Hybrid Car – More Fun with Less Gas

tankless water heater - Page 3

register ::  Login Password  :: Lost Password?
Posted by Josepi on November 29, 2010, 7:18 pm
Damn teranews server doing again!

My apologies for the multiple postings.

If you are using electric water heating, now I wouldn't bother. There is not
really any gain in economy.

Your lights may dim and you could overload your electric service, depending
on how modern your wiring / fuse panel is.

I doubt you will have enough hot water supply to supply a shower and a dish
washer at the same time.
My rinnai gas unit runs 185,000 BTU and it can be "just barely enough"

Learn the BTU math and get educated so they can't sell you the "infinite
supply of hot water" BS. If your water comes form the ground at 45F your BTU
cannot produce as much volume due to a limited BTU rating. Do the math.

There is also (in a gas unit moreso) a delay in reecognizing water demand so
if you trun the tap on and off repeatedly you may never get hot water. This
inputs a cold water shot ("sandwich") in your pipes if you did this in the

home depot and lowes sells these, models requiring either 2 x 40 amp or 3 x
40 amp
breakers, depending on power

has anyone installed these and what are your observations / recommendations

Posted by m II on December 1, 2010, 1:36 am
On 10-11-29 05:34 AM, todd wrote:

Don't do it. A neighbour converted from electric water heat to a normal
gas fired tank. Her monthly electric bill went down by over three
hundred dollars...and that is at 8.3 cents for a kilowatt hour.

Hers was the 2 X 30A version of an 'instant' on water heater setup.


Posted by daestrom on December 2, 2010, 10:57 pm
 On 11/30/2010 8:36 PM, m II wrote:

She must have had a short circuit or something wrong with the unit.

$00 at 8.3 cents would be about 3600 kWh.  That's on the order of 12
million BTU, enough to heat almost 15000 gallons of water from 40 degf
to 140 degf.

If she really uses that much hot-water in a month, that's one
loooonnnnggg shower :-)


Posted by m II on December 5, 2010, 4:42 am
 On 10-12-02 03:57 PM, daestrom wrote:

I messed up that posting. There were two heater elements installed in
the copper hot water line. Each was 240 volt 30 amps, So there were two
2 pole 30 amp breakers.

No storage tank at all. A thermostat, via a relay, would kick in the
elements. They were threaded into 1 inch 'T' fittings. This was nothing
like the newer Bosch or similar tankless units.

What she saved in installation costs was made up for very quickly by
energy usage. I don't remember if they had in floor heating or a hot tub
on top of the normal hot water demands.


Posted by ransley on December 5, 2010, 1:13 pm
30 dollars ok, 300 no way unless she had a major short.

This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread