Electric Tankless Water Heaters

Our oil-fired water heater is getting temperamental and may have to be repl aced. (It turns off overnight and needs to be reset but not on warm nights, only on cold nights.) A friend said that they got an electric tankless wat er heater at her house and always have hot water when needed for the three people living there. Any opinions or experience with tankless water heaters ? They're supposed to be more energy efficient, from what I read, but the s avings alone don't seem to justify the investment.

Paul

Reply to
Pavel314
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Paul @@@@@@@@@@@@@@@@@@@@@@@@@

There are several things to think about. What part of the country do you live in ? If very cold water is comming into the tankless, it may not heat it hot enough for you. If you loose power often and have a generator, most will not run the tankless where your oil or standard tank electric heater will on a 5 kw or so generator. Your power feed from the main line may not be large enough and that will be an extra cost.

I doubt that I would put one in a new house and surely not in a house that it was not wired for.

If installing in an an older house it will take years to pay back for whatever you may save.

Reply to
Ralph Mowery

Per Pavel314:

20 years ago, everybody where we visited in Germany has point-of-service hot water heaters. Gas in the older houses, electric in the new. That would be a device at each faucet in the house.

Now, for reasons I do not know, they have gone over to a single tank-type heater for the house.

The only other thing I know is that, in the Dominican Republic where I went on a windsurfing vacation once, the shower-mounted electric heaters were referred to as "Widow-Makers".

Maybe somebody who actually knows something can comment.

Reply to
(PeteCresswell)

Paul

Reply to
BurfordTJustice

Per Oren:

Yeah... I didn't want to muddy the waters with my preconceptions.... but I think we're on the same square.... especially since I saw the wires sparking on the one I used.

Reply to
(PeteCresswell)

Tankless is way overhyped. The efficiency increase over tank type is small, standby losses just aren't that significant on any modern WH that is well insulated.

The drawbacks are significant - the need for a large and more expensive power or gas feed, the lack of any power / gas outage ridethrough, and also in reliability.

On the reliability front, since the tankless units have to run at a much higher BTU/hr rate than tank type, their elements or burners are under more stress and tend to not last as long as a quality tank type unit.

Additionally a tank type unit provides a reserve supply of potable water in the event of a water supply outage (municipal or well) that is always there even when the outage comes with no warning.

The one solid advantage that tankless types do have is in size, and for most that's not a significant consideration.

I've stayed at some places with tankless heaters, and unless they are absolutely top of the line units, there are issues with consistent water temperature are lower flow rates, i.e. when you're trying to get your shower temperature set correctly in the summer when the "cold" water supply isn't all that cold so you don't need as much hot water in the mix. Another issue with electric tankless units is their power demands is so high you can often see the cycling of their elements in slight dimming of the lighting in the room.

Reply to
Pete C.

to go tankless electric be prepared to install a new electric service, 200 amps just to heat water.. pllus your regular service, call your power company the neighborhood transormer may need upgraded too.....

tankless electric isnt a good idea

Reply to
bob haller

Have oil heat?

Check out

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and get an indirect fired water tank.I sace 37% to 39% on oil compared to the old boiler.

Mixed review on tankless. You need a lot of juice to power them.

Reply to
Ed Pawlowski

Can't install one here - maximum 150 amp service unless I pay about $8000 to upgrade the underground. Not happening!!!

Reply to
clare

Doesn't work with oil forced air - - - -

Reply to
clare

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These run on double pole 40 or 60 breaker. My concern would be cost of use. Electric is more pricey than natural gas, in many markets.

Reply to
Stormin Mormon

Yes, it can

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Reply to
Ed Pawlowski

replaced. (It turns off overnight and needs to be reset but not on warm ni ghts, only on cold nights.) A friend said that they got an electric tankles s water heater at her house and always have hot water when needed for the t hree people living there. Any opinions or experience with tankless water he aters? They're supposed to be more energy efficient, from what I read, but the savings alone don't seem to justify the investment.

I agree that the standby losses of the tank can't be all that much. In the summer, with a gas tank type, my total gas bill is typically $18. That includes whatever it takes to heat the water that is used, some gas grilling outside, and the standby losses. So, I'm guessing the loss part might be ~$5/mth.

I believe there are some that have battery ignition, so they will operate when the power is out.

Another advantage is they have an unlimited supply of hot water. Depending on the application and needs, that can be a major point.

If the service can even support a whole house electric. I would think they could make sense in warmer climates, where the incoming water temp doesn't get down to 40F in winter. It's all about the worst case temp delta and flow rate required.

Reply to
trader_4

But those don't support a whole house. They are point of use, ie enough for say one bathroom with a shower. And if you put 3 of them in a house, then you're back to the problem of the electric service needing the capacity to support all of them.

Reply to
trader_4

I didn't see if those were sink or whole house or what. Interesting that a whole house instant would take that much amps. Seriously, that could get very expensive, especially in a house with teen- agers who love endless showers.

Reply to
Stormin Mormon

Interesting that a whole house instant would take that much amps.

thats because the water MUST be heated instantly, with electric its impossible, without at least a 200 amp service, and in a worse case, with low incoming water temp, in wither you could need 2 200 amp tankless in series.

that would be 400 amps to heat water plus 200 amps for you normal home.

wonder how much the power upgrade will cost?

Reply to
bob haller

you could run a recurciliate line, either continious or activted by pussing a button so how water always arrives at the faucets immediately

Reply to
bob haller

thats because the water MUST be heated instantly, with electric its impossible, without at least a 200 amp service, and in a worse case, with low incoming water temp, in wither you could need 2 200 amp tankless in series.

that would be 400 amps to heat water plus 200 amps for you normal home.

wonder how much the power upgrade will cost?

Reply to
BurfordTJustice

Two points to that:

1 - The electric power that it takes to heat the water that you use is going to be the same, regardless of whether you heat it slowly in a tank, or fast in a tankless. The tankless has the advantage of not having the standy losses, but as I said they can't be that much. My whole gas bill is just $18 in summer. I would think the vast majority of that is heating water that is actually used. A related point that in many cases could make the tank type less expensive is that a lot of utilities have reduced rates for electric power during non-peak periods. With a timer, the electric water heater can be set to only come on when the rates are low. Even decades ago, I remember water heaters being on a seperate meter, with a timer, where you got a much lower rate for electricity. With move to smart meters, I would think that's the future for more people.

2 - With a tank type, it will put an upper limit on exceesive usage. Once the hot water is gone, it's gone.

Reply to
trader_4

SM1: Yes, fast or slow, a watt is still, uh, can't remember watt.

The tankless has the advantage of

SM2: More standby loss in winter, when the tank loses more heat.

SM3: Perhaps pilot lights? I've got a couple of those.

A related

SM4: I used to know a guy who had 82 gal water heater, which only ran night time, "off peak" side of the meter. Lived alone, so he didn't often run out of hot. No teenagers with bottomless showers (ha, ha).

SM5: Yes, the recovery rate and all. Good idea in some families. I split your two points down a bit finer, sorry.

Reply to
Stormin Mormon

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