I'm working on an 1850s home ...some folks say the two chimneys should have them, and others say not to bother. I plan to install gas heaters things that look like fireplaces.....
If your using a gas appliance in a mason chimney then by code it must be lined. This is for a few reasons.
The newer gas appliances used both in fireplaces as well as heating the home are more energy efficient. Meaning less heat goes up the chimney. The result is flue gasses in many cases will not make it out the top before they cool off.
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As the gas cools down the results are acids and moisture. Both which eats away at the masonry lining within the chimney itself.
Add to that to keep the byproducts of combustion moving up the chimney as they should the size of the interior of the liner comes into play. So with less heat because of better combustion the smaller the flue pipe must be installed in order for it to work properly. A wood burning flue is much larger then that of a gas log system fireplace so the result would be poor venting.
Also a older fireplace system as you have in your home, the masonry systems are more likely to deteriorate with the elevated moisture levels that the gas produces when it burns as well as the acids. then it would if just wood was used.
My advice is to get a professional chimney sweep in and evaluate the current liner that you have and have them recommend the proper size liner that the gas system will require based on BTU input and height of chimney.
Then you need to decide aluminum or stainless steel. The latter is more expensive and works great. As does the aluminum liner, but it must be checked every few years as it can get eaten up by the acids over time.
The newer gas appliances used both in fireplaces as well as heating the home are more energy efficient. Meaning less heat goes up the chimney. The result is flue gasses in many cases will not make it out the top before they cool off. ...»
As the gas cools down the results are acids and moisture. Both which eats away at the masonry lining within the chimney itself.
Add to that to keep the byproducts of combustion moving up the chimney as they should the size of the interior of the liner comes into play. So with less heat because of better combustion the smaller the flue pipe must be installed in order for it to work properly. A wood burning flue is much larger then that of a gas log system fireplace so the result would be poor venting.
Also a older fireplace system as you have in your home, the masonry systems are more likely to deteriorate with the elevated moisture levels that the gas produces when it burns as well as the acids. then it would if just wood was used.
My advice is to get a professional chimney sweep in and evaluate the current liner that you have and have them recommend the proper size liner that the gas system will require based on BTU input and height of chimney.
Then you need to decide aluminum or stainless steel. The latter is more expensive and works great. As does the aluminum liner, but it must be checked every few years as it can get eaten up by the acids over time.
Safety
Life of flue
Efficiency of the appliance