Insulated vs uninsulated flue liner for new water heater?

ratio

Any reason to pick one over the other? I'm looking at this or this, for a new 50 gal 40k WH. Unless the insulated one is available in longer lengths I'd have to order two pieces & join them in the old flue—uncool, but still better than uninsulated?

Also, any reason to not take the flue liner straight down to the draft diverter, or should I stop it at the chimney & run b vent (or single wall?) to the WH?

Ummm...barometric? I have all the instruments to Do It Right, including but not limited to an analyzer with a current calibration. I'll be adding CO (not CO₂!) detectors, interlocked if possible.

This is going in my house, so at least I don't have to worry about keeping the HO happy, just SWMBO.

Larry Weingarten

Hello, both of those look like 4" and I'd expect the water heater to have a 3" vent. Might 3" B-vent work, if you assemble it on the roof and pass it down the chimney?

Yours, Larry

ratio

I ended up going with the uninsulated, as it was about 1/3 the price of the insulated and I could get it in one piece, no splice in the flue. The hold now is a 5" wet core bit. I found a new one on ePay for—get this—$35! I only need to drill one hole with it, I'm hoping it'll make it.

ChrisJ

With all of the money spent on the liner, barometric and interlocks, couldn't you have just gone with a power or direct vent heater?

I was amazed after Sandy when my 50 gallon power vent still had extremely hot water after sitting off for 3 days. I mean, I run it set to 140, but the water was still really hot. I took two short showers with it over those days.

ratio

No barometric, just too much I don't know about them. I admit the job could be done cheaper, but this should give me 15+ years of hot water at greater flow & recovery than I had before, more options when the WH does fail, & most importantly is not where it can't be anymore.

Gordy

Bad thing about power venters no electricity, no hot water after the initial tank full is used.

ChrisJ

Gordy said:

Bad thing about power venters no electricity, no hot water after the initial tank full is used.

Yeah,

But think about all the energy you save over a few million people running power vents or direct vents vs atmospheric? That's not peanuts, it all adds up in the big picture.

People crack me up when they say they will only save $25 a year, or, how they won't have hot water during a rare power outage.

ratio

Not a good match for an instant & no easy spot for a sidewall vent where the WH is going pretty much dictated a conventional model. I guess I could have gone for one with a power damper, but we've had several week-long outages in the last decade so I'm a little shy of adding more dependance on power.

In any case, I should be finishing up this part the coming weekend. @ChrisJ, I stored everything in the basement. I guess I'm too chicken to leave it upstairs for very long.

ChrisJ

ratio said:

Not a good match for an instant & no easy spot for a sidewall vent where the WH is going pretty much dictated a conventional model. I guess I could have gone for one with a power damper, but we've had several week-long outages in the last decade so I'm a little shy of adding more dependance on power.

In any case, I should be finishing up this part the coming weekend. @ChrisJ, I stored everything in the basement. I guess I'm too chicken to leave it upstairs for very long.

No, not really.
My basement is small, and full of tools and to make it worse, those narrow winder stairs are killer.

I really had no alternative.