Electric Tankless questions

bluefitness

I know there isn't much difference in energy savings going from tank to tankless electric heaters. I own a condo that I visit only once or twice a month, so I was thinking it would be a good option. I am only going to install an 18kw 2.3gpm model. I live in Florida, so the groundwater isn't cold. My questions primarily involve brand and gpm.

What brands do you recommend? Here are the ones I am looking into:

-Powerstar A115 (Bosch)
Seems to have bad reviews or mixed reviews

-Stiebel

-Rheem
Not sure if they make it in a size I want

-Ecosmart


I am leaning towards the Ecosmart. It uses standard heating elements that are easily replaced and comes with a good warranty. I have never heard of this brand, however.


My next question involves gpm. Is 2.3gpm sufficient for a whole house system? I'm guessing it would be since some showers only use 1.5gpm shower heads. What type of temperatures can I expect if 2 showers are running at the same time? I believe the ground water is 65 degrees.

TarheelTerp

18,000W / 240V = 75Amps
Do you have anything even close to this much electricity to spare in your panel?
Is your panel close to the WH location?

This utility requirement (electric or gas)...
is the #1 reason why tankless end up not being installed as a retrofit.

bluefitness

The unit requires 2 40 amp breakers. I would need to add one more 40 amp breaker and run 8 gauge wire. I will use the existing 40 amp breaker/wire that was used for the tank water heater.

AllanJ

Don't forget, it's two 40 amp breaker pairs, not two 40 amp single breakers. Your panel and feed cables need to be rated for 100 amps (@ 240 volts) as a bare minimum.

You need to do a new load analysis to be sure that your panel will meet code after installing this.

If the home is unoccupied for more than a week, you already save a lot of energy by turning off the water heater (set the small knob to pilot or the large knob to vacation for gas heaters).

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joecaption

I toyed with the same idea at one time, when checking for prices one place I checked was Amazon.com. Bring up the brand your thinking about buying and go to the bottom of the listing to look at reports from people that have bought the same model.
I was very surprized at how many people hated some of the brands and had removed and replaced them.