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Old 02-15-2017, 05:39 AM   #1
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Default tankless hot water

Thinking about installing a tankless hot water unit on my boat, looking to free up some space, i want to use the space to have all my pumps on one side for easy access, has anyone done this and what unit did you use, its just for occasional shower , we do not live on the boat, i have a 7 or 10 gal now, thank you
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Old 02-15-2017, 06:21 AM   #2
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Tankless water heaters take a huge amount of AC power. How will you power this tankless hot water heater?

For example my tankless hot water heater at home takes three 60 AMP 240 volt AC services.

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Old 02-15-2017, 08:11 AM   #3
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^Agreed. And those little ones that are "point of use" and pull 15-20A at 110VAC are a joke. Check the reviews on amazon.
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Old 02-15-2017, 11:07 AM   #4
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Originally Posted by aquaholic23 View Post
Thinking about installing a tankless hot water unit on my boat, looking to free up some space, i want to use the space to have all my pumps on one side for easy access, has anyone done this and what unit did you use, its just for occasional shower , we do not live on the boat, i have a 7 or 10 gal now, thank you
1st, you'll need a generator... There's no way to run this of an inverter... 2nd, keep in mind that the 110 volt tankless water heaters are pretty lackluster performers... Of course, if you have a 220 volt generator it's a good solution...

In all other situations you're better off with standard hot water tank... And, if you have inboard engine(s), consider hooking up the engine's cooling water to the tank... Free hot water...
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Old 02-15-2017, 05:32 PM   #5
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hot water only works when generator is running or i am on shore power, so you think i should just keep my hot water tank, ive seen a few that run on 110 but i dont know anyone who installed on on their boat,
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Old 02-15-2017, 05:33 PM   #6
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I've tried them residential and commercial, and definitely prefer the traditional tank systems. Most likely won't go the tankless route again.
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Old 02-15-2017, 06:43 PM   #7
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You loose the ability to manage power consumption with a tankless unit. When ever someone turns a hot water faucet on bam! You are pulling another 25 amps or much more. Not good when running multiple acs, and wife turns on microwave and hot water at the same time. With my 12 KW gen set I turn on my 10 gallon water heater for 30-45 min and I'm good all day. When time for evening showers I'll turn on water heater again and make sure other optional high power consumption devices such as microwave.
, hair dryer aren't used. Note I usually have 2 or 3 ac units running and if all three compressors are running they could pull about 35 amps. So when replacing I will stay with conventional tank with a 1500 to 2000 watt element.
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Old 02-15-2017, 06:48 PM   #8
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thank you,
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Old 02-15-2017, 06:55 PM   #9
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I'm in the process of going with tankless electric with new home construction. Only option is propane, for either tankless or storage. Considering there are seldom more than 2 people living in the house, electric tankless looks to be far more efficient, and, since its a 1600 sq. ft. cottage on conditioned crawlspace, the electric is 1/3 the size, and does not require annual service, and electric here is more predictable in cost than propane.

However, that said, for a boat I would go propane, and even explore if there are any diesel heaters available...I had a rural house briefly with an oil-fired tank-type water heater heater, but like most fuel-oil things, needed annual burner service, which adds-up quickly.

OP, a lot will depend on boat size, which you didn't mention...as mentioned by others, electric tankless needs LOTS of juice, more than you can expect from an inverter (I don't think there are any marine tankless heaters that run off DC, but research that also), for example, which means running a jenny for showers...forget having a supply of HW available on demand at sinks, and do obvious conservation measures like short showers, with very low-flow shower head.
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Old 02-15-2017, 11:27 PM   #10
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Quote:
Originally Posted by aquaholic23 View Post
hot water only works when generator is running or i am on shore power, so you think i should just keep my hot water tank, ive seen a few that run on 110 but i dont know anyone who installed on on their boat,
I have a 220 volt tankless electric in my warehouse... It serves the lavatory, the kitchenette and the shower... Longest run is 10'... It works fine... Even when 2 usage points are being used concurrently... I think that if you have the power available it's a viable option onboard...

For land use I think that a single 220 volt unit for the whole house is less likely to work... IMHO a dedicated unit for every bathroom and one for the kitchen is a more effective option...
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Old 02-16-2017, 04:40 AM   #11
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i have a natural gas tankless at my home, it works great, and its on demand so its effecent, but on my boat it would be electric as the only option, i just wasnt sure if one of the small tankless would be enough for a shower, im doing some research ....
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Old 02-16-2017, 08:06 AM   #12
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Originally Posted by aquaholic23 View Post
i have a natural gas tankless at my home, it works great, and its on demand so its effecent, but on my boat it would be electric as the only option, i just wasnt sure if one of the small tankless would be enough for a shower, im doing some research ....
Like I mentioned above, the 110v/15-20A point of use instant HW units suck. I've used them. The temp rise they are capable of at the rates they can flow are about good enough to wash your hands as long as luke warm water is ok. Def not hot by any measure. Amazon reviews are your friend.
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Old 02-17-2017, 03:59 AM   #13
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gotcha, thank you,
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Old 02-17-2017, 08:25 AM   #14
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I rigged this hot water shower up on my boat, takes 10 minutes to set up or less and then stows out of the way when I don't need it. Nice to rinse off after a day of diving on overnight trips. Water can get so hot you can make a cup of noodles if your hungry. Unit was about $140 if I remember correctly, bought it at an RV place. Use my onboard shower for water in, portable propane tank for fuel and water gets instantly hot.

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Old 02-17-2017, 10:11 AM   #15
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Amazon has that, very highly rated.
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Old 02-17-2017, 05:26 PM   #16
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Ask stevethebrain, I'm sure has a well thought out plan. That is if it doesn't blow your boat up first. Lol
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Old 02-18-2017, 01:03 PM   #17
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Now that is a rig! Especially like the integrated deck brush with shower head. ����
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Old 02-18-2017, 02:08 PM   #18
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Ive had a tankless gas hot water heater in my house for about 6 years. We love it. No problems other than once a year service to clean out

Gas bill is tiny. Take as many showers wash as many clothes as you want.

Have an old electric tank heater on the boat. Works ok and don't think it would be worth the cost to change it.
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Old 02-19-2017, 04:03 PM   #19
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Nice rig Greeno.
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