On demand hot water heaters
My 50 gallon hot water heater consumes about 900 dollars a year to heat water. I use propane since I live out in the boonies. I take one shower a day and other than that, I don't use hot water in the house. I use cold water to wash my clothes and my dishwasher can heat water with its electrical heating element.
The bottom line is that that tank out there is keeping a lot of water warm all the time when the need is very infrequent.
I've been thinking of installing an on demand hot water heater. It too would use propane but only heat water when I use it. The disadvantage for most people is that these things don't supply a lot of hot water unless you have a 1 inch input to the unit. The output for the least expensive devices is something like 3.2 gallons a minute. That's fine for me since I use low flow shower heads.
So, does anyone have any real experience with on demand heaters? I'm very interested in any personal experiences.
Michelle
The bottom line is that that tank out there is keeping a lot of water warm all the time when the need is very infrequent.
I've been thinking of installing an on demand hot water heater. It too would use propane but only heat water when I use it. The disadvantage for most people is that these things don't supply a lot of hot water unless you have a 1 inch input to the unit. The output for the least expensive devices is something like 3.2 gallons a minute. That's fine for me since I use low flow shower heads.
So, does anyone have any real experience with on demand heaters? I'm very interested in any personal experiences.
Michelle
Tags: demand, heater, hot, water
Views: 7
Replies to This Discussion
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Permalink Reply by mike on -
They aren't very different from oil fired heaters or any other type of boiler that uses a fluid coil to create steam. The old "steam gennies" that were used in shops are pretty much the same thing. I really like on demand water heaters. I have an oil fired water heater in the house I rent and that is pretty much the same deal. It saves me a lot of money compared to any kind of traditional tank water heater.
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Permalink Reply by RD Davis on -
No, I dont but, if you will take just some cheap water hose, and run it back and forth across the top of your house, and hook it to a water supply and the other end to your water heater, and fill the water heater from it when it is the hottest, you can turn your water heater off.
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Permalink Reply by Michelle on -
RD, I've thought of doing something like this, but I'd have to make sure that the system is drained when it freezes, I'd have to keep the system pressurized which causes some interesting problems with those steam generators up top (the pipe), and then maintenance would be an issue.
So, I thought that the on demand system would be the easiest to put in service with the best reduction in gas usage overall.
Michelle
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Permalink Reply by Henrik on -
Hi there,
think about an instant water heater, I know stiebel eltron is offering some of them, I have used such a system here in Germany and it works great. Stiebel Eltron USA: www.stiebel-eltron-usa.com
It only heats the water as you use it, fully automated. And the best is, you could even install a solar water heater to pre heat the water. If the water is hot enough the heater will not switch on. For a good compact solar water heater pleae visit: http://www.energybrightsolar.com/ (it is my invention and I am promoting it in the USA) Just have a look and please dont get me wrong. Ofcourse you are free to choose whatever system you like. I have installed a lot of solar thermals and heating systems. So please dont hesitate to contact me for further infos regarding any RE questions.
Have a sunny day!
Henrik
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Permalink Reply by Michael on -
Michelle
I hope the videos will help you, the site has more info.
Michael
http://www.youtube.com/watch?v=yh_-DUKQ4Uw
http://www.youtube.com/watch?v=V0M2GnQluJk&feature=related
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Permalink Reply by American in the D.R. on -
On demand/tankless hot water heaters, LPG or NG, are used in many others countries and are a proven product. I have two. Getting hot water IS NOT A PROBLEM. We have one that supplies two bathrooms and the kitchen. The other we have to heat our small pool in the winter... (while we save up and can get a real pool heater.)
The electrric ones that install at a shower head, don't work as well and I would recommend a good electrician to do the installing.
The unit does have to be vented, but installation is easy.
A simple Google search will get you lots of results.
Good luck.
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Permalink Reply by SJC on -
You could use a solar water heater in front of your propane heater. The solar heater is fed from the water main and it feeds the propane heater. The water in the solar heater is usually hot enough so that you do not use propane, but if not it still warms the mains water and saves propane.
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Permalink Reply by Gregory L. Smith on -
Michael, I do not believe that on-demand hot water heaters are the best value in longer terms than 5 years, because the costs for gas will continue to rise in Europe and Solar-thermal heating collectors can replace your entire heating and storage issues and are paid back totally within seven years even at higher altitudes. Israel and Florida both have companies that carry SEI certification for efficiencies above 50% of available light. That should be sufficient for all your needs and after the seven years are up, your heating costs go down to zero, excluding a twice a year check for cracks or damage due to expansion issues.
Remember that you entertain and have guests at your home from time to time. With a Solar system, you have two collectors producing approximately 130'F of heated water at a rate of 2 quarts (~2 Liters) per minute. And your 40 gallon or equivalent in liters (~142liters) can store a lot of water for showers and cleaning hands. Most installations use PEG tubing now, but the connections and lines on the roof will still be made of Copper alloy with special self-adjusting brass fittings to the tank. So even if you do not use the water, you will not be wasting the excess energy costs, since the energy is free.
Once the initial heating has occurred, your heated water is stored in your tank until you need it. If there is too much heat, the system can circulate the water through alternate heating coils for baseboard heating, or it can be circulated outside where the heat during the winter is dissipated or can heat a hot tub. (Should you want one!!) LOL!
During the summer, when heat is not needed, the units can be set to minimal heating and excess hot water can be used to run a cooling element that must have very high water temperatures to run efficiently. It uses a heat exchange fluid to heat sink and cause cooling inside the house.
In Spain, they have this system already in use and it produces both heat in the winter and A/C in the summer months. The cooling fluid is a form of antifreeze that removes heat and causes very cold water to be generated, which is blown by a fan and therefore warms the element while sending cold air into the local area. The water is then circulated up to the roof again and the heat reactivates the circuit of water flow around the cooling fluid. You should be able to find it on the Solar Energy group.
Cost for the two sets of collectors and the piping, fittings, and storage tank is about $7,500 or about SWF 7,200~. It still is a hunk of change, but it would solve your long-term problems and be free for you in 7-8 years, (Based on the $900/year cost of propane). Just Google, Solar Thermal and see.
Gregor Smith gregors@att.net
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Permalink Reply by Daniel on -
I worked at a campsite in my youth where the showers had On Demand water heaters, they are very efficent and easily maintained. I will be installing on in my house shortly, (as soon as it arrives). Depeinging on how often you use your hot water determins what the consuption is. I think it is a very wise investment, best of all, you dont need to worry about a tank busting a leak.
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Permalink Reply by David Sutton on -
I do not have any info for on demand hot water equipment But what I do have is extensive knowlege in making your exsisting system more effecient. A friend and I completely re-built a boiler room for a 800 unit apartment complex. Their fuel bill for one month was over $10,000 a month to operate After rebuilding we were told by the so called experts that it wouldn't work! We told them to prove us wrong while we fired up the system. At all hot water use points the temperature never dropped nor on the return loop which ran through the entire complex including the laundry room and swimming pool back into the boiler room. The temperature through out the system stayed rather constant despite the heavy usage. The experts were stunned! The fuel bill to run was less than half making the owners of the complex extremely happy. Now The experts have taken our Idea and use it on ships etc. with out our permission as well as copied in several journals. Your system to make efficient will require alittle expense up front yet will pay for it self over time. With your system living out in the country makes this easier. Before getting into anything, need to explain your current system which is like just about everyone elses. Useing a hot water tank which has inlet and outlet. when using hot water cold water is entering the tank at the same time which is cooling the tank off as you use. So you are actually getting about a quarter of the tanks hot water before getting cold, then the tank starts to heat up the entire tank. To make this more efficient you will need to preheat the water before entering the tank. This is done by taking soft copper tubing making a coil like a spring and placing inside the exhaust tube above the tank. Exhaust will heat the water before entering the tank so as not to cool it off so quickly. Second thing to do is to - yes get a second tank (same size as original, used for storage) along with a circulating pump for hot water. Take the hot side of tank one connect to cold side of tank 2, then remove plug in side of tank 1 and 2 (most tanks have plugs) connect tank 1 where plug was to circulating pump then opposite side of pump to tank 2. Just this alone will cut your fuel bill by about half. Tank 2 the hot side re-connect to house plumbing. you will not only cut fuel bill you will also have a full tank and a half of hot water to use. Now you can also make even better by making a solar water heater connected to this, cut your fuel bill even more. Also you can heat your entire home just using your hot water system only, called hydronic system. If you would like to know how and want more info let me know. Dave k2cokla@aol.com Ps. I live in the country my fuel bill average $30. month
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Permalink Reply by Tom Bailey on -
Hey;
I experimented with an electric version of the whole house on demand heater. It had 4 elements.
I built the house and was concerned with supply. So I used 1 inch line to the unit. I then ran 3/4 trunk supply lines. I then branched off with 1/2.
The problem, You could be in the shower and temp would be all over the scale. My truck lines were to big. I was pushing to much water. I was not about to replumb the house so I went to popane tank.
Next time I will reduce my trunk lines to 1/2 and 3/8 feeders. The shower heads will help, Tom
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