Replies

1. 
   BillHartmann | Aug 22, 2008 12:03am | #1

   41,000 btu's.

   Unless this is just for washing hands and you are in FL I doubt that is enough.

   the manufactures will have charts showing temp rise with flow.

   and what kind of electrical loads do you have? sq ft of house, electric stove? dryer? ac?

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   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
1. 
   housenut1 | Aug 24, 2008 10:52pm | #4

   Hello Bill:

   Later I realized those numbers were for an electric model.  If we go the tankless route, it will be a gas model.  For my 1200 s.f. with two full baths and one teen, it looks like a 140000 BTU model is needed.

   Thanks

   Mike

1. 
   brucet9 | Aug 25, 2008 09:59am | #7

   "For my 1200 s.f. with two full baths and one teen, it looks like a 140000 BTU model is needed."Don't forget to check whether your gas line is big enough. Most residential gas water heaters are piped with 1/2". If yours is 1/2" your water heater would have to be within 15' of the meter with no elbows or tees to get enough gas volume to run your 140,000BTU heater. If it is 3/4", the meter could be 40' away.http://www.metrokc.gov/health/plumbing/gaspiping.htmBruceT

   Edited 8/25/2008 3:03 am by brucet9

1. 
   housenut1 | Aug 27, 2008 07:08pm | #13

   Thanks for the tips. I will keep it in mind when we do the water heater.

   Mike

2. 
   DanH | Aug 22, 2008 01:05am | #2

   Electric tankless rarely makes sense. Even gas-fired tankless is iffy -- some people swear by them but others swear at them, and there's little evidence of energy savings, etc.

   Too much sanity may be madness. And maddest of all, to see life as it is and not as it should be! --Miguel de Cervantes
1. 
   housenut1 | Aug 24, 2008 10:47pm | #3

   Thanks Dan H, I realized later that the numbers were for an electric one.  I think we will stay with a tank model.

   Mike

2. 
   Nuke | Aug 25, 2008 03:09pm | #8

   I'm betting the savings isn't in the direct energy consumption of tanked vs tankless, but I bet if I place point of use tankless systems in the kitchen and master bath I could something on water.

   I bet I lose a gallon of water each time I turn a faucet or shower on. Imagine ten times a day for about 3500 gallons. Ok, so maybe not even that is much of a cost savings, but how about my time and impatience. :)

1. 
   DanH | Aug 25, 2008 03:43pm | #9

   There are other (cheaper, simpler) ways to address that problem.
   Too much sanity may be madness. And maddest of all, to see life as it is and not as it should be! --Miguel de Cervantes

2. 
   brucet9 | Aug 27, 2008 09:32pm | #16

   "I bet I lose a gallon of water each time I turn a faucet or shower on."You're probably right. 24.5 ft of 1/2" pipe contains 1 gal water.BruceT

3. 
   TJK | Aug 24, 2008 10:55pm | #5

   At 120K BTU input you get 4 gal/min of hot water from a gas tankless. Electric is more efficient but I'd say 80K BTU (24 kW) is the minimum for a normal house. If you have 240V/100A service 24 kW pretty much maxes it out.

1. 
   housenut1 | Aug 27, 2008 07:17pm | #15

   Thanks for the advice.

   Mike

4. 
   Pelipeth | Aug 25, 2008 02:21am | #6

   I too had always been told, by everyone in "The Know" the only time you go tankless is with LP or natural gas. Elec. will end up costing you money.

1. 
   BillHartmann | Aug 25, 2008 03:50pm | #10

   "I too had always been told, by everyone in "The Know" the only time you go tankless is with LP or natural gas. Elec. will end up costing you money."People REALY IN THE KNOW know that the only way compare electric to gas is based on THAT PERSONS SPECIFIC RATES.With one exception if electric is more expensive than gas for a tank type WH then is is more expensive than gas for a tankless.And if electricity is cheaper than gas for a tank style tank it will be cheaper for a tankless.The one exception is that in some areas late night hours have some special very cheap rates. To use those one would need larger (depending on the number and pattern of use of HW)electric storage tanks and a time clock..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   DanH | Aug 25, 2008 04:00pm | #11

   But it's generally true that the "infrastructure" upgrade cost for retrofitting a gas tankless is significantly less than for an electric tankless. Gas unit may (or may not) require larger pipe and/or meter, electric unit will usually require a new electric service.
   Too much sanity may be madness. And maddest of all, to see life as it is and not as it should be! --Miguel de Cervantes

1. 
   BillHartmann | Aug 25, 2008 04:06pm | #12

   Either can be rather expensive to install. Can require lots of expensive SS vent pipe. And gas pipes replacement can be a lot hard to snake than electric..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

   Edited 8/25/2008 9:07 am by BillHartmann

2. 
   housenut1 | Aug 27, 2008 07:11pm | #14

   Thanks for the reassurance.

   Mike