If its going to be a week for parts to arrive or  the next appointment for the only good service man in   50 miles is next Friday,   you are  sunk....sunk...sunk

3.  READ THE FINE PRINT BEFORE YOU BUY ONE--- every brand  states  in their very fine print...

The heating coil should be flushed out with a de-scaling solution and cleaned  "periodically " by a qualified service tech to maintain good performance,   if  the heating coil limes up due to hard water,    this  VOIDS  the  warranty!!!

Before you  buy one,   ask what it will cost  to clean the heating coil in your tankless water heater and how often this should it be done??  

Ask  what will happen to your hot water    FLOW RATE   if the tankless unit is not de-limed      "periodically". 

 How often does   " periodically"   really mean??  

Will you attempt to  "de-lime"  your tankless unit yourself  once,  or twice  per year??  

Does  $125 --$150  per trip  2+  times a year to de-lime your tankless heater sound very economical??

Remember to factor in this    "de-liming service"  to your yearly energy savings!!

http://www.complaints.com/2007/march/1/Bosch_Aquastar_240_FX_tankless_water_heater_18190.htm

http://www.complaints.com/directory/2006/june/14/26.htm

 4.   Will you be able to run more than one shower  at the same time.   Can it handle that or will you have to modify your life-style and take turns in the bath to accomidate the tankless unit??

Also,  on many brands  their is a water filter that needs changed out   "periodically".   Who pays for this?

5.   In   INDIANA   you  MUST  have a water softener to get  lime out of the water.  You MUST maintain very low hardness  level of your water.   Under 11 parts hard is best ...Indpls city water is presently rated at 20 - 26 parts hard.

 In My Honest Opinion....

This is NOT yet an  economically feasible product with   MANDATORY SERVICE  and  $$ breakdowns.   I doubt you will ever  recoup your original investment  .

I have   NEVER serviced,  or had to    "pamper like a little baby"    my 10 year old 50 gallon Rheem gas heater .

Keeping it simple simply works best ...

http://www.complaints.com/directory/2006/june/14/26.htm

http://www.handymanclub.com/DIY/Library/Products,_Tools_Tool_Use/Appliances/An_Endless_Hot_Shower.asp-------------------------------------------------------------------------------

Here are more   " hard numbers"  

Jan. 05  Bradford White   conducted extensive studies   Read this article,  it appears that the actual savings with a tankless heater  is less than nominal. .

 http://www.pmengineer.com/CDA/Archives/8cf9e86f7c298010VgnVCM100000f932a8c0____

    taken from the above article

The cold-water inlet temperature for testing was approximately 58¢  . The water was classified as hard with over 15 grains of hardness. The tankless water heaters were °de-limed  by circulating vinegar through the coil for one hour between the two-week tests. The efficiency declined somewhat as scale accumulated in the heat exchanger coil. All thermostats were set to provide an average outlet water temperature of 130ªF. The outlet water temperature of the storage water heaters varied more from the average tank setting, but the outlet water did not drop below 120ªF during most of the draws

( In Indiana our water can be  much  colder than 58 for at least  6 months out of the year and it is as hard as a rock...)

The operating cost savings for Tankless #2 over a M440T is $603.14 over 12 years, assuming a 4% inflation rate for energy costs. It also assumes that the water system has been softened or that Tankless #2  heat exchanger is periodically de-limed. This savings falls far short of a payback. The venting system material cost makes the economics unfavorable over a storage water heater for residential use. The service costs are an unknown factor for tankless products over this 12-year period. The Tankless #2 heat exchanger has a 10-year warranty, provided the water conditions meet the warranty requirements of fewer than 11 grains for hardness.

If any servicing is required, the repair cost is likely to be higher due to the complexity of the controls and higher skill levels required for diagnosing problems. 

 Read this first link for  " glowing testimonials" .

http://www.terrylove.com/forums/showthread.php?t=25461

  http://www.askthebuilder.com/451_Tankless_Water_Heaters.shtml

http://ths.gardenweb.com/forums/load/plumbing/msg0114073621251.html

Here are sites that do reviews on tankless units.    

http://www.consumersearch.com/www/house_and_home/water-heaters/reviews.html

the    BOSCH BRAND     has a very poor rating...

 http://www.epinions.com/Bosch_Natural_Gas_Tankless_Water_Heater_Aquastar_250SX/display_~reviews

http://www.epinions.com/Bosch_AquaStar_125B_NG_Natural_Gas_Tankless_Water_Heater/display_~reviews

For a tankless unit sized properly to meet your demands,   the prices will probably range  anywhere from $3000 to $6000.00 installed!

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