tankless water heater question

I'm still working on a small 20x24 cabin and thinking ahead to a remake of the plumbing system.
I'm thinking electric tankless water heater (Bosch RP27PT). Not concerned with electricity hookup since I will have a 200 amp panel soon. One advantage is saving floor space.
The cabin has a kitchen sink, bathroom sink, shower, clothes washer and laundry tub.
Water source is 95' deep well. Water seems to be in the 40-45F range.
Anyone with experience using a tankless? Pros/cons? Bottomline: Will this unit work or will I be disappointed especially in the dead of winter?
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Franz Fripplfrappl
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Read the specs, it gives a temp rise at a certain gpm. Where is the cabin, you need to know the temp of the incomming water and figure 3-10f lost from pipe to shower head. Will it be one user. Only you can test and run the numbers to see if it works, it could if you do your homework. I have a tankless 117000 Ng bosch, it gives a hot shower with 35f incomming not even being set on high.
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On Thu, 19 Jun 2008 04:49:03 -0700, ransley wrote:

40 miles west of Oshkosh, WI
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Franz Fripplfrappl
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at best one fixture at a time max, shower ONLY with full flow restriction.
with such cold water it will be a stretch at best, and what other electric uses do you have?
might well max out your main service.
electric tankless are well known to be a big disappointment for most users.
how do you heat the building? and water currently?
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On Thu, 19 Jun 2008 05:25:11 -0700, snipped-for-privacy@aol.com wrote:

The present water heater is a 40 gallon electric on its last leg.
The building will eventually be heated by an open loop geothermal system that will extract heat from the well water and then transfer it to radiant floor tubing. Once well water flows through the exchanger it will be discharged to a pond.
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Franz Fripplfrappl
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wrote:

I'm curious as I know little about these systems, but how do you get heat from 40 degree water?
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You use a water-water heat pump. The typical heat pump is air-to-air but suffers when the outside air temperature gets too low. With a constant source at 40 degrees, that problem goes away.
Wayne
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Here we go again, more dissinformation bull s from Mr tank
1 He will not need full shower restriction with 40f incomming , he will get 2.6 gal at 70f rise 2 A "stretch at best" , he has the temp rise and 80 amps extra, my unit has nearly the same btu and not even on high a full flow shower is acheived at 35f incomming 3 He has 200a, the Bosch is 120a, that gives him 80a, doughtfull to max out his service 4 Improper instal or unrealistic expectations-lack of knoweledge of product are what make people unhappy
After slamming the bosch wrongly on many points, one point is true, its not a multi use heater of more than 2.5 gpm, it does only a 70f rise at 2.6 gpm with correct voltage. So if its for a family and multi use get a tank. Also I dought about the savings advantage even bosch is stating a small amount. Electric tank unlike inefficent gas tanks are about 99% efficent, with the price of the bosch on electric you need to see if there is a payback. With gas tankless there is because of gas tank low EF ratings
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Survey says: disappointment likely
Most people seem to be less than thrilled with tankless water heaters, because their capacity is less than what they've come to expect from a traditional water heater. The electric variety especially delivers less volume and less heat.
My brother-in-law just built a new house with a gas-fired tankless water heater. It was only two months before he had the builder replace it with a giganto version, and he lives alone. He also had to have a larger gas supply line run.
I installed trim in a multi-million dollar house. They seemed to do OK with electric tankless, but they put in two of the biggest heaters I've ever seen for every point of use. That's two for each bathroom and kitchen.
If you use a low-flow shower head and don't take really hot showers, you'll probably like it fine, although with 40F water, you're probably pushing the limits.
Check the manufacturer's specifications carefully before you commit. The main things I'd worry about are degrees temperature change at ayour expected flow volume. Be generous with the flow volume. You always use more than you think.
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Steve Bell
New Life Home Improvement
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I also have a cabin, and I'm sure mine is different than yours. We have water from a spring and that water is fairly cool. But it only runs from April 1 to Oct 1, and then that's iffy.
We checked these out. Our problem is that temperatures inside the cabin reach into the teens in the winter. All water systems have to be drained COMPLETELY. When we go there in winter (when the snow is not too high), we carry 100 gallons of water and pump it into barrels in the attic. Then a gravity feed. We use water heated on the stove in a Solar Shower bag for showering, and it works fine.
This year, I want to put a 2 gallon electric hot water heater and an RV pump delivery. This will give us a little better water system than the one we have for winter. Summer water is just like any other place, with a 30 gallon water heater.
That being said, at my cabin, there is going to be a lot of work to install this auxiliary system so that it will totally drain when we leave. Yours may be in the same class, and believe me, the pipe will burst in the most remote inaccessible place you can imagine. So, now, if you can, put the lines where they are either totally insulated or at least easily accessible in case of disaster. As I did, you may want two entirely different separate loops.
Another thing that has been stated: We looked at the tankless systems, and decided NOT to do them for reasons stated. But, the worst negative point was that they are rated to raise the water temperature a specific amount. Starting with 40 degree water, you may only raise it enough to take the chill off of it. Those heating elements are not in contact with the water long enough to get it really hot.
I'd go to a showroom and talk to someone who really knows this stuff. All we have here is good intentions, and sometimes the right answers. But there's no sense of spending a lot of money on a system that won't perform, then finding out that you could have learned that before spending all the money.
Good Luck.
steve
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wrote:

Make the water flow larger.

Put/mount the tank less heater near the kitchen/bath. Take laundry home for washing :)

A new install is most liked, retro-fit, and not following install instructions makes it worse.
Put the heater inside the cabin. vs outside if in snow, In the desert I know of gas tank less (3 on some homes) to be outside.
I've seen about twelve tank less installed. The best method is to ZONE the heater for the demand. A master bath OR even a laundry has it's own zone.
The poor install of tank less I saw was when three units were not zoned. $300.00 later and "options" they worked in tandem.
One heater one zone, Imo. But, you can have a booster pump to another part of the cabin.
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