BEST Electric Whole House Tankless Water Heater.

Discussion in 'Tankless Water Heater Forum' started by John Ross, Jul 22, 2019.

  1. John Ross

    John Ross New Member

    Joined:
    Feb 7, 2017
    Location:
    Tampa Bay Florida
    I live on the West Coast of Central Florida. The area has very Hard Water. My home has a water softener.

    I'm looking for advise from a Professional Plumber.

    I about two or three months I want to replace my Kenmore tank water heater that was installed in 2006. I would like to replace it with a Electric Tankless model to free up some space. No option for Natural Gas.
    I could install LPG but it would be quite expensive as the tank would have to buried.

    • PLEASE advise the BEST whole house Tankless Water Heater by Brand and Model Number.
    • It would be great it the water heater was WiFi so I could monitor it on my cell.
    • Also, do these units require maintenance, and if so what are they and can a very handy DIY person that knows electrical and plumbing do the maintenance?

    Thank you in advance for your advise,
     
  2. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Caveat: I don't have a plumbing licence- not a professional plumber. (I specify mechanical systems, but don't install them except on some of my own projects.)

    The Stiebel Eltron Tempra series has the best reputation for reliability. The model number depends on how much power you need, so how many bathrooms are you supporting with it?

    You're probably looking at a Tempra 20 or Tempra 24 if it's anything other than a 1-bedroom 1-bath kind of house, bigger if it's 3 baths. If you have a big soaker tub to fill even the Tempra 36 would make tub filling an exercise in tedium, and a 6 side spray deluxe shower would bring it to it's knees.

    When you figure out how big it needs to be, check to make sure you have adequate capacity on your electrical service (200A might not be enough for both the tankless and the rest of your house). Don't cheap out on wire sizing- when in doubt go a size fatter, not the bare minimum size for amperage & length. At max flow these things draw more than most peoples' entire house.

    Wi-Fi is not a feature on tankless water heaters. (What would you want to be monitoring anyway- temperature? Modulation level?)

    The only period maintenance a tankless normally needs is de-liming, which won't be an issue for years (decades?) unless your water softener craps out.
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. John Ross

    John Ross New Member

    Joined:
    Feb 7, 2017
    Location:
    Tampa Bay Florida

    Dana,

    Thanks for responding. The reason I put, "I'm looking for advise from a Professional Plumber", is they know which models have the most trouble, and which are the most reliable.

    You said WiFi is not a feature on tankless water heaters.
    I have put two examples below showing it is available on GAS tankless water heaters.

    Rinnai Tankless Gas water heater.
    https://www.rinnai.us/tankless-water-heater/accessories/wifi

    Navien Tankless Gas water heater.
    https://www.navieninc.com/downloads/npe-a-s-brochures-navilink-consumer-brochure-en

    As for maintenance, most units including Tempra will tell you, "to ensure consistent water flow, it is recommended to periodically remove scale and dirt that may build up at the filter screen in the unit". This is another reason I'm looking for advise from a Professional Plumber as they service these units all the time.
     
  5. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Only plumbers who install a large number of electric tankless units would really have a clue as to their relative reliability, and I suspect very few plumbers catering to the single family home markets have installed more than a few dozen total, and not a wide range of vendors & models at that. Engineers who spec them for mid to large multi-family applications get much better feedback on reliability, since there can be dozens per project, and they'll hear about it if they start to crap out.

    Electric tankless water heater pretty rare (and rightly so) in my cold-climate location, but I trust the opinions of mechanical contractors in cooling dominated climates, who seem to lean toward Stiebel Eltron over lower priced competition. There may be other decent units out there, and perhaps someone with good experience with those can chime in.

    And what value do those WiFi apps add to the gas tankless heaters? Seriously- what were you thinking was worth monitoring?

    I was close to laughing out loud at Rinnai's rationale for going WiFi on the water heater:

    ----------------

    Key Benefits:
    • Control and Convenience: Control your Rinnai Tankless Water Heater from a smart phone or tablet.
      • Adjust temperature
      • Register product via QR code or serial number
      • Activate recirculation (if you have a recirculation system)
    • Remote Diagnostics and Monitoring Alerts: Remote diagnostic tools provide detailed system information.
      • Select a monitoring dealer
      • Receive automatic maintenance alerts
      • Enable monitoring dealer to manage system performance and provide faster service
    • Faster Hot Water: With the addition of Wireless Demand Recirc accessories, hot water can be obtained at the push of a button.
    ----------------

    With most tankless water heaters you "set and forget" the temperature, and if you need an app to do it or register the unit the money might better be spent on psychiatric help to overcome the phone-addiction. There is a lot more going on inside a gas tankless, and even there the value of any of the Wi-Fi features is dubious at best. Turning the temperature down while you're away does nothing for you, the way it might be with tank type heater, and you can't use it with utility demand-response programs without taking cold showers, unlike with tank type water heaters, where power can be interrupted for minutes or hours without dramatically or noticeably affecting hot water performance.

    Putting Wi-Fi on an electric tankless appears a solution in search of a problem, but maybe somebody will find something useful that isn't already solved better or more directly by some other means and 'splain me why it's really a good thing to have. Electric tankless units are extremely simple beasts compared to their modulating fossil-burning counterparts, with almost nothing much that ever needs diagnosing. There are no moving parts, and very simple, self contained controls, not much to monitor other than temperature, no fuel or water pressure, no flame detectors, etc- they are extremely elegant in that respect, unlike the complexity of the sub systems needed to make a modulating gas burner work safely and efficiently.

    On the Navien gas fired combi boilers there can be at least some use in having remote Wi-Fi monitoring over the space heating/boiler side if you haven't already tweaked in the outdoor reset curves to satisfaction, or for some reason it starts short-cycling on heating calls when you're not there to adjust the many parameters at the front panel to tame it, but even that's something that shouldn't need much attention once fully commissioned.
     
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    FL has the chance of an electric tankless working. If you end up with a long cool or cold spell, you might be temporarily end up with cooler water than you wanted. Your momentary power draw when heating will be huge - more in the range of a small factory than a typical home. Make sure that the utility company and your electrician realize what you are planning. Not done right, your neighbors will all know when you're using hot water as their lights dim.
     
  7. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    ... or when your house catches fire. I wasn't kidding about being extra-conservative on wire sizing- even a 12 kw water heater is a HUGE load compared to most other loads (unless you have a 10 ton air conditioner or something.)

    The most recent multi-family residential building spec I became aware of using electric tankless hot water was a 20+ unit building full of studio & 1-bedroom single-bath apartments in Salt Lake City, where I believe each unit got a Tempra 12 (a bit marginal IMHO, given the wintertime water temps.) The cost adder of pulling all the fat wire for water heaters was daunting enough that on subsequent projects the developer went with other solutions. In a single family home the wiring run length would normally be shorter than the average for that multi-family, but it's still not cheap. Even a 12KW 240VAC unit with 50' of wire would at a minimum need 6 AWG wire (but 4 AWG would be better). At 50' a 24KW heater would need an absolute minimum of 1 AWG (0 AWG would be better.) If cheaping out on wire the amount of power available at the tankless drops, and the more power ends up being dissipated in the wire, heating it up.

    In some areas the utilities are lobbying for including "demand charges" to residential rate structures, in part to deal with the infrastructure cost of serving homes that use very little net energy due to self-generated power from rooftop solar. If that ever becomes true in your area an electric tankless becomes a liability, since demand charges are usually based on the heaviest-use 15 minute period at any point during the billing period. A 10 minute shower at 10,000 watts getting billed at $5 per peak kilowatt can add $35 or more to the bill, even if your average use over the billing period is less than 1000 watts. (I heard of one utility in AK that assesses $8/kw for residential demand charge.) One utility in my area managed to squeak that by the utility regulators for solar customers in a rate case a few years ago, but it later got shot down by the state legislature. That's not to say it won't ever happen though.
     
  8. WorthFlorida

    WorthFlorida Black Belly Whistling Ducks

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    I noticed this post when it was first listed and also living in Florida, a tankless unit only may give you some floor space, nothing else. Here is the URL for the Tempra 20 unit that Dana suggested and I'm only using this as an example since other tankless systems of the same wattage will not make anymore hot water than any other manufacture.

    First look at the wattage, 19.2 killowatts when it is powered on, then look at the amount of water per minute @105 degrees for 75 degrees which is the average water temperature in Florida. That seems impressive. Your Kenmore water heater is 4.5KW and some maybe 5.5KW maximum. The spec calls for a 2-40 amps breakers. If your home was built before 2000, most homes have 150 amp service unless a 200 amp service was specified by the original purchaser and there may not be room to expand one additional double breaker. Something you need to look into. A permit and a license electrician would need to wire in the tankless system. The electrician may cost as much as the labor for a plumber to install.

    If you search this forum under the tankless system, there are a lot of problems associated with getting hot water. There is a minimum amount of water flow needed before the electric elements kick in. Plumbers normally do not want to work on these after the install because there are no mechanical parts and maybe only if there is a leak. The rest of it is all computer, programming and other faults you can get with any computer based systems. If one does he or she may perform a reset then call up the manufacture. A Geek Squad tech probably would have a better chance at get it to work than a plumber.

    Another is maintenance. A standard electric water heater is virtually maintenance free. A tankless as you found requires descaling. If it is not descaled the heat transfer from the elements to the water decreases. If I'm not mistaken and by other posts, the Tampa area has much harder water.

    A co-worker of mine had his water heater inside his laundry room replaced with a tankless system. One day when no one was home and no water running, an internal thermostat had a failure and was a run-a-way. It got so hot that the solder joint at the copper pipe connection got soft and the connection blew apart. He came home with 4" of water through the house and was nearly six months before he could move back in. He did install another tankless unit but moved it to the garage.

    This all started with you stating that you need the space. Tankless systems may be good but I do not think it will deliver what you expect, maintenance free and reliable.

    Living in Florida for thirty years I don't see any advantage to go with a tankless unit other than gaining about 2 square feet of floor space. We have about the warmest water in the country so cost wise it is low since we also have very low electric rates. If the water heater is in the garage it doesn't lose that much heat through the insulation since the garage is alway hot. When I go on vacation, I switch off the water heater since the breaker panel is in the garage. Since 2012 electric water heaters had to meet new energy standards and all of it was done by increasing the insulation with closed cell foam. When I want to replace my current water heater the hybrid unit, such as the Rheem look very good. It is a conventional water heater plus a heat pump on top of it. Sure it is taller and not much wider but it will air condition my garage to a point. When the 212 degree engine from the wife's car is parked in the garage, I'll be recovering that heat and the cost of heating water is about 1/3 of a conventional electric heater.

    https://www.e-tankless.com/stiebel-...6whEP6nCbMdncDBK24aWx4sJ6WF5GCjhoCJ3EQAvD_BwE
     
  9. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Sure, Tampa has hard water, but he reported in the first lines, "The area has very Hard Water. My house has a water softener". The water softener should all but eliminate the need for periodic deliming if maintained and up to snuff, which I pointed out at the end of my first response. Without the water softener it might need descaling multiple times per year at Tampa's hardness levels, depending on how much hot water is used, and what temperature it's set to. (Setting it as low as possible reduces the rate of lime deposits, even at the higher flow that setting it low would require.)

    Even though they're more expensive, heat pump water heaters tend to be the better deal in hot humid climates, since it lowers the latent cooling load for the house, putting that latent heat into the water as sensible heat, using about 1/3 the amount of total power as a tankless. A dozen years ago when the product type was new it was a bit risky, but now most vendors are on to their third & fourth generation products, which are much quieter, more reliable, and more efficient than the first generation GeoSprings, et al. Even if installed in in an open carport where it doesn't help the cooling load for the house at all it's still 3x as efficient as a tankless (more than 3x as efficient during the summer.)
     
  10. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    In other words, you've got nothing of substance to say other than "click here".

    How much per click are you making on it? :rolleyes:
     
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Tankless systems are not particularly new...they've been in use outside of the USA for decades which is one reason why many of them come from Asia. But, one also has to consider that few places on earth are as decadent with their water use as the USA, so for much of the USA, they don't always work as well as you may be led to believe. If you really need lots of hot water fast, you may be in a situation where you need multiple units (not all of them can get ganged together easily), and that can put a HUGE load on either the electrical supply or even the gas supply.

    In the next 5-years, you may also start to see more demand charges from utilities. This can raise your base rate up considerably, even though your average use may not be all that much, negating much of the cost advantage (which, in reality, may not be true at all what with the utility upgrades, the higher cost of the unit, and required maintenance). While they may also be pretty reliable, the average plumber won't stock parts, may not have any training on repairing them, and, you may not find any parts on the weekend, or maybe even during the week readily available unlike most any simple tank.

    So, do not go into a tankless install without some significant research. While they can work, they do have some significant differences from a conventional install and operation.
     
Similar Threads: BEST Electric
Forum Title Date
Tankless Water Heater Forum Best options for electric tankless unit Sep 21, 2013
Tankless Water Heater Forum Best tankless unit for a poolhouse Dec 21, 2018
Tankless Water Heater Forum Best Solar Pump ? May 26, 2016
Tankless Water Heater Forum Tankless not flushed for 10+ years!! Best way to flush? Nov 24, 2015
Tankless Water Heater Forum BEST location for tankless? Oct 14, 2013

Share This Page