Tankless water heater or NO?

[Mike D]

The amperage is not what will dictate the electric bill, the amount used will. High amperage is actually More Efficient in many use scenarios. Even if it takes 60 amps, the power is only flowing while using hot water! I would expect savings once set up correctly and maintained. But also verify if your panels and existing wiring to the main panel locations can even accept the needed power modifications. Homes typically have some leeway but big circuits may even need a new panel and of course will need distribution wiring to handle. Not an electrician but this is common sense. Corrections?

Higher amps doesn’t mean better efficiency but it certainly means higher consumption. And most of these heaters can use anywhere between 90-150 amps. Amps is absolutely correlated to usage.

Amps x volts = watts (or KW if over 1000 watts). You are charged by the kilowatt hour. The kilowatts consumption multiplied by time is what determines how many kilowatt hours used.

Most tank style electric water heaters are fed with a single 30 amp breaker. So you are already requiring 3-5 times more power for the tankless to heat the water.


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[Arrowsmith]

It's regular PVC. One is vent. One is intake make up air. Here is where they daylight on the back side of the house.

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[bboswell]

Higher amps doesn’t mean better efficiency but it certainly means higher consumption. And most of these heaters can use anywhere between 90-150 amps. Amps is absolutely correlated to usage.

Amps x volts = watts (or KW if over 1000 watts). You are charged by the kilowatt hour. The kilowatts consumption multiplied by time is what determines how many kilowatt hours used.

Most tank style electric water heaters are fed with a single 30 amp breaker. So you are already requiring 3-5 times more power for the tankless to heat the water.


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Yes, when heating the tank obviously uses less power. But the tank rats that power 24/7 where the tankless draws 0 KWH unless hot water is being used which is a fraction of the time.

[Greenheadless]

It's regular PVC. One is vent. One is intake make up air. Here is where they daylight on the back side of the house.

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https://youtu.be/ylX2gfggu_o

[Arrowsmith]

We followed the Richmond installation manual.

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[Draco]

Consider yourself lucky. You must have a defective electric meter. [emoji6]Resistive electric heat is the most power consuming, inefficient heat there is.

I’m not gonna say you’re wrong because you pay your bills but I do know about electricity and consumption.

Anything drawing 120 amps is going to make your electricity use skyrocket. There is nothing else in your house that will draw that much power unless both stages of an electric furnace were to come on which just doesn’t happen in Texas.


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You don't know that much about electricity or you would know that those 60 amp breakers would trip if the heater used 60 amps. They are actually using less than 60 amps. The amount of amperage used depends on the temperature of the incoming water. The cooler it is, the more amps required to get the water to the set temp. While my Siebel/Eltron has two, 40 amp breakers, I have never been able to get one to come on even with every hot water faucet in the house on.

[Mike D]

You don't know that much about electricity or you would know that those 60 amp breakers would trip if the heater used 60 amps. They are actually using less than 60 amps. The amount of amperage used depends on the temperature of the incoming water. The cooler it is, the more amps required to get the water to the set temp. While my Siebel/Eltron has two, 40 amp breakers, I have never been able to get one to come on even with every hot water faucet in the house on.

I hope I know a little about electricity. I’ve only been in the trade for 30 years. [emoji57]

Had he provided the KW rating of his water heater I could have provided ACTUAL consumption but regardless 1 x 30a circuit to feed a typical tank style heater is a far cry less that 2 x 60a circuits.

Surely you aren’t that bad at math.


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[Mike D]

Yes, when heating the tank obviously uses less power. But the tank rats that power 24/7 where the tankless draws 0 KWH unless hot water is being used which is a fraction of the time.

Brent c’mon man. You don’t believe that a tank style is heating continuously for 24 hours per day do you?

They do have thermostats on them.


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[bboswell]

Brent c’mon man. You don’t believe that a tank style is heating continuously for 24 hours per day do you?

They do have thermostats on them.


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True, not running but they are maintaining so running on and off.

I agree that you will not save over all with tankless due to increased up front cost but a tankless does use less energy overall.

[Walding1989]

Yes, when heating the tank obviously uses less power. But the tank rats that power 24/7 where the tankless draws 0 KWH unless hot water is being used which is a fraction of the time.

You can install a time clock on that 30 amp water heater circuit and you won’t have that problem

[BigPun]

Gas, yes. Electric, no.
I wish we had gas service here so I could switch to tankless gas water heater. I'm gone all the time and an on-demand heater would save me a bunch of money vs a tank heater that keeps 40-50 gals of water at a given temp at all times.

[meltingfeather]

There’s now way around it. KW is KW and the higher the draw the higher the bill. I suppose if you had a super cheap kWhr rate maybe but my propane water heaters are pretty dang efficient.

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First, cost of fuel/cost to operate is a different issue from efficiency.
And your propane water heater may be cheap to run, but it’s nowhere near as efficient as any electric, tank or not.
Second, you pay for KW-h, not KW, so there’s a factor of how long the thing runs that you’re ignoring. I could draw 120 A for an hour a day and still be using less energy than a 30 A appliance that runs six.

[meltingfeather]

Couple of interesting facts from Consumer Reports:
Payback period for the investment in tankless:
Gas - 22-27 years
Electric - 12-20 years

Falls on its face from an operating cost/ROI perspective. Good luck getting 27 years out of a tankless water heater to recoup your “investment .”

Annual Energy Consumption Cost
Tankless
Gas - $195
Electric - $580

Tank
Gas - $245
Electric- $535

Not including maintenance.

“it’s worth noting that while gas water heaters are less expensive to operate, it’s due to the lower cost of natural gas and not because they’re necessarily more efficient. “Electric models actually run more efficiently," he says, "but the higher cost of electricity makes them more costly to operate.”

Want it all? Get an electric heat pump.

[bboswell]

Couple of interesting facts from Consumer Reports:
Payback period for the investment in tankless:
Gas - 22-27 years
Electric - 12-20 years

Falls on its face from an operating cost/ROI perspective. Good luck getting 27 years out of a tankless water heater to recoup your “investment .”

Annual Energy Consumption Cost
Tankless
Gas - $195
Electric - $580

Tank
Gas - $245
Electric- $535

Not including maintenance.

“it’s worth noting that while gas water heaters are less expensive to operate, it’s due to the lower cost of natural gas and not because they’re necessarily more efficient. “Electric models actually run more efficiently," he says, "but the higher cost of electricity makes them more costly to operate.”

Want it all? Get an electric heat pump.

And this is why I only suggested tankless where a continuous flow, extremely low demand or install space dictate tankless.

[bboswell]

You can install a time clock on that 30 amp water heater circuit and you won’t have that problem

Not realistic for a family of 4 on 3-4 drastically different schedules.