Yes, I am well aware for the most part they are highly inefficient for frequent use.
My cabin has a 25 gallon tank that is on its way out. It feeds the kitchen sink, bathroom sink, and shower.
The cabin gets used in the spring and summer only.
Mainly washing hands and quick showers.
The cabin is about the be completely rewired so I figure adding a 240 under the sinks and behind the shower would be a wise idea.
What units should I look at?

Seisco
https://www.seisco.com

Your gonna need a lot of power.

Whole house tankless water heaters
RA22 requires (2) 50 amp circuits
RA28 requires (2) 60 amp circuits
RA32 requires (2) 70 amp circuits

Specs can be found here.
https://61c201d1-8456-4e55-835...adf887c5ab2033df.pdf

My son-in-law's brother is a plumber. When my water heater died a couple years ago, I asked him about electric tankless; he said they were all junk and would not recommend them. Gas, yes. Electric, no.

Did you get the electrical service upgraded when you had BIL/Friend/Whoever rewire it? If not likely you don't have a large enough service to do it.

I have a tankless water system in my house, 15 years not a problem, unlimited hot water. They have been in use in Europe, and Asia for decades, I would never go back to a tank again.

Tankless doesn't seem to make a whole lot of sense with electric, but makes a whole lot of sense with Natural gas. Electric draws a ton of amperage and usually the service isn't large enough to support swapping one in.

That being said a house I used to manage, was a vacation rental, It has a Rhinnea natural gas mounted on the exterior of the house in 2012, it has NEVER missed a beat or had a failure. Sometimes the house isn't used for 3 weeks, sometimes it has 6 people staying in it for a week straight. The Rhinnea's seem to be one of the best ones.

For everyday use in a full size home then Electric isn't the thing, but for part time use in a cabin, it would be the right thing to use since gas or propane isn't easily available.

If you can haul up propane for the time you are there then it's more efficient than electric but then if you have to BYOP, maybe it's not ideal.

We have a propane unit here, does great, no shortage of hot water, the only issue is time for hot water to reach the farthest away faucet and that's not that big of a deal, you have some of that with a tank anyway.

Is the cabin roof getting sunlight? Maybe a solar water heater with an electric in-line would be good, that way you'd have a tank of sun warmed water, which raises the starting temp of the tankless, reducing start up time.

Thats the big thing to consider, whats the water temp average coming into the tank, the lower the temp the higher BTU you want and the longer to raise it to temp.

YOu can also put a recirculation tank inline and the tankless will circulate water to keep it warmer or hot.

I seem to remember this whole issue from your past thread.
IMO you are over thinking and over complicating this whole thing.

Just replace the standard old everyday water heater and be done with it for another ten years.

quote:

Originally posted by Skins2881:
Did you get the electrical service upgraded when you had BIL/Friend/Whoever rewire it? If not likely you don't have a large enough service to do it.

Nothing has been done yet.
That cousin dropped off the face of the earth winter hit so I shut everything off and have not worried about it.

Another cousin is supposed to do it now. Need to link up with him but would like to figure out what units so the proper electric is available for me to put the units in.

Again folks I am not looking at while house units.
I am looking at 3 separate point of use units.

quote:

Originally posted by Mustang-PaPa:
I seem to remember this whole issue from your past thread.
IMO you are over thinking and over complicating this whole thing.

Just replace the standard old everyday water heater and be done with it for another ten years.

Having the tank is a gigantic pain. It takes up a bunch of space in the kitchen.
I have to drain it and it takes while to get hot water once we are there.

Will be a whole lot easier to have 3 point of use units so all I have to do is flip the breaker when I get there and we are rolling. Flip the breaker before I leave shut off the water and run the pipes out.

quote:

Originally posted by Black92LX:
Yes, I am well aware for the most part they are highly inefficient for frequent use.
My cabin has a 25 gallon tank that is on its way out. It feeds the kitchen sink, bathroom sink, and shower.
The cabin gets used in the spring and summer only.
Mainly washing hands and quick showers.
The cabin is about the be completely rewired so I figure adding a 240 under the sinks and behind the shower would be a wise idea.
What units should I look at?

Are you talking about installing something like 3 of these?

https://www.grainger.com/produ...86!!!g!469890691366!

Or this?

https://www.amazon.com/Rheem-R.../?tag=lifeheaters-20

^^^ pretty sure the top one can't supply a shower only sinks.

I haven't seen any point of use ones for a shower before, doesn't mean they don't exist but I've never wired one. Under-sink yes, whole house yes.

quote:

Originally posted by smlsig:

quote:

Originally posted by Black92LX:
Yes, I am well aware for the most part they are highly inefficient for frequent use.
My cabin has a 25 gallon tank that is on its way out. It feeds the kitchen sink, bathroom sink, and shower.
The cabin gets used in the spring and summer only.
Mainly washing hands and quick showers.
The cabin is about the be completely rewired so I figure adding a 240 under the sinks and behind the shower would be a wise idea.
What units should I look at?

Are you talking about installing something like 3 of these?

https://www.grainger.com/produ...86!!!g!469890691366!

Or this?

https://www.amazon.com/Rheem-R.../?tag=lifeheaters-20

Correct.

quote:

Originally posted by Black92LX:

quote:

Originally posted by smlsig:

quote:

Originally posted by Black92LX:
Yes, I am well aware for the most part they are highly inefficient for frequent use.
My cabin has a 25 gallon tank that is on its way out. It feeds the kitchen sink, bathroom sink, and shower.
The cabin gets used in the spring and summer only.
Mainly washing hands and quick showers.
The cabin is about the be completely rewired so I figure adding a 240 under the sinks and behind the shower would be a wise idea.
What units should I look at?

Are you talking about installing something like 3 of these?

https://www.grainger.com/produ...86!!!g!469890691366!

Or this?

https://www.amazon.com/Rheem-R.../?tag=lifeheaters-20

Correct.

So each of the Rheem’s would require a 60 amp 240 v. breaker.
How big a service do you have for your cabin?

Were it me I would put in a compact water heater maybe 30 gallon. If the panel box isn't easy to get to have a switch put right there near the heater so you can switch it on when you first arrive. Rig a drain near the heater, it can even just go outside, so come Fall when you drain your lines it's easy to drain the tank. Cheap and simple.

Current Situation!!!


But going to have the cabin completely rewired so trying to figure out how much juice we’ll need.

quote:

Originally posted by ridewv:
Were it me I would put in a compact water heater maybe 30 gallon. If the panel box isn't easy to get to have a switch put right there near the heater so you can switch it on when you first arrive. Rig a drain near the heater, it can even just go outside, so come Fall when you drain your lines it's easy to drain the tank. Cheap and simple.

That is how it is currently done.

Someting to keep in mind. The farther North you live, the colder the groundwater temp. Instant water heaters work better in the South cause the ground water is warmer. The colder the water, the more energy it takes to heat the water to the desired temperature. This will also limit the number of showers you can have on the heater.

Another option, check into a Marine water heater, they're not cheap, but then again 3 at the source instant water heaters aren't either. The marine water heaters are extremely fast at recovering, are small and might be a better option. On a yacht with 4 people taking showers in a row (2 showers, you don't run out of hot water with one of these small water heaters.

I would go with Raritan, seaward or Kuma, they're very impressive and blow away the household water heaters as far as keeping the tank hot and have stainless steel tanks. One around 10 gallons would probably be equivalent to the 30 gallon household you have now and plenty for your entire cabin but they make up to 20 gallon ones......

https://www.westmarine.com/water-heaters

quote:

Originally posted by Black92LX:
Current Situation!!!


But going to have the cabin completely rewired so trying to figure out how much juice we’ll need.

Awesome! That’s what we call in the trade a “rat’s nest”.