Opinion/experience with tankless water heaters

IaLeo · Mar 20, 2015

I am bummed about washing my hands in cold water since chemo last year. 15 year old electric 80 gal water heater works well, but occasionally notice rotten egg smell, not yet consistent. Recently read that tankless water heating (close to fawcet?) would last 20 years. I recon it would take another 220 breaker and heavy wiring for each tankless heater, right? But for twenty years. I get no special elec. rate for water heating. Utility is pushing an eco-type using a compressor? and due to successful geo furnace experience, it looks attractive, but that is a lot more moving parts, relays, etc. which in my experience HAS been a small problem. And it does not give with quick on demand warm water. So has anyone used tankless heating and been happy with it and the bills? Thanks, Leo

hd6gtom · Mar 20, 2015

we put a small 1 in our processing plant. It supplies all the hot water needed. When I put 1 in the house it will be bigger.

JML755 · Mar 20, 2015

put in several in barns and 1 in a 1400 sq ft ranch. Works well in all but they're all natural gas so I can't speak to the electrics as far as consumption. I'd assume they get the water to the same desired temp but at what energy cost?

State of Jefferson · Mar 20, 2015

I've gotten good feedback on the newer one's.
Put one in a house last fall. Family of four, two daughters, big fancy shower with about 5 heads in it. Never run out of hot water. Natural gas bills have been under $50 a month all winter, that includes supplemental space heating in a 3200sf house.
If you are looking for just instant hot water at a sink, a re-circulation pump is probably a better option that an point of use heater.
I suspect a 15 year old tank-type heater is near the end of it's lifespan. Whole house tankless units cost about 3x what tank heaters do, they will pay for them selves, but I think you have to use quite a bit of hot water to justify one.

Ben

Steve@Advance · Mar 20, 2015

I looked into them a couple years ago. Got scared away, some good replies, some bad. Quickly realized that for a whole house application, the electrical requirements would be taking a 200a service to the limit. When the oven, range, and furnace were all on, it would be over the limit!

For a small undersink unit, it would be practical. Instant hot water, no storage, compact, long life. But I also heard warnings of calcification with hard water.

The odor you're experiencing supposedly come from a reaction with the anode rod in the heater. It's there to protect the tank from galvanic currents.

My solution was to buy a Rheem Marathon heater. It's a fiberglass tank, no anode needed, lifetime guarantee. The cost is about double over a standard heater.

The new standard heaters seem to be lesser quality. About all can be expected is 10-15 years. If you have to pay a plumber to install them, the Marathon will pay for itself quickly!

Two Dogs · Mar 20, 2015

I had an electric one. It may be okay for washing hands but for showers it is real exciting going from scalding to icy to scalding every time another faucet is operated in the house or the pump kicks on. I went back to a storage tank. TDF

Badger bob · Mar 20, 2015

Ialeo remove the cathode rod from the top of the water heater and the rotten egg smell will go away. ive done it and it works. Bob

oj · Mar 20, 2015

We put a tankless water heater in our workshop a few years ago, it works great for washing hands, but it does seem to struggle with the amount of minerals in our water, the water doesn't get as hot as it used too. I think I need to run some vinegar through it to clean it out.

Russ from MN · Mar 20, 2015

One of the bathrooms in our house is about 75 feet from the water heater, so I installed a 2 1/2 gal electric inline. It is 120V and works great, we get hot water very quickly, and when taking a shower there is very little change when the 70 feet of cold water enters the little heater.

Donald Lehman · Mar 20, 2015

My son installed a Rheem (sp??) and it only lasted three years before burning out. I believe it required two 220 circuits. It has been our only experience with on-demand water heaters, so I can't say if it is normal or a fluke.

M w J · Mar 20, 2015

I put 1 in my shop about a month age It is 220 volt and is great for washing your hands . The slower the water runs the hotter it will get when set at 150 degrees to cool of just speed up the hot water flow . I think it heats about 2 gallons per minute .

JBDyer · Mar 20, 2015

I have one I installed in April of 2008, It is a Noritz brand, I think it was made in Japan. Powered by propane. Has an adjustable electronic thermostat, excellent heater, absolutely no problems and you have hot water as long as you have gas and incoming cold water. I bought from a local plumbing supply house, cost about 3 times more initially than a conventional heater. We are a family of three (one teenage boy). Cant speak about an electric, but I suspect that the performance would be less than mine. JBDyer

504 · Mar 20, 2015

A gas one should have a freeze proof feature,my first one did not and after the third time the coil froze and broke, I replaced it with an electric one. Mine is a whole house model and requires three fifty amp breakers to make hot water. The under the sink models work great for instant hot water and run on 110V.

CenTex Farmall · Mar 20, 2015

We've had one for about 10 years now. It's a Bosch unit and runs on propane. No electricity required, only running water and you have hot water. Uses noticeably less propane than tank model it replaced and all plumbing on the unit is copper. Has a natural draft, 5" exhaust. The heat transfer is such that you can hold your hand in the exhaust directly above the unit and not be burned.

The temp is adjusted by changing the flow rate and the size of the fire.

It does require a large propane line for max BTU's.
Downsides:
Bosch has had some trouble with their units and I've heard of complaints on their fancier ones. Our water has a lot of stuff in it and after about 5 years the impeller on the spark generator broke. (Our water eats plastic!) I replaced it with a flashlight battery and back in business. I have had occasions where it didn't want to light and usually ended up cleaning the ground wire connection from the "brain" and it goes back to working.
The output temp is influenced by the incoming water temp and it won't heat water super hot the way a tank will. That's good and bad: little danger of scalding but no hot water for heavy duty laundry needs.

I would stay away from the combo heat pump/water heater; too complex for the job being done IMO.

1130Leo · Mar 21, 2015

We have 2 of them, one is a Bosch, one of the "fancy" units, hate it, installed it and have never been able to make it work correctly, bought a new tank heater... The other one is a very cheap propane unit at my cabin, uses batteries to ignite, works great, got it off ebay Alaska tankless water heater supply i believe.

ss55 · Mar 21, 2015

I'll second the suggestion to look into a recirculating pump as another option. The tradeoff is much lower installed cost, but less energy efficiency than a tankless water heater. A timer helps. Watts is one brand.

At 15 years with rotten egg smell, it may be time to replace the anode rod in your water heater.

JOCCO · Mar 21, 2015

I went with a bosh accustar whole house type runs on propane very happy with it. I would forget electric and use oil or gas and get a whole hose type. On demand so only uses fuel when needed. They were last I knew $5-700. If you got a unique situation like a long run they do have those under sink booster ones.

Tramway Guy · Mar 21, 2015

High iron content can cause rotten egg smell.

Charles (in GA) · Mar 21, 2015

It seems that everyone is recommending tankless units that replace your existing heater. You will have the same problem with cold water until the hot water can get to you, so a centrally located tankless will do you no good for what you want, which is "right now" hot water.

The smaller electric units will still require lots of electricity. What kind of capacity does your circuit breaker panel have?

I know a 13K BTU electric will work good for a kitchen or bathroom sink, marginal for a shower. For a shower you would need a 18K or possibly a 22K unit. Everything above the 13K watt unit requires two or three double pole circuits, and additional runs of wire to power them. This is due to a restriction in the electric code that limits heating circuits of any kind, to a max of 60 amps, so they have to run multiple circuits to power the larger tankless water heaters.

A house with a couple or three electric units could easily take up a good portion of one side of your breaker panel.

Charles

buickanddeere · Mar 22, 2015

One of these days we are going to install a 120V 1/2 gallon "tank heater" under the kitchen sink for similar reasons.

Bryan inIowa · Mar 22, 2015

In the process of installing on demand nat gas water heater. This one will supply house needs as well as in floor heat. Not sure of all the specifics on it yet. Pretty sure it has recirculating systems too . Pricey , $3000, trading this out with plumbing co. I do service work on their fleet of trucks. But saves from having to buy another boiler for in floor heat system.

GordoSD · Mar 22, 2015

Remove the anode from your heater and cut about 2/3 of it off. Reinstall. How many people are living in the house? How many showers a day are taken. I'm guessing you could get by with a 40 gallon tank.or less.

Opinion/experience with tankless water heaters

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