Don’t you have gas on-demand heaters in the US? That’s the standard in Japan, and that’s what I described above. Electricity is too expensive.
I have a gas demand heater at home and it is sheer bliss!
The shower takes no longer to heat up than getting the water from a tank, the flow is excellent (you can just about knock yourself over in the shower at full pressure) and it mixes just fine. All of the hot water in the house comes from the same source; a single exterior mounted Rinnai Infinity model. I think these folk are a local NZ company… if other demand heaters are as bad as sailor’s then perhaps they should export.
I haven’t had a demand heater before, (this one just came with the house when we bought it 18 months back), but I’d happily now put one of these in at any new house I was moving to.
I think that it really depends on the quality of the system that you buy. I have good and bad storage systems, and good and bad on demand systems. (I move a lot.)
The best overall was an on demand system. It had electronic controls in the kitchen and bathroom. You simply set the control at the temperature that you wanted, and opened the tap to the pressure you wanted. Anything from a trickle of unheated water to a blast of water damn too hot for anything was available. The electronics took control of everything.
On average, I’ve found gas demand systems to be slightly cheaper to run too. I assume it is because water is not heated when you don’t need it.
I just realised that the electronic system I had was the same as the one that Apollyon has. (Maybe a different model if you don’t have the controls Apollyon.)
Mine was in Perth, Western Australia, so if that NZ mob can get them that far, they can at surely get one to the US.
Nope, electronic control in the kitchen (set to 50 celcius for safety).
I lived in Japan with a demand heater for my kitchen tap, but had no shower at all - rather, I had a lovely gas-heated bathtub. My experience with the kitchen tap pursuaded me that although it might save a little bit of gas (always an issue in Japan, where gas has to be imported), the only real reason to have one was for space considerations. And I’d have gladly sacrificed a square metre or so to have a proper tank water heater.
For non-Americans - most U.S. households have a large, tank water heater fueled either with gas or electric. In apartment buildings, there may be an oil-fired tank (common in New York). “On-demand” is all but unknown.
Just to add my 2 cents: A friend of mine has a gas hot water on demand tankless heater and has no problems with it. He has stated that he has saved quite a bit of money over the water heater he previously had (in monthly gas costs).
There were issues in the installation though. The amount of BTU’s put out by the on demand system required some modifications to the exhaust system. The heater put out so much heat when operating that he had to put a whole new pipe to his chimney.
Sorry this is so vague, I’ll try to get more details tomorrow…
Oh, one more thing… My friend (and I) live in Denver and he owns a circa 1950 house.
For what it is worth…
I should probabaly admit that the combi boilers that I have owned and hated so much were older models than the conventional model that I now own and am happy with, so the efficiency comparison may not have been entirely fair, but the general feeling amongst my circle of friends (mostly families with young children, - requiring lots of hot water) is that conventional boilers are better.
Only one of the four engineers that visited my house to quote for installation of our new gas central heating system suggested a combi boiler and we rejected the idea simply because we have a three-storey (town)house with the boiler in the garage on the ground floor, but the bathroom and a space for the hot water tank on the top floor; with a combi boiler, we would have to run out that entire cold ‘leg’ of water from the garage to the bathroom before the hot water started coming out, against piping it a few metres across the top landing from the tank.
(sure, the conventional boiler has to heat the indirect loop which also goes all the way from the garage to the tank, but it only does that once or twice a day).
FWIW, American homes are generally larger and so can sacrifice the space needed for a water heater tank. The tanks are either gas or electrically heated. The nice thing is that water is a pretty decent insulator; that is, it holds temperature fairly well, not cooling especially rapidly once heated. So once you get a tank up to the desired temperature, it tends to stay there with not too much energy expended.
I would therefore think that US type tank units are more energy efficient, as to flash-heat (very rapidly --as in instantly) heat water has to be rather energy intensive.
Homes in other countries tend to be smaller (shockingly so by US standards), and so placement of a water heater can be an issue. I imagine that land costs, the governments’ desire to collect taxes on energy, etc. can be involved in the local decision to recomend or mandate on-demand water heat units over tanks.
For you all who’ve never seen one, they are vertical tanks, needing about the same amount of space as a standing person. …And in/out water pipes, energy hookups, etc.
I formerly lived in Northern CA, where there was a pretty high mineral content in the local water (it came from wells). A water heater would last about 8 years at best there, because the minerals would accumulate on the tank walls and heating elements and promote corrosion as well as decreasing the efficiency of the heating. Here in the eastern US (DC area), they tell me a water heating unit lasts at least 15 years.
One other thing for those who are unfamiliar with the tank heaters: they usually have a “sacrificial anode” in them; a post (copper or copper alloy, I do beleive) put in from the top, designed to corrode before the rest of the tank. So when you finally have to scrap a tank unit, you drain it out to reduce the weight and in so doing get a lot of blue-green oxidized copper goop.
It sounds like gas is the way to go if you want the tankless. Unfortunately, I don’t have natural gas available where I live. I heat with wood and solar.
I am thinking about going to propane for my heat. But where I would put an on demand system does not allow for any venting.
Foiled again.
Most on-demand heaters in Japan are located outside the house, usually just outside the bathroom. Not very pretty, I admit, but it does solve the space and ventilation problem. I think I’ve used a propane heater which worked pretty well. (Could have been kerosene - I know that house didn’t have natural gas)
We lived in Holland from 1968 to 1970, and the only water heater we had was a demand heater in the kitchen, which was also piped to the bathroom upstairs. It was impossible to take a shower, because it could not heat the water fast enough to get a decent flow. We bought a plastic bathtub (the house had only a shower), and filled it slowly to get enough hot water for a bath. It worked ok for doing dishes, etc. I suppose it would be possible to get one that had enough heating capacity to be able to take a shower, but the one that came with our house definitely did not.
I hope nobody minds me jumping in here, and this may be offsubject, but…
I spent a year in Brazil and many showers there have wires (many of them bare) that go into the water directly below or into the showerhead. I don’t really know how it worked but thought somebody here would know what it was.
p.s.
If you’re tall like me and get your head too close to the shower head you get a little shock!