Just wondering if any body out there has been installing any of the instantanous electric water heaters. I see that some of these require 120 amps. I realize that these would have to be subdivided. Wondering what the payback period is because of the initial cost and having to increase the size of the service. I know to calculate the payback period you would need to know how often it is used. But just wondering what some of you guys thoughts are. I would imagine that utility company would have to set a much larger transformer if supplying a large commercial building with several of these or if feeding several houses that had these installed.
Instantanous water heater
- Thread starter CONDUIT
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marti smith
Senior Member
In our neck of the woods there are not too many due to the hardness of the groundwater, even with the use of a softener. Although on the plumber's side, the system should be installed with a backflushing device that allows a cleaning fluid to be added to remove the sediment build-up, and extend the life of the heater. Otherwise, one may never obtain the calculated return as it is lost to maintenance cost. This is just one of may variables to factor in.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
The only instantaneous water heaters I have hooked up that are 120V are the instant hots for a particular sink or the whole house units that are gas fired but need 120V for the controls and fan.
If this was a totally electric unit for the house it would need about 100 amps to work properly. They are not worth it, IMO but the gas units seem to have a greater appeal. My friend installed his own from Lowes and he loves it-- never run out of hot water.
They make alot of sense rather than heating a whole tank & not using it most of the day.
If this was a totally electric unit for the house it would need about 100 amps to work properly. They are not worth it, IMO but the gas units seem to have a greater appeal. My friend installed his own from Lowes and he loves it-- never run out of hot water.
They make alot of sense rather than heating a whole tank & not using it most of the day.
ceb58
Senior Member
- Location
- Raeford, NC
The only totally elect. unit I installed needed 3-40amp 240v circts. ran to it. It was new construction and I knew what was going in from the beginning so the larger service was planed for. Customer called me back about six months latter to disconnect the unit, change the feed to 120v for a gas unit. He stated the elect. one would cook you in the shower for the first few min. then freeze you the rest of the time.
mikeames
Senior Member
- Location
- Germantown MD
- Occupation
- Teacher - Master Electrician - 2017 NEC
Really, Why is this??? I would assume if the flow rate and water temp are consistent then he output would be as well? Regardless I would rather the gas.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
They cause more problems than they are worth. Lights will flicker because you keep turning on and off a huge load. Very costly to install and hard on POCO in many older areas like Tampa. I installed 1 and within few days asked to unhook 1 of the 3 because of the flickering. I don't want one in my house if you gave it to me and installed for free. Gas ,yes and never heard a complaint yet.
readydave8
re member
- Location
- Clarkesville, Georgia
- Occupation
- electrician
I periodically see new style electric water heaters that are better than the old style ( the ones that the customers were unsatisfied with).
And then a few years later they are the old style that didn't work very well.
It doesn't seem like there's a way to do magic with heating elements, the kilowatts used still correspond to the btu's produced.
And then a few years later they are the old style that didn't work very well.
It doesn't seem like there's a way to do magic with heating elements, the kilowatts used still correspond to the btu's produced.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
If you add insulation around a typical 40 gal water heater you will not lose that much energy to get concerned over. Your going to need several years to even think you saved anything after the install price and if you read up on them hard water destroys them fast. If gas is available go for it but not tankless electric
Gas WHtr for sure is the best.Around here I've been having to run power to a small holding tanks,,10 gallon or so.This tank is connected to a small recirculating pump.Almost as good as a instaneous unit.The constant flow of water helps prevent the gas from cycling on until the flow rate is called upon.Most of the time this is applied to a tanless gas water htr supply.
If I was using electric I'd use a 2 tank 50gallon ea.paralel storage system .Def. not the tankless
If I was using electric I'd use a 2 tank 50gallon ea.paralel storage system .Def. not the tankless
kwired
Electron manager
- Location
- NE Nebraska
The only real loss is during cooling season, during heating season all the heat loss just takes away from the needs of the heating equipment.
ptonsparky
Tom
- Occupation
- EC - retired
Had a customer asking about these a couple years ago. I went into why the were not a good idea on his service. 125amp, long distance with min sized conductor, etc. His question was not if he should but if he had protected the circuits with the proper sized CB. He had no complaints at that time. Whole house electric tankless. Time will tell.
mivey
Senior Member
The only value is an unlimited amount of hot water.{add: or in a location that is hardly ever used} They are not as efficient as the high-efficiency tank electric units.
Undersized or cheesy units
Because gas units are not undersized and you can deliver a lot of BTUs with gas without flickering your lights.
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The input water temperature is never consistent. Instantaneous water heaters usually have smaller reservoirs (smaller gallon capacity). The tank is usually at house temperature. In the winter as you drain it you pull in water at outside temperatures. So people set the instant temperature really high and get burned by the original tank water, then freeze when the icy water hits the tank and cannot be brought to temp. Not so instant.
mivey
Senior Member
I would not want one for my house either. Now, for a rarely used out-building sink: yes
If I HAD to have one for the house, I would use gas. Even so, they are not as efficient as you can get with electric, so I would not put one in.
mivey
Senior Member
On the contrary, you can get a heat pump hot water heater that steals energy from mother nature. Then the efficiency (comparing BTUs out to kWh in) is greater than 100%.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
I do know of a campground/resort that uses one for heating pool and hot tub. Anyone have link for them ?
ceb58
Senior Member
- Location
- Raeford, NC
That is the conclusion I came to.
Should not have been undersized. It was a Rudd unit. $$$$$
marti smith
Senior Member
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
- Status