Rheem Performance Platinum 11 GPM 199000 Btu Natural Gas Tankless Water Heater $700 + fs (possibly less after rebate)

prp007

Yesterday 2:48 PM

707 Comments

Joined Dec 2018

prp007Yesterday 2:48 PM

707 Comments

Any insights about the product? I have 2x50 gallon tanked gas heaters. Can I replace both with this tankless one or I will need 2?

1

xllbenllx

Yesterday 3:26 PM

1.4K Comments

Joined Jul 2009

xllbenllxYesterday 3:26 PM

1.4K Comments

Quote from prp007

:

Any insights about the product? I have 2x50 gallon tanked gas heaters. Can I replace both with this tankless one or I will need 2?

Really depends how much water you use at one time, but generally you exchange 1:1. Sounds like you've got a big house, and 1 tankless will likely be insufficient. I would get 2.

1

antaholics

Yesterday 6:17 PM

295 Comments

Joined Aug 2013

antaholicsYesterday 6:17 PM

295 Comments

Quote from prp007

:

Any insights about the product? I have 2x50 gallon tanked gas heaters. Can I replace both with this tankless one or I will need 2?

That's more of a throughput question... this heater can heat 11gal/min. If you use less than that at any given time, theoretically this can go forever. A typical shower is 2.1gal/min between hot and cold. If you start running multiple showers, the dishwasher, multiple washers, etc... all at once, then you might need a second one. If it's intermittent or long running (e.g. consecutive showers for 40 minutes each) then this is probably enough.

Tank water heaters heat much more slowly, but the 50x2 gallons is already hot, so you get hot water until the tanks get too cold.

Last edited by antaholics September 2, 2026 at 11:19 AM.

4

Shawndak07

Yesterday 6:47 PM

868 Comments

Joined Jul 2018

Shawndak07Yesterday 6:47 PM

868 Comments

Quote from prp007

:

Any insights about the product? I have 2x50 gallon tanked gas heaters. Can I replace both with this tankless one or I will need 2?

Very likely. You could also have one tank as a tempering tank to further assist.

2

manolobindo

Yesterday 11:38 PM

1.5K Comments

Joined Sep 2017

manolobindoYesterday 11:38 PM

1.5K Comments

Note that *actual* gpm (vs what's in marketing material -- 11gpm in this case) depends much on the temperature rise: how many degrees it must raise the incoming water to reach its setpoint. Basically the gap between the incoming water temp (eg are you in cold/hot climate? Is it summer/winter?) and what temp you have your heater set at. Since this greatly determines how "hard" your heater has to work and therefore what its real-world throughput might be.

For example, in Seattle right now I'm getting 65f out of tap and my tankless (Navien, 200k btu) is set at 120f, so that's a rise of 55 degrees. All else equal *actual* GPM would be different if either/both of these variables were different.

Other factors, too, of course. Main point is to understand the advertised GPM rating so that you're not surprised 😉

Last edited by manolobindo September 2, 2026 at 04:41 PM.

1

stateboy

Today 12:26 AM

187 Comments

Joined Mar 2018

stateboyToday 12:26 AM

187 Comments

Quote from manolobindo

:

Note that *actual* gpm (vs what's in marketing material -- 11gpm in this case) depends much on the temperature rise: how many degrees it must raise the incoming water to reach its setpoint. Basically the gap between the incoming water temp (eg are you in cold/hot climate? Is it summer/winter?) and what temp you have your heater set at. Since this greatly determines how "hard" your heater has to work and therefore what its real-world throughput might be. For example, in Seattle right now I'm getting 65f out of tap and my tankless (Navien, 200k btu) is set at 120f, so that's a rise of 55 degrees. All else equal *actual* GPM would be different if either/both of these variables were different. Other factors, too, of course. Main point is to understand the advertised GPM rating so that you're not surprised 😉

I agree with this wholeheartedly. I had one in a different part of Michigan. If you look at the box it comes in where the instructions, it'll show decreasing groundwater temperatures the further you get north in the country. I've got some pretty icy feeling water coming out of my tap in the winter in northern Michigan. That's going to take a lot more energy and a larger temperature spread to get to 120 degrees out of the tap if that was a desired temperature setting. This unit will slow the water flow down if it comes in too cold to make sure that it comes out to the temperature you're requesting. I wouldn't get 11 gallons per minute where I live. It would be closer to 6 or 7 gallons per minute.

1

AlpeshP

Today 1:34 AM

301 Comments

Joined Nov 2012

AlpeshPToday 1:34 AM

301 Comments

Just my 2 cents but get one with a recirculation pump or add one if possible. I have a navian with the pump and having instant hot water is amazing especially when cold out. Even though I live in Texas it's still an amazing feature.

1

PabIo

Today 2:16 AM

309 Comments

Joined Oct 2019

PabIoToday 2:16 AM

309 Comments

Quote from AlpeshP

:

Just my 2 cents but get one with a recirculation pump or add one if possible. I have a navian with the pump and having instant hot water is amazing especially when cold out. Even though I live in Texas it's still an amazing feature.

Second this

stateboy

Today 11:24 AM

187 Comments

Joined Mar 2018

stateboyToday 11:24 AM

187 Comments

Quote from AlpeshP

:

Just my 2 cents but get one with a recirculation pump or add one if possible. I have a navian with the pump and having instant hot water is amazing especially when cold out. Even though I live in Texas it's still an amazing feature.

I like the idea of the recirculation pump but from what I could find on this unit (reading the Q&A on the Home Depot site), it could also be bypassed and not used, which is more inviting for me at this point. I would have to add additional plumbing to an existing home to put a recirculating line in. Perhaps, someday I'll own a house or build a house where I could enjoy this feature of instant hot water instead of delayed hot water.

abstractj

Today 4:42 PM

3.2K Comments

Joined May 2006

abstractjToday 4:42 PM

3.2K Comments

The review on this one is sus.

fundlimited

Today 4:52 PM

93 Comments

Joined Mar 2012

fundlimitedToday 4:52 PM

93 Comments

Over 50% off with very bad reviews. Sounds like Rheem is getting rid of this bad design.

Rheem Performance Platinum 11 GPM 199000 Btu Natural Gas Tankless Water Heater $700 + fs (possibly less after rebate)

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