Mini water heater / tankless thoughts?

[Ron_J]

I am getting ready to install a utility tub in my garage and trying to decide if hot water is worth it. I don't have a bathroom, just a sink and hose bib. I don't want to take up any more floor space than necessary, so I'm thinking about a small 2.5 gal water heater or a tankless to put under the sink.

Anyone have experience or recommendations with these?

 

[Jackfre]

Let's see, Jan/Feb in PA. Need to wash something in the sink? Nah, water is to cold. Sure, do it!

 

[bamawildcat]

I put a 2.5 gallon Steibol water heater in my workshop. I have it on a smart switch, so it stays off during the week and I turn it on through the weekend. It is very nice to have hot water, and it is on a shelf under the sink. Come winter time, I disconnect it and turn it upside down to drain the water to keep it from freezing.

 

[infinkc]

i would go with a tankless point of use if just for a sink.

 

[redmondjp]

Go with a small tank. If you plan on using that sink to clean parts, 2.5 gallon tank is too small - we have a 4 gallon underneath our kitchen sink right now and it barely makes enough hot water for one rubbermaid container inside the sink of dish water and the rinse water is lukewarm. I am sitting a few feet away from a 12-gallon tank that I am going to install in the dead corner space underneath the counter, which should do the trick.

If you use a tankless unit, with a high-flow faucet on that utility sink that will flow 3 GPM or more, you're going to need a good-sized tankless unit to get the water much over 100 degrees F, assuming incoming water temp of 50 deg. F or so. I would recommend a 6-8 gallon tank on a 120V 20A circuit instead.

If you do decide tankless, look very carefully at the temperature rise that it can produce at the flow rate of whatever faucet you install. It may do 75 deg. temp rise, but only at 1GPM (gallon per minute), and if you put a 3GPM (which is typical of a laundry sink) faucet on it, you won't get hot water, only warm.

 

[pmiranda]

For handwashing, a 110 tankless with a low flow faucet is plenty. If you need to fill that sink for washing something, you need a 240V unit. Look up the user guides and they'll say how many GPM flow and temp rise each model will do.

 

[joey1320]

Have you seen the "point of use" water heaters?

https://www.homedepot.com/p/ATMOR-3...lagrZmguxJANeu8kepsaAkZXEALw_wcB&gclsrc=aw.ds

 

[Ron_J]

Have you seen the "point of use" water heaters?

https://www.homedepot.com/p/ATMOR-3...lagrZmguxJANeu8kepsaAkZXEALw_wcB&gclsrc=aw.ds

That looks perfect.

I really don't see me needing hot water for more than just washing up a bit.

 

[Leaflessshadetree]

I have a tankless point of use. It works fine as long as I keep the flow low. At very low flow it gets very hot. I can have a good flow that is plenty warm for washing my hands.

 

[wes73]

I have a 10 gallon point of use installed on a shelf above my sink. Plumbed into the sink and 2 hose bibs. It's nice to be able to wash cars early spring and late fall with a bucket of hot water.

https://www.homedepot.com/p/Rheem-P...t-Of-Use-Water-Heater-XE10P06PU20U0/204318373

 

[sberry]

For the same price can get 8500 watt vs that puny ******.

 

[wes73]

For the same price can get 8500 watt vs that puny ******.

Correct, but sometimes you have to just fit the need.

 

[nadogail]

I have the small tank type water heaters under the sinks in both my garage and workshop.

I appreciate the convenience of having heated water on demand.

 

[redmondjp]

If you need to fill that sink for washing something, you need a 240V unit.

Not true. A 120V tank heater will work perfectly fine, so long as it has sufficient capacity. They make 120V tank heaters that are 20 gallons. For a shop sink that will be occasionally used for cleaning, and for making a bucket of hot car-wash water, a 6-8 gallon tank will do it. Also, the temperature setting makes a big difference in how much hot water you will use as well (as you are tempering it with more cold water when it starts out hotter, so you are using less of the hot water).

Those Home Depot tankless units linked above are all very low flow rates and simply will not work satisfactorily for a utility sink that flows 3-5gpm. You are going to need at least a 20kW unit to get proper temperatures at the typical flow of a utility or mop room sink fixture.

I spec these things for a living. We have ongoing complaints on our latest job in the bathrooms with 0.5gpm faucets that have properly-sized tankless heaters feeding them. That flow rate is SO SMALL that it takes close to 2 minutes for the water to get warm at the tap. Why? The thermal mass of the piping and the faucet ***** the heat right out of the water - you have a tiny amount of hot water flowing, and piping and a faucet that is room temperature which takes the 120 degree water right down to 75 or 80 degree water until the faucet itself gradually heats up. It's the same problem you have trying to solder on a really large part with a very small soldering iron - the thermal mass of the large object ***** the heat right out of the small iron.

 

[dcg9381]

these?

I have a shop that we've decided to use for "temporary residential" - kinda got advanced by Covid. We have a sink, a washing machine, and I can run cold/hot/mix to an exterior hose bib as water pre-heat for an RV - basically "endless shower" in the RV versus the factory 6 gallon water heater.

I didn't want a traditional water heater - too much space. I looked into electrical tankless, but the amp requirement was really high... I ended up buying a "fairly cheap" (under $300) LPG (propane) tankless water heater by Eccotemp.

Note, I've never done residential propane or any real plumbing...

I believe mine is rated for 3 GPM. It's got a stainless vent that goes through the wall. I installed it in a few hours. It's powered by a 100 lb "portable" propane tank that cost about $130.

It works great. How well they work is really a factor of two things - how cold your incoming water is and water flow...

We get about 3 months out of it in cold months out of $70 worth of propane using that and a propane dryer... And I don't know how long - likely 6+ months in the summer when we're not pre-heating the water to the RV very much.

 

[sberry]

I wish they made so much easy to find stuff when I started some of this and I have collected since, a few things took me a couple of tries. I will agree this can be done on 120V. I got to mirror what Redmond said, hand wash 6 to 8 gallons, its enuf to fill a bucket.
I got a bud or 2 has 120/20 gallon in their houses, granted they live in a dump but by themselves its enough for 1 laundry, I modest shower and doing some dishes. Its not charging fast but they dont care.
I saw some poorly designed utilities in a nice building recently. It was all an after thought. Depending on scenario might even come up with a heated cabinet under sink, could act for some warm storage and to be able to keep the plumbing live.
Yes the building is a place to pull cars in but its for humans too and a raceway for the utilities. My Bud had a simple garage he really should have put an addition on, hoist bay and utility room he could have kept heated. Warm hand wash is a super great feature and really works so well with oil and grease.
I never leave with dirty hands. I dont even look dirty until I work about a week in the same cloths, I dont gotta roll in it, wipe on pants and shirt. I got a bud, on the floor all the time, rolling on the floor and I get knee pad and do the same work kneeling. He teases me about being scared of dirt but I find it so much easier to take a minute, wipe it, wash hands than try to clean it up after smearing it everywhere and dont want it on my cloths getting in cars cconstantly.

 

[sberry]

I am about 20 ft from hot with this. I used 1/2 pipe instead of 3/4 to speed it a little. My office is about 5. I use it a lot, there is a little delay but live with it. Lemon dish soap in a dispenser and paper towels. If they are just wet I reuse them on grease but a towel is cheaper than cleaning. I know many got their favorites, but simple paper towel, simple soap and hot water.
I realize blue and shop rags are tuff er but I like this best, don't got to be stingy. Hot day, in a hurry I got a shampoo there, can stick head in the sink and grab half a dozen paper towels and done in 2 minutes.
I replaced the sink once, it was just dirty. It takes a couple minutes but I convert them from laundry to kitchen faucet. I dont have to fill a lot of buckets, I do take out the restrictor but I like back of the hand operation when dirty. I can turn it on, by the time I get some soap the hot is there. I can get by without the fancy foot control.

 

[Innovate1]

Have you seen the "point of use" water heaters?

https://www.homedepot.com/p/ATMOR-3...lagrZmguxJANeu8kepsaAkZXEALw_wcB&gclsrc=aw.ds

That's VERY low flow and their map is very optimistic about supply temps. I am near St. Louis and our winter tap temp is a lot lower than 57F. I found a place that lists the average at around 60. I put in a 20 gallon tank. About the same price as a smaller unit and put it above the bath so it doesn't take up any floor space.

 

[sberry]

I have 2 sinks in shop, one in mechanic bay. It has small water heater.

 

[mcspeed]

Not true. A 120V tank heater will work perfectly fine, so long as it has sufficient capacity. They make 120V tank heaters that are 20 gallons. For a shop sink that will be occasionally used for cleaning, and for making a bucket of hot car-wash water, a 6-8 gallon tank will do it. Also, the temperature setting makes a big difference in how much hot water you will use as well (as you are tempering it with more cold water when it starts out hotter, so you are using less of the hot water).

Those Home Depot tankless units linked above are all very low flow rates and simply will not work satisfactorily for a utility sink that flows 3-5gpm. You are going to need at least a 20kW unit to get proper temperatures at the typical flow of a utility or mop room sink fixture.

I spec these things for a living. We have ongoing complaints on our latest job in the bathrooms with 0.5gpm faucets that have properly-sized tankless heaters feeding them. That flow rate is SO SMALL that it takes close to 2 minutes for the water to get warm at the tap. Why? The thermal mass of the piping and the faucet ***** the heat right out of the water - you have a tiny amount of hot water flowing, and piping and a faucet that is room temperature which takes the 120 degree water right down to 75 or 80 degree water until the faucet itself gradually heats up. It's the same problem you have trying to solder on a really large part with a very small soldering iron - the thermal mass of the large object ***** the heat right out of the small iron.

I totally agree. I was talking to a plumber friend and he said he prefers tank type water heater. All the hype about tankless is hard to understand. I had them in my old house and experienced exactly what you described. I went tank type in the new house and it delivers much hotter water with greater speed. . Much better.


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