Electric tankless water heater

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oscarcolumbo

Member
Location
Florida
So we just had to do a service upgrade just so that the home owner can install an electric water heater. I’ve done this two other times and I really don’t like doing it. I mean these things require two 60 amp breakers! I’ve seen some that require two 80 amp breakers!! I think the next time someone asks me to do this again I’m going to say no, It’s just too much of a pain. Anyone else feel the same? I can’t see running two sets of # 4 for just a water heater!


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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
What the customer wants and is willing to pay for, the customer gets :)

As a customer I can't imagine wanting a large tankless electric water heater. But I do love my gas tankless to pieces. Modern ones handle both high flow and low flow with no problem at all, and never running out of hot water: priceless.

-Jon
 

StarCat

Industrial Engineering Tech
Location
Moab, UT USA
Occupation
Imdustrial Engineering Technician - HVACR Electrical and Mechanical Systems
About Tankless heaters

About Tankless heaters

So we just had to do a service upgrade just so that the home owner can install an electric water heater. I’ve done this two other times and I really don’t like doing it. I mean these things require two 60 amp breakers! I’ve seen some that require two 80 amp breakers!! I think the next time someone asks me to do this again I’m going to say no, It’s just too much of a pain. Anyone else feel the same? I can’t see running two sets of # 4 for just a water heater!


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Tankless water heaters, no matter gas or electric are one of the Engineering blunders of the century.
Like a lot of other so called modern " Tek " they are not worth having. This category also includes all gadgets that are prefixed with the word " smart."

SC
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
There are at least some places for them. I have a small (40 amp, 240 volt) one in my shop, so it draws no power 99.99 percent of the time.
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
I'm a little surprised power companies permit them to be hooked up without a demand meter. They don't run 99% of the time, demand a yuge slug of power (but not a lot of energy) when they do, and can't be scheduled or interrupted -- totally antithetical to the smooth operation of a power system, especially one with a large fraction of sustainable energy.

How does the cost of new service and a tankless heater compare to a large tank-type heater with a normal-size element? I live in the northern midwest, where natural gas is the norm and it's somewhat alien technology.

It's a tankless job, but somebody's got to do it. :p
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
We installed a seperate 200A commercial service , just for an on demand hot h20 unit that serves a 9 unit joint in town:ashamed:

I actually made an effort to thwart the landlord,:happyno: who was sold on it by the manufacturer & manufacturer's specs, stats, etc...

the poco upp'd the service xformer 15-50K:cool:, the usage tipped quickly over to 'commercial rates' , the landlord has had yours truly,as well as a gaggle of plumbers , follow up to no avail....

moral? :? 110.3B is probably the most biased tool for manufacturers in NEC history

hold my calls, i'm saving the planet.....:lol:

~RJ~
 

growler

Senior Member
Location
Atlanta,GA
What the customer wants and is willing to pay for, the customer gets :)

There is an old saying about some people having more money than brains.

I have never recommended these large electric tank-less water heaters to anyone. But it is hard to turn down money if they insist.
 

mivey

Senior Member
I'm a little surprised power companies permit them to be hooked up without a demand meter. They don't run 99% of the time, demand a yuge slug of power (but not a lot of energy) when they do, and can't be scheduled or interrupted -- totally antithetical to the smooth operation of a power system, especially one with a large fraction of sustainable energy.

How does the cost of new service and a tankless heater compare to a large tank-type heater with a normal-size element? I live in the northern midwest, where natural gas is the norm and it's somewhat alien technology.

It's a tankless job, but somebody's got to do it. :p
They should be moved to a demand rate and will be on some systems. Same goes for DG and other load management equipment behind the meter as it changes the load profile from typical to atypical.
 

mivey

Senior Member
Wouldn't a heat-pump unit with a tank make more sense?
It does to me. About 30% of normal run cost or thereabouts. A well-insulated tank has minimal loss.

IMO, people get too happy about comparing old weak insulated tanks with instant units. Kind of like comparing new LED with old or low-efficiency fluorescent.
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
Wouldn't a heat-pump unit with a tank make more sense?

It would depend on where the heat that was pumped went, and if it had to then be pumped again by air conditioning. Also it is physically much bigger.
For me, I have a natural gas tank type that works fine. Came w/ the house 20 years ago. I don't know what the average life span for the heat pump units is.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
It also amazes me when people constantly run out of hot water they blame it on their water heater. Simple concept is to run your tank type heater at 140-160 deg F then either install a tempering valve or just turn your faucets towards cold so the water is comfortable. That way you use much less hot water from the tank and it will last a lot longer. People think that they need to turn down the temperature to save money but that's wrong. Even at 160 the outside of the heater will be barely warm so standby losses are minimal and the burner or heating elements will actually need to come on less because you aren't emptying the thing every time you take a shower.

Personally I can see no advantage to tankless. They are expensive to install, require maintenance and, especially electric are expensive to operate. I also don't know their life span, replacement is expensive as well. With tank type heaters the rule is 7 years (though many last much longer than that) and they are inexpensive to replace.

-Hal
 
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OldSparks

Member
Location
Vacaville CA USA
Occupation
Retired: Electrician, Submarine Electronics (21 years), Potable water system maintenance boss (21 years).
It also amazes me when people constantly run out of hot water they blame it on their water heater. Simple concept is to run your tank type heater at 140-160 deg F then either install a tempering valve or just turn your faucets towards cold so the water is comfortable. That way you use much less hot water from the tank and it will last a lot longer. People think that they need to turn down the temperature to save money but that's wrong. Even at 160 the outside of the heater will be barely warm so standby losses are minimal and the burner or heating elements will actually need to come on less because you aren't emptying the thing every time you take a shower.

Personally I can see no advantage to tankless. They are expensive to install, require maintenance and, especially electric are expensive to operate. I also don't know their life span, replacement is expensive as well. With tank type heaters the rule is 7 years (though many last much longer than that) and they are inexpensive to replace.

-Hal

+1
 

kwired

Electron manager
Location
NE Nebraska
It would depend on where the heat that was pumped went, and if it had to then be pumped again by air conditioning. Also it is physically much bigger.
For me, I have a natural gas tank type that works fine. Came w/ the house 20 years ago. I don't know what the average life span for the heat pump units is.
As mentioned the heat is supposed to be pumped into the water.

OK! "It depends on where the heat comes from".
In particular you do not want to draw heat from environmental spaces that you have to pay to heat in the first place.

That is something to consider. During cooling season, you are lessening the cooling load on the general environmental space, during heating season you are adding load to it. If you have longer cooling season than heating season it may be more worthwhile than the other way around. If you have all electric heating/cooling system - might not matter all that much but can depend if you have seasonal changes in energy rates, or other special rate structures that may or may not be advantageous.
 
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