Does anyone know anything about chimney liners?

[dennis thompson]

My plumber was doing some work next to my gas hot water heater, he noticed that the flue from the hot water heater was cold (it should have been hot) & told me he thought my chimney might be blocked. I called a chimney repair service & they said there was no blockage & that the problem was that the hot water flue was a 4" pipe going into an 8" flue causing it to not draw properly & that I needed a chimney liner. I called the local building inspector & he agreed with the need for a liner. I got two estimates one for $850 & one for $1100. The $1100 estimate included an insulated liner while the $850 did not include insulation. The flue is on an outside wall. I called the $850 estimator back & asked him about the insulation & he said, given that only the gas hot water heater was going into the flue, insulation was not required. I imagine he is right,if insulation were required he certainly would have included it, particularly after I asked him about it. So what do you think, should I go with an insulated liner (an extra $250) or the uninsulated liner? They are both stainless steel & include new chimney caps. Note that both of these chimney repairmen were recommended by my local building inspector.
Thanks
Dennis

[Mike Davis NC]

Since it will be inside the flue i would think that is insulation enough. It shouldn't be cold enough to cause condensation in the pipe.

[Myk Rian]

We have both furnace and water heater going to the same flue liner. Un-insulated, and no problems. The brick chimney is enough for it.
Had all kinds of problems with the bricks cracking from freezing moisture until the liner was put in.

[ray hampton]

I would call the building inspector and ask him/her about the liner,will the liner be touching the inside wall of the flue ? if the liner are position away from the flue inner wall [ next to the house ] then this will be a type of insulation

[David Helm]

The most important thing is having the flue liner the correct size for the appliance. 4 inch is typically correct. As you have noted, the larger size cools the gases too fast and causes condensation in the pipe. I would go with the unlined.

[Mike Archambeau]

Spending that kind of money to line a chimney for a gas hot water heater makes me wonder if you would be better off putting the money into a more efficient hot water heater. A super high efficiency hot water heater can be vented into PVC pipe which would allow you to avoid the current masonry chimney altogether. Or you could put the money into a tankless water heater, again allowing direct venting to pvc or if you use electricity to power the tankless, no venting is needed.

Today there are more efficient ways to heat hot water than the old fashioned gas hot water heater, so spending that $1000 on more efficient equipment instead of a flue liner could save you money in the long run.

[Peter J Lee]

I didn't even know you could get insulated. I think I'd pass on that. Do you like the placement of your current water heater. It's often dictated by the need for a chimney which you would no longer need if you replaced it with a power vent model. Its a plus for air quality as well. At some point, you could also take down your chimney, at least below the roof line and eliminate a pretty significant heat loss. I know at one time there was even a state refund for people who did that in Wisconsin.

[Pat Barry]

For a natural gas water heater I don't believe you need stainless liner. I believe aluminum is acceptable. Its worth checking because the cost difference is huge.

[Michael Weber]

Spending that kind of money to line a chimney for a gas hot water heater makes me wonder if you would be better off putting the money into a more efficient hot water heater. A super high efficiency hot water heater can be vented into PVC pipe which would allow you to avoid the current masonry chimney altogether. Or you could put the money into a tankless water heater, again allowing direct venting to pvc or if you use electricity to power the tankless, no venting is needed.

Today there are more efficient ways to heat hot water than the old fashioned gas hot water heater, so spending that $1000 on more efficient equipment instead of a flue liner could save you money in the long run.

Agreed, that's a lot of money. I put in a high effeciency furnace and the pvc was a snap to run out a wall. A new tankless that uses pvc vent will probably run you quite a bit more if you pay to have it installed but might be worth it depending on the age of your current water heater. There's one in my future when time allows for installation.

[Ed Hazel]

Yes I would get a high efficient Nat gas water heater so you could run PVC I have seen them run the PVC up the old unused flue if you did not want to run to an outside wall.

[Ed Hazel]

We have both furnace and water heater going to the same flue liner. Un-insulated, and no problems. The brick chimney is enough for it.
Had all kinds of problems with the bricks cracking from freezing moisture until the liner was put in.

My dad has had problems with his bricks cracking, were the breaking on the outside of the chimney? I am certain he just has the clay liner in his?