I researched the tankless water heaters last spring when I was building my pool house. After research, I went with the natural gas Rinnai. Besides saving a considerable amount of space, this water heater indeed puts all the standard tank based water heaters to shame.
When hot water is not required, it uses zero energy. When hot water is needed, it will provide plenty of hot water to run two showers at once as well as having plenty of additional hot water available to the sinks. When taking a nice long shower, you never have to adjust the water temperature like you have to do with all tank water heaters. You know, when taking a long hot shower, you constantly have to keep adjusting the temperature to keep it where you want it. This is because you are draining the stored amount of hot water in the tank and the overall temperature of water in the tank is constantly dropping. Not to mention that if you have a large family, it is quite possible to run out of hot water. With the Rinnai tankless water heater, I can take a week long shower and the temperature will not fluctuate at all during the shower. You will never run out of hot water.
I have a family of seven. In our main house, we have two fifty gallon water heaters. Even in the summer, when basically the only natural gas used is for the water heaters, the natural gas useage is high. That is because I'm keeping 100 gallons of water hot 24 hours a day 7 days a week whether I need hot water at any given moment or not. This is a huge waste of energy. This is becoming especially true with the price of natural gas going up in huge percentages.
After mentioning how much we liked the Rinnai tankless water heater we have, a business associate of mine changed his two fifty gallon water heaters to the Rinnai tankless models. He also has a large family. His natural gas useage dropped by nearly 60% the first month. Needless to say, I'm making arrangements to remove the old extremely wasteful dinosaur tank water heaters in my home and have them too replaced with the Rinnai tankless water heaters. Oh yes, besides the energy savings, the reported average lifespan of the tankless water heaters is about 20 years. Then, it is repaired, not replaced. Each component in it is easily replaced. The average life span of a standard tank water heater is 10 to 12 years. Then, the entire unit has to be completely replaced.
If you do some research, you will find that only about 1% of the rest of the world uses the extremely inefficient and wastful tank water heaters we use here in the United States. The supply house where I bought my first Rinnai this last spring told me that their sales of the Rinnai tankless water heaters has gone up over 8000% over the previous year. Yes, that is eight thousand percent. Evidentially I'm not the only person who has discovered that having a tank based water heater may be one of the biggest wasts of energy in the normal house.
The supplier even said that he is having some success in explaining to people that nobody sells a "hot water heater". Nobody needs to heat "hot" water. What you want is a water heater, not a "hot" water heater. /forums/images/graemlins/wink.gif You may want to remember that when you call to ask about a tankless model.
Here is a pic of what the entire unit looks like. I don't know if you can see, but there is a digital panel on the left of it where you program in the exact temperature you want your water to be.
