Tankless water heater?

[MushCreek]

Anyone have any experience with them? In recent years, the selection has really grown, and prices are dropping. I'm thinking about getting an inexpensive one for the shop as a test to see if I want one in the house.

The shop has a full bathroom, with a shower. The ones I'm looking at are rated at 1.5 GPM, which I think would just cover the shower, depending upon the season. I'm in SC, so our incoming water doesn't get super cold. The drawback is that it draws nearly 40 amps; the advantage is that it only draws when in use. It will mostly get used for washing hands; the shower seldom gets used. I just want to see how much capacity a shower would really need.

Lowes has a lot to choose from. For instance, they have a very small Bosch unit that's only $200. I may pull the trigger and give it a go. Thoughts?

 

[M-technik-3]

Is that small unit designed for a kitchen type application? I have two in our two houses a rinai and a navien.

The rinai works of street NG and the Navien is converted to Propane. The Navien is far mor efficient but we knew that purchasing it on the second go around plus for the size of the house we needed the bigger unit. The Rinani works great but shower, washer and say the sink no way can it keep up. It's also louder with the blower unit. The Navien, is quiet and we live in the country so things like that you hear.

Could put a washing machine in your shop so not to bring chemicals into your home machine. You say it takes 40 amps so it's electric powered vs gas or propane? I have only seen those as under the sink units in apartments.

 

[B.S.A. (ret.)]

We switched out to a Rinai Nat. Gas (Model RL 75) about 2 years ago to replace a 50 gallon Gas hot water heater. Gas consumption dropped by about 25% and I see no noticeable difference in performance. Yes, as M-technik-3 says above, the Rinai does sound a bit like an idling jet engine, but it is located next to my furnace in a closed room of the basement so no big deal. I am pretty much all NG where I'm located, so can't give you any advice on electric units.

 

[M-technik-3]

Yeah my rental property aka my home in a month is all NG, Clothes drier, H20,Furnace and Stove plus garage, makes for inexpensive utilities bill.

 

[B.S.A. (ret.)]

M-technik-3: Not trying to hijack, but I used to live in southern Berkshire County. You anywhere near there?

 

[MushCreek]

No natural gas here. The small units are mostly intended as point-of-use, but I think it will work fine for the shop. I have a small tank-type for the shop, but the problem with those is that the water sitting in it gets funky because it gets used so seldom. I don't leave it on for that reason, so when I want it, I have to wait for it to heat up.

As I said, this will be sort of a trial balloon to see if I would consider them for the house. We have a standard, old-school cheap water heater now, and it's by far our biggest energy draw. Our house is very tight and energy efficient, so the water heater is almost an embarrassment. When I built the house a few years ago, I considered a heat pump water heater, but the good ones were too much money, and the cheap ones were garbage. I'm going to see how I like the tankless, see what's new in heat pumps, and also see what it would take to add a solar collector to the roof.

 

[garagelogician]

First costs aside, your water quality is probably going to the biggest factor in how well one would work for your application. Are you on city water or do you have a well? Hardness is the big one, though other minerals and water quality conditions can impact it as well.

If you do get one, purchase from a well-established manufacturer, and maybe contact some companies that service that brand to get their input on common problems, etc. Troubleshooting these can be a pain in the **** if you don't have access to competent techs, unless you are really good at DIY and can get your hands on the factory manual.

I used to be in the HVAC design business (ground source heat pumps, primarily wellfield design) but I dabbled in the equipment side of things as well...so I was real hot on the efficiency train for awhile. We had a geothermal testing trailer that had two condensing boilers (basically a tankless water heater on steroids) that ran on propane...and we had a fair amount of problems with them.

I've since gotten back into the civil engineering field, and my interest has waned. When my wife and I purchased our house last year, I did some due diligence to see if a tankless would be the right choice for us. Natural gas is pretty cheap in our area, and the payoff is just too long, especially when you factor in the maintenance and possible problems that come with the increased complexity.

 

[handymancanfixit]

Home Depot sells EcoSmart brand and they have gotten some good reviews. They come with a lifetime warranty. From the research I have done, sizing it correctly is crucial. When sized correctly, you have an endless supply of hot water. My detached garage has a toilet, hand sink and slop sink downstairs and a shower, toilet and hand sink upstairs. I am going with the EcoSmart 18kW model because I only have one shower. They are also self-modulating, which means they adjust the power requirement to suit the incoming water temperature. They need a 1 hour vinegar flush annually to dissolve any minerals/scale/buildup. Installing service valves makes flushing them a breeze. Most of the reviews indicate that the payback is pretty much instant, especially since the cost of the electric units has dropped to nearly the price of tank type electric water heater and the power savings are as much as 60%.

 

[calif phil]

I don't want an endless supply of hot water, wife and kid would take twice as long showers as they do now.

 

[bob15]

I've had a LPG Rinnai tankless water heater for close to 10 years, with zero complaints. I would recommend one to anyone. And yes, I have a well and hard water (with a softener).

 

[ducksface]

How does a hot water circulation pump work with a tank less?
Spec calls circulation pump on hot circuits, maybe not on tank less?

And if not, it's three gallons of cold water before our lines clear out the lines....
This shouldn't affect your shop, but I'm interested in how it works in a large house... Multiple points to use tank less?

 

[wait4me]

I have a natural gas powered Takagi in my current house. No complaints.

In my previous house I had an 18kw (3.5 gallon/min) Ecosmart electric. I liked it, but did have to switch to lower flow shower heads. Filling a bathtub took an eternity if I chose to.

I would be skeptical that you could run a shower and be pleased with the performance.

Also, since someone mentioned ecosmarts lifetime warranty, understand that it requires that the water heater be installed and certified by both a professional plumber and professional electrician. Without their signoffs the warranty is invalid.

 

[kbs2244]

I have heard the trick is to not over size them.

They depend on incoming water temp to know if they should turn on.
If the out put floe isn't high enough they can cycle on and off resulting in "pulses" of hot water.

Something not nice in a shower.

 

[lakeroadster]

.. three gallons of cold water before our lines clear out the lines....
This shouldn't affect your shop, but I'm interested in how it works in a large house... Multiple points to use tank less?

We have a Noritz natural gas tankless, just one, in our small home. Yes it takes a while for the lines to clear out.. but that isn't any different than an old school tank style water heater.

On larger homes, yes there are multiple tankless units.

 

[ducksface]

We have a Noritz natural gas tankless, just one, in our small home. Yes it takes a while for the lines to clear out.. but that isn't any different than an old school tank style water heater.

On larger homes, yes there are multiple tankless units.

Thanks.

 

[nbpt100]

I have a Navien in my house for both heat and hot water run off of nat gas. It is hard to say how much it saves year round as it depends on how cold the winter is for an apple to apple comparison.
In the summer I have seen my usage go down to about 1/3 of what it normally was when that is only the hot water and the stove consuming gas. To give some idea of the hot water savings. It is nice that you never have to worry about running out of hot water between washing cloths, dishwasher and showers.
My only complaint is that it takes a minute to get hot water in the kitchen if it was not just used. It is the furthest distance from the unit. You waste a bit more water.

 

[abachman]

I have a Bosch that has been great for whole house use, 3 1/2 bathrooms. Take as long as you want in the shower and the water stays the same temperature the whole time. There is a slight lag to get the first hot water, but just about the same as from a hot water tank. It is not instant hot water.

 

[mrobins297aaa]

I have this one in my barn that I run off a 20# propane tank

 

[Showkey]

We have a Noritz natural gas tankless, just one, in our small home. Yes it takes a while for the lines to clear out.. but that isn't any different than an old school tank style water heater.

On larger homes, yes there are multiple tankless units.

I have a gravity loop recirculation on a conventional tank heater.........2-3 second wait for hot water at any faucet in a ranch style home.
My total all in water heating cost is $10.00 per month with NG. Absolutely no maintenance costs and 20 + year life expectancy. With 50 gallon tank I never run out of hot water with any thing close to normal use.

I have a condo in Florida witha electric tankless where it takes 4-6 minutes of running the shower to get hot water. The unit demands yearly service even with just occasional use from deposit in the water. Makes the meter spin off the wall.

I would never ever put a tankless in full time home with NG.
High install costs especially on a retro fit.
High maintenance costs.
Long wait times for hot water.
This wait time plays havoc with the washer and dish washer.
Gas and water and sewer bills can actually go up due to more use witha family.
The ROI with tankless is never reached.

In the OP sitution in shop I can see the proper sized tankless unit to give hot water and good solution to the shop need. A small unit met for under the sink is not going to supply water for washing cars or the floor. Maybe ok for a sink and hand washing.

Another family member has cottage witha propane tankless and it works fine in the occasional use but also experiences the high maintainance with well water.

 

[fastjohnny]

For a garage, even with a shower, a 7 gallon mini water heater would do the trick. Cheap to buy, cheap to run. I've had this solution for 2 years with good results, in line with my tank water heater in home, over 50' away.

https://www.amazon.com/dp/B0148O64JE/?tag=atomicindus08-20

 

[MushCreek]

I have a 10 gallon mini now. If you go easy on the temperature, you've got about 10 minutes in the shower. As I said, it gets funky, because I'm not using it very often. The shower head in the barn is 1.5 GPM. It's not the end of the world if it's only warm instead of hot. From my research, I'm already talking myself out of a whole-house one.

I'd be doing annual service anyhow, because I shut off the water to the barn in the winter, so I purge the lines. It wouldn't be much more work to flush it out. Our water is city, and pretty decent.

 

[jives]

We have a propane Bauxi Luna in the house that runs both radiant floor heat and hot water. It is about 4 years old, after replacing a trouble prone QuietSide unit. Uses well water, no mineral issues to date, but it is fickle. Requires yearly (or more) maintenance from HVAC pros to keep it from exhausting unburned propane.

 

[wssix99]

Anyone have any experience with them? In recent years, the selection has really grown, and prices are dropping

We have a single combined tankless Navien boiler that provides hot water to our house (3 baths and 2 half baths) and also 2000 sq foot of radiant heat. It works great and we have no major complaints.

How does a hot water circulation pump work with a tank less?
Spec calls circulation pump on hot circuits, maybe not on tank less?

And if not, it's three gallons of cold water before our lines clear out the lines....
This shouldn't affect your shop, but I'm interested in how it works in a large house... Multiple points to use tank less?

It works just fine, but I think its essential for a large house. We have 5000 sq feet and put in the recirculating lines "just in case" we needed to add a pump. We figured out pretty quickly that we wanted it. Fortunately, we were able to just pop the pump in without needing to add any plumbing.

We put our unit in the middle of the house with the expectation that it would speed up the flow everywhere. In theory, that would have been fine, but our plumbers put in a lot of 1" copper through the house to combat pressure drops so, we end up having to move a lot of water to some areas to get things to heat up. The recirculating pump will save us a lot of energy in this regard.

I say "will", because it's still a work in progress. This thread is spot-on with regard to the approach for a recirculating pump with these systems: http://www.garagejournal.com/forum/showthread.php?t=280892&highlight=tankless BTW - We found that the way to go is with an adjustable thermostat recirculating pump and NOT the a variable speed model! (We had a challenge finding good resources on the topic other than how to hook these up, so we had to do some experimentation...)

Some sort of remote control is needed for the recirculating pump and is the most elegant and energy-efficient solution for a large space. My wife ran the pump 24/7 for a few weeks (not thinking...) and we burned through $40 of gas and electricity for the exercise. All the hot pipes also acted as a radiator and raised the temperature of the house by 4 degrees! We have a lamp timer on the pump now so we have fast hot water in the morning and at night. This works well, but we can be more efficient. I think we may put in some remote control timers with a home automation system so we can command the water to circulate and pre-heat as we get ready to take a shower, work in the kitchen, etc.

On larger homes, yes there are multiple tankless units.

We chose to do one large unit instead of multiple smaller units and I don't regret it because of the maintenance...

The maintenance is a bit of a PITA. The unit needs to be taken apart once or twice a year to have multiple filters and screens cleaned out and the heat exchanger also needs to be de-scaled. The later exercise involves isolating the system from the house, (with valves) and then using the service ports to hook up a circulating pump to run cleaning solution through the unit for a period of time.

 

[MartBella]

I have the same size house and number of occupants. I bought the Navien NR-240. It supplies plenty of hot water for us. I wish I bought the A model though. Our dishwasher does not work well with the tankless unless we run the hot water periodically throughout the cycle.

Otherwise it is fine even with the coldest incoming water. I am in Ontario.

 

[SJW]

I have one.

It's reliable, but I have two issues:

* It takes about 30 seconds for the hot water to get to my shower, which means that water is either down the drain or I have to catch it and use it to water the plants.

* Despite getting the appropriate size unit, when my wife turns on the water to brush her teeth, the water in the shower still goes cold for a second.

There's nothing I could have done about the location, but if I were doing it again, I would get the next higher capacity unit.

 

[Leevon]

I am putting a crossover water heater by HTP in my new house currently, 6 bed 4700sf. It's basically a hybrid high efficiency unit. They use tube exchangers and high temperatue with mixing valves etc for the endless water supply. Well, there is a recovery period but my friend has the same unit in a 6,000 sf house with 4 kids and hasn't found the end of the hot water yet.

http://www.htproducts.com/RGH75100.html

 

[wssix99]

Our dishwasher does not work well with the tankless unless we run the hot water periodically throughout the cycle.

Why? What dishwasher do you have? All the dishwashers I've ever seen use only cold water and then have their own heating element inside. (Presumably for this very reason.)

 

[wssix99]

* Despite getting the appropriate size unit, when my wife turns on the water to brush her teeth, the water in the shower still goes cold for a second.

Oral hygiene is important. The family shouldn't skip this or blame the water heater. If the problem happens instantaneously (and is transient) when the faucet goes on - it's a problem with the mixing valve in the shower.

If the problem is transient and happens with a 30 second delay from the faucet coming on, you may just need to adjust the flow sensor or a pressure sensor on the water heater.

 

[59 wagon man]

your incoming water temp in the winter can probably get down into the 40-50 degree range requiring almost a 40 degree rise to feel lukewarm. 40 amps isn't much. the smallest I would look at would be something like and I hate to say this but a titan n120. it is sold under many brands including rheem. it is 60 amps

 

[My Old Tools]

How does a hot water circulation pump work with a tank less?
Spec calls circulation pump on hot circuits, maybe not on tank less?

And if not, it's three gallons of cold water before our lines clear out the lines....
This shouldn't affect your shop, but I'm interested in how it works in a large house... Multiple points to use tank less?

They have a small tank built in.

 

[rburke65]

It pulls 40 Amp. and it’s natural gas fired?

 

[Steve W.]

I see the thread is a couple of years old, but has some recent responses.

I have a Bosch NG unit in the house. 3 bedroom, 2 baths, just the two of us plus occasional guests. House was built in 1957, plumbed entirely with 1/2" copper, so I looked for a heater that uses the same. Also wanted no electric ignitor (wife's request), so we ended up with the Bosch, which uses a turbine wheel in the water line to generate the spark to light the heater. Works well. Only problem so far (9 years) has been a failed safety switch.

Out in the shop, it's only a half bath and a deep sink, so not much need. Did not go for the expense of running gas to the shop, so went with a Rheem electric. Again, using 1/2" copper. Yes, it draws 50+ amps when running, but it's seldom on for a full minute, so financial impact is minimal.

The only problem with the idea of tankless is that they require a minimum flow to stay lit. If a guest closes down the hot faucet a bit to cool off the mix, there is a chance that they go below that minimum. If that happens in the shower, it's hard to convince them to turn the hot valve OFF, then ON again. We try to warn them ahead of time, but it always happens.

.

 

[dcg9381]

I have a small 3-4 GPM unit. Actual GPM depends on how cold the water is initially, but it's good enough for washing dishes, washing machine, or a shower (probably not all at once). I didn't want to deal with eating up all the amps for an electric version, so we went with propane. Like the poster above - I didn't run gas to the shop, I just mounted a 100 lb "portable" propane tank (about $160 from home depot) outside of the shop with a decent sized regulator. I probably have $500-$600 in the entire setup including the gas lines, etc.

Ours is "indoor" with a stainless steel vent exiting to the outside. Mounted on an exterior wall. Condensation is through the vent pipe also. Not terrible to install (I'd never done one before)


For the house, we'll be using larger propane version and I'm planning on using a push-button recirc switch in the master bathroom as we are somewhat water restricted in terms of available water.