I just had a new Jacuzzi installed as part of a bathroom remodel and
find that my 50 gallon hot water heater does not have sufficient
capacity to fill it with hot water so I am looking for possible
solutions. The current gas hot water heater is only two-years old and,
except for the jacuzzi, provides plenty of hot water for my wife and
me so I am reluctant to just replace it. The other thing to factor in
is that we had a recirculating pump in the line to the bathroom
because it is a long run from the hot water heater and took a very
long time to get hot water up there. Now it is instant. The reason I
mention this is that I understand that supplemental units usually turn
on when there is water flow in the line and I would not like to have a
supplemental unit running all the time.

Are there supplemental heating units that would work in this
situation? Perhaps ones that turn on only when the temperature in the
line drops below a set limit?

Any help or suggestions for making this work would be greatly
appreciated. I know that I could just replace the current unit with an
80 gallon tank but that seems a waste of money and energy since the
Jacuzzi will not be used a lot.

Thanks in advance - Joel

On Jan 15, 10:35 am, wrote:
I just had a new Jacuzzi installed as part of a bathroom remodel and
find that my 50 gallon hot water heater does not have sufficient
capacity to fill it with hot water so I am looking for possible
solutions. The current gas hot water heater is only two-years old and,
except for the jacuzzi, provides plenty of hot water for my wife and
me so I am reluctant to just replace it. The other thing to factor in
is that we had a recirculating pump in the line to the bathroom
because it is a long run from the hot water heater and took a very
long time to get hot water up there. Now it is instant. The reason I
mention this is that I understand that supplemental units usually turn
on when there is water flow in the line and I would not like to have a
supplemental unit running all the time.

Are there supplemental heating units that would work in this
situation? Perhaps ones that turn on only when the temperature in the
line drops below a set limit?

Any help or suggestions for making this work would be greatly
appreciated. I know that I could just replace the current unit with an
80 gallon tank but that seems a waste of money and energy since the
Jacuzzi will not be used a lot.

Thanks in advance - Joel

Joe-

BTDT, hopefully my experience will be of some use to you.

I have a one person jacuzzi tub (~50 gallon to fill to usable level)
in a master bath as well, 75 gallon propane fired water heater. Most
of the time when the tub is used, the cold water coming into the house
is a bone chilling 40 to 45 deg.

When I first started the using the tub, I'd adjust the temp of the
water coming into the tub to a comfortable level and then let the tub
fill.

Well by the time the tub was about 75% filled to a usable level, the
water coming into the tub was no longer hot enough.......nor was the
"hot" water. The cold water coming into the water heater had brought
the "hot water" temp down to "luke warm".

The modified fill procedure is ....fill with hot water only, to about
75% full.....adjust temp at the end.

Works fine but gotta start with a "fresh" load of hot water, no recent
showers, dishwasher or washing machine usage.

What is the capacity of the tub? If its ~50 gallons, my "hot water"
fill trick should work. If the capacity is much larger maybe not.

Another trick (but requires a little planning) is to boost the water
heater set temp an hour before tub time.

hth

cheers
Bob

well you have some options..........

set the existing tank at max and add a tempering valve, that will
automatically mix hot and cold water to limit the maximum temperature
so no one gets scalded,

you can test this approach set tank as hot as it will go, wait till
the tank is hot burner off, then fill tub

if you can fill tub successfully your all set but add the tempering
valve so no one gets burned.

or add a large high capacity tankless as a preheater , tankless first.

the water must be heated anyway, so preheating costs little beyond the
upfront costs.

the tempering valve is the most affordable approach