I got a brand new water heater for my upstairs bathroom only . My shower is a six headed shower and my tub is a huge jacuzzi . So I could just use the hot water for my bathroom without worrying the water will go cold i got a brand new electric 30 gallon and I installed it but noticed it Runs out of hot water fast if I use all the shower heads or even just 2 on together. But if I use one it lasts a normal shower period but I have 6 shower heads I’d like to use. Also the tub / jacuzzi only fills up 10 percent and then gets very cold sooo fast more faster then the shower . And it’s only one faucet that fills it with very high pressure. How is this possible if it’s a new water heater and only heats for that bathroom no where else?? And it’s just me who uses the bathroom ?? Is there a setting I missed ?

simply put... the water heater is grossly undersized.
at best you get 70% of the capacity of the tank (70 x 30 = 21 gallons) of nice hot water. after that is starts to provide tepid water not hot.
whoever advised you to get a 30 gallon electric heater did not do you any favors.

THIRTY GALLONS???????????????? That is just enough for a one room apartment with a single tenant. I am surptised you get that mush hot water from it.

Lol no @#$%& !! What size would be good?

Well it’s just me and I have a big one downstairs I just wanted this bathroom to have it’s own I thought it was enough the men told me it was at the store lol.

well ashley, what you have is inadequate so you need to decide what you want to do and how much money you want to spend.
if it were my problem, i would run a hot water pipe from the bigger heater on the first floor using it to feed the heater on the second floor. (rather than feeding the smaller heater with cold)
this seems to be an inexpensive way out for you and should supply you with ample hot water.
as a side note. calculating what size water heater is needed for jacuzzi and shower is a job that should be left to those who know more than we do. you simply go on line to the proper site, give them all the info they require and cross reference a chart that will tell you.

You could also install a mixing valve. Turn the heater to the max then set the mixing valve to 120.

i'll bet you didnt tell the men at the store that you had a shower with 6 heads. You have to take the gallons per minute (GPM) for each head and add them up. If a homeowner told me they wanted a shower with 6 heads, I would suggest a large tankless heater, and one tankless might not be enough GPM. Most tankless heaters put out 5 to 8 GPM. There is a Super high efficiency Rinnai heater that puts out 9.8 GPM, but I'll bet it's expensive.

The mixing valve is a good idea, but I don't think it would provide enough mixed hot water. If it was an electric 50, maybe, but probably not a 30.
Most people with multiple heads and body sprays don't use everything at once. If you keep the 30 the way it is, you'll have to get used to not using them all at once. Sorry. If "the guys at the store" knew what they were doing, they would'nt be working there.

are those six heads body sprays? Do they spray at the same time or you have control on which ones to turn on off together and separate?

If each head is rated 2.5GPM six heads will give you 15GPM! Although I doubt your pipes can support that anyways I think 1/2" can delivers 14GPM theoretically but that depends on your actual valve is it a pressure balanced or thermostatic if it's pressure balanced the inside channels of these valves are much smaller than the 1/2" or 3/4" pipes that feed them so the real bottle neck is in these valves.

Let's say to run your shower you need a flow rate of 10GPM, Your 30 gallon WH gives you 21 gallons of hot water "theoretically" but the tail end of that will be half warm. That 30 gallons of hot water is mixed with some cold water to achieve your desired shower temperature. Assuming you mix in 25% cold water, which is 5.25 gallons, to give you a total of 26.25 mixed volume to consume. If you are consuming at 10GPM, you will start to run out after 2.6 minutes. So one solution is to keep your shower shorter than 2.6 minutes.

or to look into gas tankless units.

or use a conventional single shower head.

I have 30 gallon water heaters at my one bedroom apartments. They are barely enough if two people take back to back showers in the morning. They get 10 minutes each.



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Two ways of looking at it. Either your water heater is grossly under-sized, or your bathtub is grossly over-shower-headed.