Best water heater to fill a spa tub

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Donald

Donald

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Aside from our 50 gallon tank running out of hot water when the tub is 1/2 full the gas tank heater is fine. And it is not old.

Reading the other thread on tank vs tankless.

I have read about the "booster" but have not sure they will do what I want.

I am looking for a solution that won't cost me extra energy for the 99% of the time when we are not filling the tub.
 
Only tankless system will not cost you extra energy. Expect to pay in excess of $1000 for a tankless system installed. Much more in CA. That will buy a lot of gas.

You can raise the temperature on the water heater so you can blend some cold in with the hot. I bet it is set at 120. Try 140. If you have hard water, more minerals will precipitate out at that temp, so you will have to flush your tank more often. When that water heater fails you can go to tankless and do the flue and gas pipe or a bigger gas. Gas water heaters have become quite expensive lately. Replacing with a bigger gas conventional will have the lower installed cost.

Rod
 
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If you have a large enough gas line at the gas water heater , add another 50 gallon gas hearer . You can even plumb them in series ans the second one essentially becomes a storage tank with a burner to keep the water from cooling off .

From what I read , tank less are a bad idea if you have hard water ( we do ) . Also , They require either a large gas supply / pipe or large electrical supply / wire / circuit breaker . Your existing gas or electric service may need to be up sized . Certainly a large the gas pipe or electric circuit will have to be installed to the unit .

None of this is cheap .
 
Originally Posted by Donald
Aside from our 50 gallon tank running out of hot water when the tub is 1/2 full the gas tank heater is fine. And it is not old.


Another option would be to raise the temperature of your hot water, and then add in one of those valves that mixes in some cold water with your hot to reduce the temperature a little.
 
Others have hit on it, but in a nutshell:

1. Raise the water temp in the water heater you have now. This will allow you to blend in more cold water and still hit the desired temperature. The danger is the tap water will be extremely hot and could burn a user quicker. Not a great choice if you have kids.

2. Add a second water heater.

3. Get a bigger water heater to replace the 50 gallon one you have.

4. Add an inline on-demand heater on the line to the tub. May require electric or gas upgrades.

5. Go whole house tankless.


Option 1 may get you closer to where you want to be.

Everything else will cost a chunk of money...
 
Formula for how many gals of hot water to cold
% Of hot water
( Mixed water temp -cold water temp) divided by ( hot water temp - cold water temp)

If you would pipe two water heaters in parallel then you have twice the hot water and the correct way to pipe them for equal flow is first in last out. Where if the heaters are side by side. Left heater supply piped first teed to right heater. Right heater hot water out first teed to left heater. Then the pressure drop between heater are identical piping doesn't have to perfect lenght or the heaters don't have to match.
 
Originally Posted by WyrTwister
If you have a large enough gas line at the gas water heater , add another 50 gallon gas hearer . You can even plumb them in series ans the second one essentially becomes a storage tank with a burner to keep the water from cooling off .

From what I read , tank less are a bad idea if you have hard water ( we do ) . Also , They require either a large gas supply / pipe or large electrical supply / wire / circuit breaker . Your existing gas or electric service may need to be up sized . Certainly a large the gas pipe or electric circuit will have to be installed to the unit .

None of this is cheap .


Tankless have gotten much better in recent years. Yes if you have hard water you will need to flush every year, but that is not different than a tank, you have to drain the sediment in a tank every year too. There are several tankless out now that can run on 1/2" gas under certain conditions.

The intital cost of tankless is higher, but not drastically. A high quality 50 gallon tank costs 600-800 now. A 7.5GPM tankless costs a little over $1000.
 
I considered a tankless a few years ago when I lived in NJ but with the cold water temp was 45 degrees in winter. Requiring 115 amps and a new 200amp service.
 
tankless works alot better if you dont have hard water, and the incoming water temp is not low..

For example here I'd need 65F heat rise and 6gpm.. and the city water has quite abit of minerals.
 
Originally Posted by ragtoplvr
Only tankless system will not cost you extra energy.


+1 on the tankless. My Rheem can turn turn the water temp up to 140 Degrees F.
 
Tankless is the way to go for occasional very heavy use. Just make sure not to undersize it. Tankless won't work for a recirculating system if you have a large home.
 
Cant you just turn up the water temp a few hours before filling the tub? then turn it back down afterwards? Once the tub is full it must have a heater in it ...I thought they all do otherwise the temp will drop very quickly.
 
Originally Posted by doitmyself
Would a small point of use tankless heater work for this???

One example: https://www.homedepot.com/p/EZ-Tank...-Tankless-Water-Heater-EZ202NG/207158891


The problem is you turn on the water to fill the spa tub and the faucets are all the way open for 3/4" pipe. So a lot of GPM. Its going to take a large tankless heater to keep up. Not a situation where you have reduced flow shower heads.
 
We empty our spa for the winter, fill it in the spring and another drain/fill in late summer. I'll fill the tub, leave the large cover off and only leave the solar cover on during the day until the temp comes up to ambient air temperature or if there's enough sunlight for the solar cover to do it's job and bring the temp higher. Once I see the rate of increase has dropped off, we add chemicals and let the inline heater take of the rest of the work to bring the tub up to 100F.

Sorry, after I submitted this I realized you were referring to an indoor spa tub and not an outdoor one.
 
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I have a 70 gallon HWH for my Jacuzzi tub. Builder spec'ed it out for us when we built the house. Said we needed the larger size if we got the large tub. It's a Bradford & White HWH.
 
Get a Rheem or AO Smith tankless gas water heater. Get one no smaller than 180,000 BTU. These are excellent trouble free heaters. Forget the rest. They are problem prone.
 
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