stove would need 2,750mm2 of ventilation. An 8 kW stove would need 4,400mm2 of ventilation.

Several reasons include wood moisture, improper combustion, negative pressure, and kindling/wood placement during startup that can lead to smoke entering the home.

A fire needs oxygen to burn. If you had a sealed room, eventually all that oxygen would be used and the fire would go out. There are normally specifications as to the size of ventilation for a fire. It can be a duct running under the floor, a ventilator set in the wall or vents set into a window etc.

A fireplace creates a column of heated gas inside the chimney. As that air rises, more heated air from the fire is pulled after it. The result is a draft -- a steady flow of smoke and hot gases -- up the chimney. The draft serves another purpose, too.

Direct vent technology: A sealed combustion system protects indoor air quality by drawing outside air for the fire and expelling 100 percent of combustion exhaust and byproducts outside the home.

Across the United States, the majority of residential homes cooking with gas do not need to vent their range. However, just because you don't have to does not mean that you shouldn't. If you use a commercial-style range, then you will be required to do so.

Explanation: Oxygen is essential for combustion. Burning the gas in the presence of oxygen is essential for producing clean flames. If there was no air inlet in the stove, the kerosene/gas will not burn till it gets oxygen.

Ventless gas fireplaces are deemed to operate within the range of safety for cycling these combusted gases back into the home's interior. By contrast, vented gas fireplaces create a dangerously high amount of combustion exhaust and therefore must be vented to the outdoors.