Supplemental Water Heater?

[35k0]

When we built in 2018, we installed a RHEEM 50gallon Lifetime electric water heater. We didn't think about the capacity of my wife's soaking tub....... which holds about 50 gallons of water. She takes a bath nightly. Generally not an issue, unless the kids need a bath before bed, then she is out of hot water when she wants to take a bath.
So, I am wondering what you all think would be the best route. Are there affordable on demand units that will meet the needs of a 50 gallon tub? Should I upgrade the 50 gallon water heater to a larger unit?
What would you do?

 

[The Cobbler]

On demand units if sized properly will deliver continuous hot water , but they will need a huge supply circuit . They are fairly expensive too .
I might consider just adding another tank upstream of the existing one to provide additional hot water .

 

[Mikes61]

There are 75 gallon water heaters, or just install a second 50 gallon one.

A tankless might work, but will burn a lot of gas or electricity.

 

[Kaizen]

Not sure if it meets the "affordable" checkbox but i'd be looking at hybrid water heater with larger size like this one.

https://www.homedepot.com/p/Rheem-ProTerra-65-Gal-Smart-High-Efficiency-Hybrid-Heat-Pump-Water-Heater-w-Leak-Detection-Auto-Shutoff-10-Year-Warranty-XE65T10HS45U1/330317225?g_store=&source=shoppingads&locale=en-US&pla&utm_source=google&utm_medium=vantage&utm_campaign=103680&utm_content=106645&mtc=SHOPPING-RM-RMP-GGL-D26P-026_051_WATER_HEATER_INSTALL-NA-RHEEM-NA-PMAX-NA-NA-MK891599001-103680-NBR-2529-NA-VNT-FY25_Q1_Q4_Rheem_D26P_AON_BAU_Opportunity&cm_mmc=SHOPPING-RM-RMP-GGL-D26P-026_051_WATER_HEATER_INSTALL-NA-RHEEM-NA-PMAX-NA-NA-MK891599001-103680-NBR-2529-NA-VNT-FY25_Q1_Q4_Rheem_D26P_AON_BAU_Opportunity-23071002607--&gclsrc=aw.ds&gad_source=1&gad_campaignid=23066921462&gbraid=0AAAAAolLu994URbXilekFsBwxtiFM6XZG&gclid=Cj0KCQiArOvIBhDLARIsAPwJXOZr-OmqXpBdqxwcI1JnI2NmwWnQGHsSy9rLpSOopR-uBeuxsakin3YaAm2EEALw_wcB

If the kids are girls i'd go bigger. My two took 30 min showers daily.
I put one of these in a few months ago and since i have a Sense panel monitor I can see the savings daily. It costs much more then a basic electric but the payoff is 3 years for me. They have several modes so if the boss uses all the water every night it can run the heat pump all night and make it up. If you find its not enough it has an electric backup that you can select to run. All over wifi.
This is the huge part.....I saved 50 percent on mine with state and electric company instant savings.

 

[gizardlizard]

Get a 75 gallon Bradford White. Wouldn’t even consider buying a water heater from a box box store. Consumer grade junk. Buy once/cry once.

 

[HoosierBuddy]

Curious if NG is available?

Fuel burning water heaters typically recover at twice the rate of electric.

I've been using a 40 gallon NG water heater in our house for over 30 years, and with a family of 5 (2 tubs and a shower) I can't remember ever running out of hot water. I mean, maybe if we had company and you have 7 or 8 people taking back-to-back showers?

Of course if NG is available, lots of people go tankless and then you don't even worry about recovery.

Also NG is roughly 1/3 the cost (when used in a water heater) vs a resistance electric heater. If you have to go electric, then a heat pump style water heater like Kaizen linked to will save you that 2/3 back and be roughly the same cost as NG. YMMV.

Downside with gas is you've got to get a vent out. Mine is a power vent model in the basement that vents out the side of the house.

 

[dave*99]

When we built in 2018, we installed a RHEEM 50gallon Lifetime electric water heater. We didn't think about the capacity of my wife's soaking tub....... which holds about 50 gallons of water. She takes a bath nightly. Generally not an issue, unless the kids need a bath before bed, then she is out of hot water when she wants to take a bath.
So, I am wondering what you all think would be the best route. Are there affordable on demand units that will meet the needs of a 50 gallon tub? Should I upgrade the 50 gallon water heater to a larger unit?
What would you do?

On demand units are discussed in terms of flow capacity and temperature rise. Cold water enters and must be heated to some point well above 100 deg F. I have Navien 180,000 Btu NG tankless units. What does this mean? It can supply about 2 showers simultaneously running on city water in the winter in NJ. And it can do it forever. Is the tub the only consumer during bath time?

But in keeping it simple, if your house is set up for a tank heater and you have space for a larger tank, that sounds pretty easy. Most houses around me with soaking or jetted tubs were built with 75 or 80 gallon tanks.


Temperature Rise

Temp Rise	NPE-210S2
35 °F (19.4 °C) rate	10.1 GPM (38.2 l/m)
40 °F (22.2 °C) rate	8.8 GPM (33.3 l/m)
45 °F (25 °C) rate	7.8 GPM (29.5 l/m)
50 °F (27.8 °C) rate	7.1 GPM (26.9 l/m)
55 °F (30.6 °C) rate	6.4 GPM (24.2 l/m)
60 °F (33.3 °C) rate	5.9 GPM (22.3 l/m)
65 °F (36.1 °C) rate	5.4 GPM (20.4 l/m)
70 °F (38.9 °C) rate	5 GPM (18.9 l/m)
75 °F (41.7 °C) rate	4.7 GPM (17.8 l/m)
80 °F (44.4 °C) rate	4.4 GPM (16.7 l/m)
85 °F (47.2 °C) rate	4.2 GPM (15.9 l/m)
90 °F (50 °C) rate	3.9 GPM (14.8 l/m)
100 °F (55.6 °C) rate	3.5 GPM (13.2 l/m)
110 °F (61.1 °C) rate	3.2 GPM (12.1 l/m)
120 °F (66.7 °C) rate	2.9 GPM (11 l/m)
130 °F (72.2 °C) rate	2.7 GPM (10.2 l/m)
140 °F (77.8 °C) rate	2.5 GPM (9.5 l/m)

 

[sparky 1971]

At another house I had a 40 gallon electric water heater installed ahead of a 50 gallon gas. There was never a need for the electric heater to get turned on but was there if it was needed and having it full of closer to room temperature water seemed to really help the recovery time of the gas water heater. I also put in valves so that either water heater could be used and the other bypassed in case of a failure.

 

[ipgenie]

Might not work with your tub or wiring, but they do make a heater that plumbs in line with the jet pump and helps keep the tub water warm. This would only work if the tub has jets and there is a circuit available to connect it. It might be enough to heat up the water if the tank runs short on hot water.

 

[rust in the eye]

Might not work with your tub or wiring, but they do make a heater that plumbs in line with the jet pump and helps keep the tub water warm. This would only work if the tub has jets and there is a circuit available to connect it. It might be enough to heat up the water if the tank runs short on hot water.

Perhaps an on demand heater could be plumbed into the existing jetting?
If a plain tub a point of use might keep up if fed from the hot side of your existing set up. Not sure if that's recommended but a thought.
No NG? I'd hate to pay the electric heat bill for a home in Minnesota.