Point of use/on demand hot water heaters

[Budweiser John]

After many years I finally have the luxury of a sink in my shop building.
Anyone have any recommendations for an electric point of use hot water heater?
Crusing the WWW there are a plethora of choices both 120V and 240V. I would prefer 120V.
Thanks in advance for any insights.
B. John

 

[EddieWalker]

Since you are asking about electric, be sure to run your numbers comparing what the cost savings would be compared to having a small traditional energy efficient tank heater. In every case that I've run the numbers, there is no savings with electric on demand water heaters compared to the cost of the unit and how long it should last before being replaced.

 

[prichard]

I can see cost benefit for rare use. Plus you never run out of hot water.

Bosch units were fairly affordable and well liked when I looked a few years ago.

 

[dmccarty]

Since you mentioned a sink, and that implies a relatively low flow of water, an on demand electric water heater might work. You have to look at the specifications for the unit and make sure that the heater can heat the water to the temperature you want/need. We looked at on demand electric water heaters for our house and it did not make sense for us. Years later we were talking with the plumber who helped build our house and he refuses to install them anymore. The reliability of the units with our hard water was causing too many problems.

For the house, we bought an 80 gallon water tank that uses very little power and was cheaper than the on demand units. An electric 120v on demand heater might well work for a sink but check the specifications, the temperature of your water, and the water's hardness.

Later,
Dan

 

[CobyRupert]

2 cents:
I don't know how the $ numbers compare on purchase price or lifespan/replacement comparisons, but there's got to be electrical savings, especially in a shop building where there may be zero usage for a number of days or even weeks.

I know with my tank heaters and my hard-water I think heated water sitting in them for extended periods, and going through heating and cooling cycles, causes more minerals to precipitate out of the water and shortens the life of the heat element when it is eventually buried in it. I'd be curious to see if minerals have as much of an effect on an on-demand heater.

Edit: Looks like above post answered that when I was writing this one. .

 

[4570Man]

I have a 220 volt electric one at a rarely used location. It works great in the summer. In the winter it can't heat water above warm. You could take a shower, but it certainly wasn't a nice hot one. It would have been fine for a sink. I can't imagine a 110 volt one with 1/4 or less of the power of the 220 volt one working.

 

[JRobyn]

Our basement in the new house is too low to be able to plumb a sink to the septic, but I had the builders run just a "daylight" drain out to the back and I installed a big utility sink next to the shop area. It is one of my most prized possessions! You will love, love, love it!

 

[buickanddeere]

After many years I finally have the luxury of a sink in my shop building.
Anyone have any recommendations for an electric point of use hot water heater?
Crusing the WWW there are a plethora of choices both 120V and 240V. I would prefer 120V.
Thanks in advance for any insights.
B. John

120V and 12.5 amp is going to make for a trickle slow dribble of wash water . You would be happier with a small insulated tank unit with a timer that only powers up when electrical rates are lowest.

 

[joefromga]

I have both the instant on and the mini-tank systems. They both work great and have advantages and disadvantages.

Instant is great but the smaller kw units are slow but plenty to wash hands and rinse rags. They are absolutely instant and work quite well. They do require heavier wire and that's expensive and labor intensive depending upon your location and attic/basement space etc.

The 2.5 gal tank is great because you get full blast water but it's only a small bucket full. So if you're using a sprayer or something you would want the pressure. . It's easy to plumb and plugs into 120v, not hard wired. It also looks cool being a tiny replicate of a real water heater.

There's no such thing as a free lunch.

They have whole house 36kw units. The wire costs alone are more than a regular tank heater. But boy, when you're running a hose outside in 40 degree weather and the steam is steady coming off the stream for as long as you want it sure is nice.

When it's 10 below outside your little instant heat will barely warm the water. The mini tank will, however.

 

[Stimw]

I put in a Rheem 7 kw (220 V) unit over a year ago. It was $179. on Ebay.
They do require heavy wiring to accomplish what they do.
There are charts to determine the size for usage needed and wiring listed in the ads.
I installed mine in a bathroom and have no problem taking a hot shower.
What the ads DON'T tell you is they must have copper lines 3' before and after because of the high heat output. I was lucky that I had copper plumbing!