Electric Tankless Water Heater

[Rockin RK]

My SIL is building a new house and wants a tankless water heater since the house will be all electric so will the water heater. She will be the only one living thereo no herd of kids to worry about. Does anybody use one or can educate me on the good and bad points of these.

Thanks in advance

Randy

 

[ShenandoahJoe]

The big difference from a tanked water heater is that you can't set the output temperature to whatever you want. With a tank, you can just heat it longer and it gets hotter. In a tankless heater, the critical factor is the difference between the input and output temperature. Be careful that you have the right sized heater for how cold the water gets in your area.

 

[srossman]

I looked at them briefly, but determined that they take a lot of electricity to run. I think it would require a 50 amp breaker in the box to run just one, and the temperature rise wasn't as much as I would have needed. Went with a propane tank-less instead and I really like it.

 

[stratton]

I heard the electric ones are not as efficient as a gas or propane. But still are better then a tank heater. As long as you don't have 5 teenage girls taking long showers every day then tankless is the way to go. Otherwise its just not sensible to use a tankless if they are constantly running. When i was considering a tankless i remember coming across an article that compared the cost savings with them to a tank heater. I believe a family of 4 or 5 with one average shower a day is the limit as far as cost savings with a tankless. Anymore then that it would be better to go with a typical tank heater. The tankless uses a huge amount of energy for a short period of time.

 

[nikdfish]

When we replaced a 16 year old water heater this spring, we went with the GE heat pump water heater (Geo-Spring?). Although it includes resistance elements for backup / supplimental heating, I set it for e-heat mode which prevents the heating elements from ever coming on. We have never run short of hot water. We got it on sale & even adding in a 10 year full coverage warranty we paid more than a hundred less than the list price...

I believe that only heat pump or solar pre-heat systems can really significantly reduce water heating costs. I think the only significant pluses for tankless water heaters is that they take up less space & don't have a tank as a potential point of failure - current well insulated tank models don't lose that much heat on a day to day basis...


Nick

 

[F1520]

Same here. Researched this with my neighbor recently. Electric tankless water heaters take a large amount of current to run. What size service does the house have? Is there also a well pump on the property?

The smallest Stiebel Eltron electric tankless water heater I could find requires 220v/50A and specifies a 60A breaker.

You can research several different brands at pexsupply.com and there are some specs on the different models here: Stiebel Eltron | Tempra Series Technical Data

 

[stratton]

Consumer reports say that it may take 22 years to recoup the cost of putting one of these things in. And the life expectancy is around 20 years, haha nice

Are tankless water heaters a worthwhile investment?

 

[srossman]

When we replaced a 16 year old water heater this spring, we went with the GE heat pump water heater (Geo-Spring?). Although it includes resistance elements for backup / supplimental heating, I set it for e-heat mode which prevents the heating elements from ever coming on. We have never run short of hot water. We got it on sale & even adding in a 10 year full coverage warranty we paid more than a hundred less than the list price...

I believe that only heat pump or solar pre-heat systems can really significantly reduce water heating costs. I think the only significant pluses for tankless water heaters is that they take up less space & don't have a tank as a potential point of failure - current well insulated tank models don't lose that much heat on a day to day basis...


Nick

Nick,
Is that a geo-thermal unit that you put in, or something else?

 

[nikdfish]

Nick,
Is that a geo-thermal unit that you put in, or something else?

No it's not geo-thermal, it pulls heat from the surrounding air. We have it installed in the basement/workshop space. It makes less noise than a dehumidifier. Power consumption is less than resistance heating as long as the ambient temp around the unit is above 45F. Even if unheated & unused for a while, I don't believe that space ever drops below the mid to upper 50's. Power draw in e-heat mode is like 550 watts.


Nick

 

[dmccarty]

We looked at electric tankless water heaters when we built our house 6 years ago. We have a nice big 80 gallon tank heater. :laughing: We bought the best insulated tank we could find.

The problems back then with electric tankless water heaters:
- Cost.
- Getting the output temperature from the supply temp could be a problem depending on flow rates.
- At the time the electric tankless heaters did not seem to work for what we needed or thought we need.

So we went a bought a good quality tank. I still would like to put in a solar hot water system but that seems iffy money wise on the payback.

Later,
Dan