On Wed, 21 Oct 2015 03:39:49 -0700 (PDT), Cindy Hamilton
> wrote:

>On Tuesday, October 20, 2015 at 3:43:34 PM UTC-4, Dave Smith wrote:
>> On 2015-10-20 3:28 PM, Brooklyn1 wrote:
>>
>> > Firstly 140ºF is much too hot for domestic hot water, it'll scald you
>> > so you'd have to temper it with cold at the tap... what a waste of
>> > energy... 115ºF is plenty hot enough for bathing/laundry.
>>
>>
>> I figure I don't need my hot water to be any hotter than I can bear on
>> my skin. When I have a shower I can crank it up to full blast.
>
>Although it's very rare, legionella is a possibility in home hot
>water systems. I'd as soon keep my water heater high enough to
>kill it.
>
>The ideal range for legionella is 68 to 122 F; at 123-130 F legionella
>can survive but not multiply; at 132-140 F legionella is dead within
>30 minutes.
>
>I should time how long it takes to get hot water at the kitchen tap;
>it seems like an eternity considering how small my house it, but it
>can't be all that long.
>
>Cindy Hamilton

It also depends on ambient temperature, it can take twice as long here
in winter as water is much colder out of the pressurized well tank and
piping is colder... in summer hot water is out of the kitchen tap in
about 45 seconds, can double that in winter when temps are about zero
or lower. On average hot water out of the tap here is about a minute,
but can be half that if the hot water was used like an hour ago. I
try to do as much with hot water all at the same time, especially
since I mostly wash dishes by hand so I save the few dishes to wash
them all at once... but still the tankless on demand water heater is a
huge money saver... people with electric hot water taks don't realize
how often it comes on and how long it runs because it's silent, but
when I used a gas fired tank I sure knew how much it ran, even when no
hot water was used... I'd hear that thing come on several times at
night and run a long time... all wasted energy/money. I'd say more
than half my water heating fuel was totally wasted... with my new
tankless on demand no fuel is wasted. Plus I have the hot water set
to my comfort level (115ºF) so I rarely need to temper with cold. I
figue by not having a tankless on demand water heater for the twelve
years I've been here I've wasted at least $12,000 by heating hot water
for nothing, yoose with familys are wasting a whole lot more, a family
of four is conservatively wasting $25,000 in ten years. Naturally for
yoose who rarely or don't bathe. . . .