jsl11 wrote:You may be able to extend the life of the water heater by replacing the anode.
Jeff
John Z wrote:Also, tankless is good in theory, but more expensive and not many people are trained to repair; parts have to be ordered, not usually in stock. With "endless hot water", showers can stretch longer using more hot water. I read these tips/info a few days ago on this forum. Someone provided a link to a site about saving energy and I was amazed at the reasons not to go tankless.
RustyShackleford wrote:John Z wrote:Also, tankless is good in theory, but more expensive and not many people are trained to repair; parts have to be ordered, not usually in stock. With "endless hot water", showers can stretch longer using more hot water. I read these tips/info a few days ago on this forum. Someone provided a link to a site about saving energy and I was amazed at the reasons not to go tankless.
Yep. One of the bigger "green" scams ever. (I do believe in green energy).
First there needs to be a definition of terms. There are heating boilers that have an internal or external heating coil, called a tankless, for making hot water. I am not a very big fan of these systems, which require you to leave your heating boiler up to full temperature for the whole year. A newer tankless water heater is a wall-mounted unit that only comes on to heat the water when a faucet opens looking for hot water. Because you are heating water as you need it, it is "tankless," also called instantaneous. They work beautifully and are made of stainless steel, so they last. The up side is that you could shower for 24 hours straight. The down side is that it makes a limited amount of water per minute, so two major uses of hot water cannot happen at the same time. They are perfect in smaller use applications, such as vacation homes, campers, or boats. They are very popular in Asia and parts of Europe.
The amount of water we can get out of these units depends on temperature rise, or how cold the water coming into the house is versus how hot you want the water to be at your faucet. The greater the temperature rise, the lower the flow rate. Maximum flow rate on most units is 2.5 gallons per minute. That's more than enough in real life, but less than Americans are used to. You can get water hot enough for dishwashers.
They are available in gas or electric, but I would only recommend gas at this point. The electric would need at least 14 to 15 KW (a lot of power), and the electric elements can scale in hard water.
RustyShackleford wrote:I just installed a 50 gallon Bradford-White conventional electric unit. It cost about $250 and I paid a guy about the same to install it, plus about $100 in random parts (including a subpanel we installed, in case I want to add a second water heater).
Keep It Simple wrote:Some of the posts here surprise me. In general, I always have found gas powered tanks to be cheaper in the long run. Obviously certain areas in the U. S. may have lower electric costs over gas, but I don't think that is the norm.
magellan wrote:
Also, as you pointed out, folks should be aware that electricity prices are wildly variable in the US. In some regions, each additional kWh of electricity may cost under 10 cents, while in others it might cost over 20 cents. There are places where people could pay over 40 cents per marginal kWh consumed, under heavily tiered pricing schemes.
RustyShackleford wrote:Yep. One of the bigger "green" scams ever. (I do believe in green energy).
...
It has an efficiency factor of 0.95. That's right, the most a tankless could save me is 5%. Meanwhile, the hot water lost in pipes (after you turn the faucet off) is typically (so I read) 15-20%.
Where did you find a 50 gallon Bradford-White for $250? Everywhere I checked, they were in the $500 range.
A tankless heater generally is of the instantaneous variety, as explained above. The energy savings is not in the water in the pipes, but because you're not heating up 40+ gallons of water 24/7 when you only need it for a few minutes a day ...
Combine this with a passive solar water heating solution ...
tyrion wrote:Tank water heaters are just fine, and probably a better choice if you have consistent hot water needs. Tankless might be better for infrequent (vacation house).tyrion wrote:Another data point:
tyrion wrote: If yours is in a location where a leak is going to get drywall wet, I think it's probably worth replacing sooner rather than later.
Keep It Simple wrote:tyrion wrote:Tank water heaters are just fine, and probably a better choice if you have consistent hot water needs. Tankless might be better for infrequent (vacation house).tyrion wrote:Another data point:
I think you meant to say that tankless would be best in both the above situations....yes? If you have consistent hot water needs, a tank heater will run out of hot water pretty fast. This is one of the major advantages to tankless.
K.I.S.
Keep It Simple wrote:Some of the posts here surprise me. In general, I always have found gas powered tanks to be cheaper in the long run. Obviously certain areas in the U. S. may have lower electric costs over gas, but I don't think that is the norm.
I also think going tankless has many advantages over a 40 or 50 gallon tank that must continually keep the water hot and runs out with moderate usage.
K.I.S.
tyrion wrote:Water heaters are basically the same, but you pay more for a longer warranty.
ThatGuy wrote:With regard to solar heating, any watt you don't have to use is a watt that doesn't have to be generated.
Particularly since you have to take into account the generation efficiency of that electricity at the plant, as well as transmission losses to your house. Consumer cost plays a big role, but it's not the entire picture as far as green energy goes.
RustyShackleford wrote:Yes, but I'm saying it makes more sense to just generate that watt if you can do so with a simpler and more versatile technology: PV solar versus solar hot water. PV is simpler because there's no moving fluids, and more versatile because the electricity can power things other than your hot-water heater.
RustyShackleford wrote:Very good point; the generation efficiency tends to be very high I think, because of the economies of scale and the huge financial incentive, but the transmission losses tend to average 50% I believe.
NY Times wrote:With greater efficiency, a power plant burns less coal and emits less carbon dioxide for each unit of electricity it generates. Experts say the least efficient plants in China today convert 27 to 36 percent of the energy in coal into electricity. The most efficient plants achieve an efficiency as high as 44 percent, meaning they can cut global warming emissions by more than a third compared with the weakest plants.
In the United States, the most efficient plants achieve around 40 percent efficiency, because they do not use the highest steam temperatures being adopted in China. The average efficiency of American coal-fired plants is still higher than the average efficiency of Chinese power plants, because China built so many inefficient plants over the past decade. But China is rapidly closing the gap by using some of the world’s most advanced designs.
wageoghe wrote:I've only seen one reference to hybrid water heaters (in Toons answer - the first answer in the thread). From a lot of reviews I have read, people seem to like them. For those that don't know, a hybrid water heater uses heat pump technology to heat the water.
Here is a link to GE's GeoSpring water heater:
http://www.geappliances.com/heat-pump-hot-water-heater/
A couple of notes:
- The "heat pump" extracts heat from the air and uses that to heat the water. There are two side effects: exhaust is dry cool air and water is generated (just like with an air conditioner).
- Due to the nature of the heat pump technology, is possible that having one of these in a conditioned space could "steal" some of your heat during the heating season. OTOH, if you have this in the garage, the garage could be slightly cooler and dryer (I don't know if it would truly be enough to notice).
- Because of the condensate, you must have a place for it to drain (floor drain, condensate pump, etc). If you have an AC air handler, washer, or HE furnace in the vicinity of your water heater, then you probably already have a mechanism in place for handling the condensate that is generated by the WH, since each of those appliances generates condensate.
- Because the heat pump extracts heat from the air, if your water heater is in a garage, the WH will be more efficient in a warm climate. If the WH is in an unconditioned basement, it could make the basement a little cooler (stealing what heat there is and trading it for cool exhaust).
It is possible to run in any of several modes from heat pump only to heating element only (and some combinations in between).
I am actually considering getting one of these the next time we need a water heater.
ThatGuy wrote:RustyShackleford wrote:Yes, but I'm saying it makes more sense to just generate that watt if you can do so with a simpler and more versatile technology: PV solar versus solar hot water. PV is simpler because there's no moving fluids, and more versatile because the electricity can power things other than your hot-water heater.
Eh? How is wiring electricity to the roof and installing either batteries or an inverter simpler than a solar water heater? Not only that, PV is not as efficient as direct heating. Fluids? You don't need refrigerants, take a look at this.
I just don't get this insistence that by adding more stuff in between, it's more efficient.
NateW wrote:How handy are you? It's actually not that hard to replace the water heater yourself. I replaced the gas hot water heater in my home and the replacement was a GE (yes, they make a natural gas-fueled water heater) from Home Depot for $450 with a 9 year warranty. Truck rental was $20 to get the heater home. You'll probably have to sweat solder the pipes and may have to adjust the gas line and vent pipe, if the dimensions of the new heater is different (mine was), but it's pretty straight forward.
I have read in some states (Texas being one) that by law only a licensed plumber can replace a hot water heater. It's odd, but the same state will let a car owner replace their own brakes.
--Nate
jayars35 wrote:An easy way to save on the operation of an electric water heater is put a timer on it. I installed one for a friend a few months ago. It was a simple wiring job and took less than an hour. We set it so his shuts off from 11pm to 5am.
runner9 wrote:We looked at tankless last year and thought about changing. Most quotes installed were around $2200-2500 hundred. Since our gas bill for water tank and dryer is about $23 in the summer and most of that is fixed cost regardless of use the payback would be quite a while.
Knock on wood, 22 years with the current tank style...
jayars35 wrote:An easy way to save on the operation of an electric water heater is put a timer on it. I installed one for a friend a few months ago. It was a simple wiring job and took less than an hour. We set it so his shuts off from 11pm to 5am.
DonM17 wrote:he suggested that it would not be a good idea because bacteria would be allowed to build up in the tank....he advised to turn the thermostat down a little but not to shut it off.
Temperature affects the survival of Legionella as follows:
70 to 80 °C (158 to 176 °F): Disinfection range
At 66 °C (151 °F): Legionellae die within 2 minutes
At 60 °C (140 °F): They die within 32 minutes
At 55 °C (131 °F): They die within 5 to 6 hours
Above 50 °C (122 °F): They can survive but do not multiply
35 to 46 °C (95 to 115 °F): Ideal growth range
20 to 50 °C (68 to 122 °F): Growth range
Below 20 °C (68 °F): They can survive but are dormant
The optimal temperature for Legionella proliferation in water varies between 32°C and 35°C, but it can easily proliferate at temperatures of up to 45°C. Usually, there is no growth above 55°C, and a temperature of over 60°C has a bactericidal effect. Thus, the WHO recommends that water be heated and stored at 60°C (3). However, studies in Quebec have shown, even when the thermostat is set at 60°C, a high percentage (approximately 40%) of electric water heaters remain contaminated because of the lower temperature, about 30°C to 40°C at the bottom of the tank. The probability of contamination will increase considerably if the temperature setting is lowered to 49°C. The risk of contamination is much lower for water heaters operating with fossil fuels, and is practically nonexistent for these heaters set at 60°C.
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