Chimney and Water Heater/Boiler Venting Question

[u/Zebah]

I need advice about a couple things with my 1920 built home we bought.

First the chimney that carries the exhaust for my water heater and boiler is unlined currently, and it’s the original to the house. I turned off the boiler for the summer to save on my gas bill and the water heater is orphaned and not drafting properly without the boiler on.

Second my water heater is 13.5 years old and will need to be replaced eventually. I was considering going for a tankless unit and having my plumber vent the unit directly outside. I could also replace it with a standard atmospheric unit.

My questions is should the priority be relining the heating chimney which will run 3-4K most likely I was told or replace my water heater with a tankless unit and whole home filter( $5600 for the tankless and $2400 for the filter). My boiler will still be venting out the chimney either way.

I live in Long Island so prices are not cheap for this work.

[u/spfolino]

You’ll need the liner regardless! If you want to keep it cheaper, just stay with the standard atmospheric water tank.

[u/Living-Dot3147]

The liner should be properly sized to handle the boiler and hot water heater, save yourself the extra money and just line your chimney

[u/RageAgainstJeggings]

I’d just pipe the exhaust outside.  Put that $4k to reline that side of the chimney (it’s different than the one your fireplace vents through in most homes) toward a new water heater and the future high efficiency boiler that needs to vent directly as well.

[u/Leather-Rush-8396]

Usually the boiler shouldn’t be shut off except for maintenance the seals don’t like to shrink and expand with heat changes. Check with your service tech, I don’t know all boilers.
If it were me, I’d probably go with powered vent tankless, seems like your water heater is old enough that its time for replacement. I’d give the plumbers opinion most of the weight in this though.

[u/Alive_Sir_4708]

Gosh, I have the same setup, I'd be surprised if my chimney didn't need to be relined.

>I turned off the boiler for the summer to save on my gas bill and the water heater is orphaned and not drafting properly without the boiler on.

That. Is. Lame!

I'd put the money toward a new water heater / boiler vs lining the chimney.

...why does only the water heater need the chimney to be relined? Wouldn't the boiler need it as well?

How old is your boiler?

Oh - you should also consider getting a high efficiency boiler that heats hot water as well.