OThe 20 yo tank water heater I have is about to die. Looking at tankless. Watched a bunch of YouTube videos and google some. What's y'alls thoughts? Worth it? Thx

Where are you located?

Here in bryan.

Yes

Rheem RTGH-90XLN-1 Natural Gas Condensing Tankless Water Heater (Outdoor)

Ordered that model for $1050 last year from TanklessKing. High efficiency unit, greater than 0.93 I think. I recall standard units were 0.8 something.

I think they have one size larger

I bought a house with a propane fired Rinnai tankless water heater and I was skeptical at first but it has performed flawlessly for a year. It is mounted outside on a north facing wall with minimal weather protection.

What size is your tank now ?
Are you running out of hot water from heavy usage ?

Thanks for the reply's guys. I don't know how big it is now. Maybe 50?? Works fine. But it's 20 years plus old. And it's leaking. Plus I could use the space where it is and do a wall mount. I do have to turn on the water for a couple of mins for the shower to get hot.

A new water heater won't deliver water any quicker to your fixtures. You need better insulated lines or a recirc pump for that.

Yes tankless does not equal instant, but it does equal virtually endless. 4 folks in the house. We love ours.

You will need to modify your vent and likely increase your gas line.

As stated above, tankless doesnt equal instant or endless. If you want instant you need a circulation pump or you can combine it with a low boy tank basically used as insulated storage.

It does have a maximum output and if you ask it for too much it will not provide it.

Also, be sure to hire someone to do yearly maintenance om the system. It's very important

Dr. Venkman said:

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You will need to modify your vent and likely increase your gas line.

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Both of these.

You need pvc (white) for a tankless, whereas your water heater might only have abs (black). So that might need to be replaced.

I have a 1.25" gas supply to my house, and my plumber (who I have worked with for 4 years at work) said I'd need a 1.5". That's about $30/ft for replace/install, which is $1000 for me. (Distance from gas meter to water heater, or location of new tankless.)

He suggested a Rinnai RU199 for me, but I'm in CO and have colder ground water.. so just check the cut sheet of any model and make sure you have enough flow rate for your Delta T (hot water temp minus ground water). It would give me about 5 gpm in winter and 7 in summer.

Thx guys. I have a reputable plumber coming. Looks like 1500 to 2500 over the phone. Not sure until he is here what needs to be done. I think this is the route to take. Thx again for yalls time.

Carny89 said:

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Thx guys. I have a reputable plumber coming. Looks like 1500 to 2500 over the phone. Not sure until he is here what needs to be done. I think this is the route to take. Thx again for yalls time.

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I'm assuming that doesn't include an upsized service line, if necessary?

I would anticipate on that cost. Your gas line was likely not designed for a large additional load like a tankless, so very likely you will need it.

I'm not sure. I didn't hold his feet to the numbers. I understand he needs to see it. Just a round a bout in my head. I wonder what size o.d should the gas line be?

Carny89 said:

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I'm not sure. I didn't hold his feet to the numbers. I understand he needs to see it. Just a round a bout in my head. I wonder what size o.d should the gas line be?

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Depends on how many gas appliances you already have.. whatever size that line currently is, it was likely calculated to be that size based on what gas appliances were included when the home was built (water heater, fireplace, dryer, stove, etc). Your typical builder is not going to oversize the gas line for a possibly future tankless add on.

Adding something like a tankless to the list, which requires a lot of gas (4-5x that of a tank water heater), will probably require a larger size gas line.

You might get lucky and have a big enough line.. who knows, but I would just assume you'll need to upsize it.
How old is the house?

http://snowcrest.net/thriftysupply/pdf/RTG-Gas_Piping_Facts.pdf

House was built in 57. So I think everything was on gas at one time.

My water heater is in my utility room and supplies the whole house. If I moved it to the attic and went tankless and basically moved the output supply line from the new heater to the "middle" of the house it would heat up the services faster, correct? It currently take ls about 1 minute of running for my master shower to heat up...

SpreadsheetAg said:

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My water heater is in my utility room and supplies the whole house. If I moved it to the attic and went tankless and basically moved the output supply line from the new heater to the "middle" of the house it would heat up the services faster, correct? It currently take ls about 1 minute of running for my master shower to heat up...

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Technically, yes. That's a lot plumbing to rework by moving it that much, which costs a lot of money. What is the goal of moving it?

Do you turn on master shower all the way hot, and that takes a full minute? My second story master is really far from our water heater in basement, and it takes maybe 20 seconds... all the way on hot.

If you put the valve on mixed hot/cold, you're just wasting cold water, and time, while waiting for hot water to get to it. Put it on all the way hot, then adjust position for temp one it's hot.

It's all the way hot; takes about 1 minute b/c it's on the opposite side of the house about 50 ft away

I was in a similar situation a few years ago, and ultimately decided going back in with a (larger) 50 gallon traditional tank heater.

Primary reasons:
- Inadequate size of gas line to closet where the tankless heater would have gone. There was a 3/4" line nearby, but it was already at the end of a long throw and all the tables I found indicated that it would have been marginal at best (and probably completely inadequate if the nearby 60,000 BTU/hr furnace also kicked on
- Lack of a floor drain for condensate. There's no way around this for a condensing unit, and my house (1974 construction on a slab) would not have yielded easily to this modification.
- Cost. The price of a tankless (including all the gas and water line changes) would have easiliy been 3-4x what the cost of a new tanked heater was. Going back in with a 50 gallon gas unit (only serving two bathrooms) has not led to any issues... yet. Have three daughters who will eventually be teenagers and may need to re-evaluate then.

akaggie05 said:

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I was in a similar situation a few years ago, and ultimately decided going back in with a (larger) 50 gallon traditional tank heater.

Primary reasons:
- Inadequate size of gas line to closet where the tankless heater would have gone. There was a 3/4" line nearby, but it was already at the end of a long throw and all the tables I found indicated that it would have been marginal at best (and probably completely inadequate if the nearby 60,000 BTU/hr furnace also kicked on
- Lack of a floor drain for condensate. There's no way around this for a condensing unit, and my house (1974 construction on a slab) would not have yielded easily to this modification.
- Cost. The price of a tankless (including all the gas and water line changes) would have easiliy been 3-4x what the cost of a new tanked heater was. Going back in with a 50 gallon gas unit (only serving two bathrooms) has not led to any issues... yet. Have three daughters who will eventually be teenagers and may need to re-evaluate then.

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Something you can add down the road to your tank heater to double output for not that much cost


https://www.homedepot.com/p/Heatguard-Water-Heater-Tank-Booster-24409/203721329

Carny89 said:

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I'm not sure. I didn't hold his feet to the numbers. I understand he needs to see it. Just a round a bout in my head. I wonder what size o.d should the gas line be?

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Instead of replacing the gas line, you could increase the pressure at the meter and decrease it back down at the house.

The one thing to keep in mind with tankless is they require a minimum flow to activate. Typically not a huge problem for showers/etc, but if you like to turn the faucet way down to almost a drip when doing things like shaving, you will lose hot water.

Not a huge issue, but something I never thought about.

I think mine is down to 0.4 GPM activation 0.25 GPM sustained to keep active. Needs more than a drip, but shaving/brushing teeth isn't an issue.

Just read manufacturer spec: that's personally why I went with Rheem.

Not trying to de-rail the thread, but does anyone have experience with a recirculating pump, as mentioned above? We moved into a house that has one, and it is awesome to have. However, our cold water is never really cold unless its actually cold outside. The "cold" water is more like cool, than anything else. I assume this is because of the pump. Can anything be done about it?