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suspiciously cheap tankless water heaters

arse_sidewards

arse_sidewards

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May 19, 2020
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My 40gal water heater from 2018 is starting to seep somewhere. Time for a new water heater. I wanted to go tankless last time but didn't have the time and just did a direct replacement.

Old school 40gal tank heaters are $600+ at home depot. The cheap Chinese tankless ones are $200-300. Anyone have experience with them? Seems like they're all direct vent non-condensing so I could convert it to natural/chimney vent pretty easily by screwing with the pipe if the one I get happens to have a concentric intake rather than pulling air from the room.


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If u dont line the chimney to the top it will dry out the teracota flue and it will crumble. Eventually it will fail...block the flue and cause Co to vent into the house.
 
Dejeeper said:
If u dont line the chimney to the top it will dry out the teracota flue and it will crumble. Eventually it will fail...block the flue and cause Co to vent into the house.
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It will definitely condensate and and create issues with the chimney. I used to go out on leak repairs for roofing and it was caused by ng or propane furnaces condensating in existing unlined chimney s
 
Doesn't your ***le kinda give you the answer?
1/3rd the cost...
1/3rd the longevity?
Carry on.
 
Dejeeper said:
If u dont line the chimney to the top it will dry out the teracota flue and it will crumble. Eventually it will fail...block the flue and cause Co to vent into the house.
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What
He
Said

At minimum
Chase it with b vent....
 
Grnjp92 said:
It will definitely condensate and and create issues with the chimney. I used to go out on leak repairs for roofing and it was caused by ng or propane furnaces condensating in existing unlined chimney s
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Why would it do that any more than any other non condensing gas appliance? Are you confusing it with the high efficiency ones?
 
Clb said:
Doesn't your ***le kinda give you the answer?
1/3rd the cost...
1/3rd the longevity?
Carry on.
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Sometimes it’s 1/3 the price 2x the longevity and 1/10th the performance and that’s a situation I’d like to avoid. If it lasts 4yr at $300 and performs acceptably in that time I’d call it a win.
 
arse_sidewards said:
Why would it do that any more than any other non condensing gas appliance? Are you confusing it with the high efficiency ones?
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if it doesn't dump enough heat into the flue pipe it'll condense water
swhy there's minimum btu ratings on flue pipe diameters, not enough heat to keep the walls up above the dew point
run a stick of 3" up through the existing 6" and you'll be fine
 
Much better answer^^^
Arese
If it does as you said, in para 2 it's a win.
If it's para 1 not so much...direct vent into a chase that has ever seen kitchen venting wouldn't be a good idea.
But like 486 said...
 
[486] said:
if it doesn't dump enough heat into the flue pipe it'll condense water
swhy there's minimum btu ratings on flue pipe diameters, not enough heat to keep the walls up above the dew point
run a stick of 3" up through the existing 6" and you'll be fine
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These are all rated at more than double the BTU of my existing water heater.

Edit: I actually need to replace the top of the chimney anyway which is gonna be it's down thread at some point.

Clb said:
...direct vent into a chase that has ever seen kitchen venting wouldn't be a good idea.
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The only stuff going through this flu is natural gas appliances.
 
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My BIL had a tankless WH installed last year. Plumber charged him $150 to de-scale this year. He is going to repeat the de-scale every year. A regular WH will last a long time is you flush it and replace the anode rod every two or three years. My WH's are going on 25 years and no problems.
 
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Funny thing, I'm looking for an anode and so far neither osh nor home cheapo cary one on the shelf...
 
arse_sidewards said:
These are all rated at more than double the BTU of my existing water heater.

Edit: I actually need to replace the top of the chimney anyway which is gonna be it's down thread at some point.


The only stuff going through this flu is natural gas appliances.
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remember these are chinese ratings....
 
Dad has a electric tankless WH. it lasts about 2 years before it burns out the elements due to hard water. I am not a fan at all. the water flow is about half what the cold side is, even when it was new and the water isn't very hot.

When i inherit his place it will be getting a regular tank WH even if it's electric. He is rural so no NG option there.
 
Wades_76_cj7 said:
Dad has a electric tankless WH. it lasts about 2 years before it burns out the elements due to hard water. I am not a fan at all. the water flow is about half what the cold side is, even when it was new and the water isn't very hot.

When i inherit his place it will be getting a regular tank WH even if it's electric. He is rural so no NG option there.
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You'd need a dedicated 200a service to be happy with an electric tankless. They're a joke.
 
I have one of the cheap 16L ones at the cabin for the shower. You have to slow the flow way down to get hot water. I couldn't imagine running a house on one.

To get 108, burner on high, water flow on mid. Just enough it keeps the rv style water pump running.
 
Java230 said:
I have one of the cheap 16L ones at the cabin for the shower. You have to slow the flow way down to get hot water. I couldn't imagine running a house on one.

To get 108, burner on high, water flow on mid. Just enough it keeps the rv style water pump running.
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I have a portable 18L one that claims is does 4.6gpm that I use for filling the hot tub at my rental. To get a out 100 degrees out of it I have to choke it down to the point it takes a about 3 hours to fill the 300 gallon tub.....which comes out to about 1.5gpm.
 
This is the information you actually want.

Would probably work OK for a small household in the deep south, get north of the mason Dixon line and you're not gunna like it.

I've measured water temp under 40f here before in a bad winter



Screenshot_20260605-174758.png
 
Ummduh said:
This is the information you actually want.

Would probably work OK for a small household in the deep south, get north of the mason Dixon line and you're not gunna like it.

I've measured water temp under 40f here before in a bad winter
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Yeah I looked pretty hard at those tables and figured I'd roll the dice come winter. I only need it hot hot for my shower and there's only ever one person showering at once because there's only one shower. Doesn't need to be that hot to feel warm when the house is 60deg :laughing:
 
arse_sidewards said:
Yeah I looked pretty hard at those tables and figured I'd roll the dice come winter. I only need it hot hot for my shower and there's only ever one person showering at once because there's only one shower. Doesn't need to be that hot to feel warm when the house is 60deg :laughing:
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and you can always add one of the 'showerheads of death' if you need a few more degrees of temp rise
 
[486] said:
and you can always add one of the 'showerheads of death' if you need a few more degrees of temp rise
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There's 60A for the range right there. I'd be a fool to not just add an electric tankless inline. I can probably count on one hand the number of times the oven and shower have been in use simultaneously. Mount the ****er horizontal between the floor joists or some ****. :laughing:
 
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