Tankless on-demand water heaters are popular in Japan.

Thread Starter

Glenn Holland

Joined Dec 26, 2014
705
Mod edit:
This thread was split from a old thread -- On Demand Water Heater.



Tankless on-demand water heaters are popular in Japan.

They're mostly used to fill Japanese "Ofuro" bath tubs (a hot tub for one person). The flow rate is lower so they may not be suitable for use with American showers or baths.
 

GopherT

Joined Nov 23, 2012
8,012
Tankless on-demand water heaters are popular in Japan.

They're mostly used to fill Japanese "Ofuro" bath tubs (a hot tub for one person). The flow rate is lower so they may not be suitable for use with American showers or baths.
What motivated you to post useless information on a 5-year-old thread.
 

Thread Starter

Glenn Holland

Joined Dec 26, 2014
705
I was originally posting on the subject of "Water on Mars" and I saw this thread at the bottom of the page.

So I thought What the Hell - I'll throw in my 2 cents anyway.
 

DickCappels

Joined Aug 21, 2008
7,303
Mod edit:

* Some text removed for clarity *

The flow rate is lower so they may not be suitable for use with American showers or baths.
Not entirely accurate. I am an American and I shower using an on-demand (tankless) heater everyday. I assert that on-demand heaters are suitable for this American's shower :) Granted, the shower heads are designed for a low flow rate.

These are useful for showers in the tropics because the water temperature doesn't have to be raised very much. My heaters draw only about about 5 kW.
 

shteii01

Joined Feb 19, 2010
4,644
They are sold in US. My father was thinking of getting one, I think he thought, at the time, that the water consumption will be lower. Anyway, he did not get it, not sure why.
 

MikeML

Joined Oct 2, 2009
5,444
I built an apartment into my airplane hangar for visiting flying friends that is not used very often. I didn't want to keep a 50gal water tank hot 24/7 on the off chance that it might be used a couple of days a month, so I used a natural-gas fired tankless demand hot-water heater. With that system, you could take a hot shower that lasted all day on a day when the outside winter temperature is 0degF
 

Brownout

Joined Jan 10, 2012
2,390
I built an apartment into my airplane hangar for visiting flying friends that is not used very often. I didn't want to keep a 50gal water tank hot 24/7 on the off chance that it might be used a couple of days a month, so I used a natural-gas fired tankless demand hot-water heater. With that system, you could take a hot shower that lasted all day on a day when the outside winter temperature is 0degF
Do you think that could completely replace the domestic water heater for a normal size (~2000 sq ft, 2 bath) house? I'd sure love to get rid of my bulky water heater and replace it with 1 or 2 of these small units.
 

MikeML

Joined Oct 2, 2009
5,444
Do you think that could completely replace the domestic water heater for a normal size (~2000 sq ft, 2 bath) house? I'd sure love to get rid of my bulky water heater and replace it with 1 or 2 of these small units.
The unit I used was fed with a 3/4" Natural Gas line. It was something like 250,000 btu. No way could you do it with an electric heater, or with bottled gas.

I wouldn't do it in a residential situation where you turn on the hot water tap more that twenty times a day. Modern gas tank heaters are very efficient, if you can overcome stupid county regulations that you always have hot water at every tap in the house all the time (recirc. system).
 

Brownout

Joined Jan 10, 2012
2,390
Modern gas tank heaters are very efficient
Efficiency is not the reason I might want to do this. I have a small area in my basement for two bedrooms. The water is right in the middle of the basement and makes it difficult to move around in between the rooms. I've thought about just relocating it, but can't figure out a place it could be and not still be a nuisance. If I had a smaller water heater, I could make it all work.
 

nsaspook

Joined Aug 27, 2009
8,293

loosewire

Joined Apr 25, 2008
1,686
Tank less water heaters are coming to U.S.fast. Your common model will

require more insulation according to new standards already to go in effect.

Check it out with your plumber,the old models will not fit in the same space.

Ready to remodel your heater closet.
 
Last edited:

sirch2

Joined Jan 21, 2013
1,029
If I am talking about the same thing these (called condensing combi boilers over here) are the preferred option in the UK. I've put in two now and they are easier to install, required less space (no tank) and are more efficient.

I would also disagree about flow rate. The typical UK installation had a header tank in the loft (attic) which was typically about 4 or 5 feet above the top of the shower head. The combi boiler is connected directly to the mains supply and so in most areas has significantly higher pressure.
 

strantor

Joined Oct 3, 2010
5,540
This thread was born out of a statement, not a question. It was a statement necroposted onto a discussion that ended years ago.
What followed was a series of other disconnected statements.
I think that if furbies could access the internet and post in forums, this thread is what their discussions would look like.


"bee bee bee bop tankless water heater"
"tankless water heater beedle dee bop!"
 
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