On Tue, 25 Sep 2018 07:57:06 -0500, Terry Coombs
wrote:

On 9/24/2018 11:33 PM, Clare Snyder wrote:
On Mon, 24 Sep 2018 13:00:25 -0500, Terry Coombs
wrote:

On 9/24/2018 12:23 PM, Clare Snyder wrote:
On Mon, 24 Sep 2018 17:08:19 +0100, Roger Johnson
wrote:

A friend who was contemplating replacing his always on gas fired 50 gallon
hot water heater setup with an on demand system told me there's no
economics in it after he ran a long term test (for months).

He gauged his propane use by his monthly fillup gallonage during the summer
months where the outside temperature was relatively steady and warm (so the
tank fills were all to about 80 percent).

He didn't see ANY difference in propane use between these two scenarios.
Control: 50 gallon hot water heater left always on
Testing: He turns on the hot water heater each morning for an hour

Since it's just him, his wife, and one other adult, they can all take
showers in the morning on that schedule.

Given that a new on demand system could cost as much as five grand,
would you agree with him that on-demand systems have no economic value?
Been saying that for years - they will never last long enough to pay
foe themselves
* What's your take on point of use heaters ? Ours is a small one , only
about 1.5 gallons , mounted in the crawl space under the kitchen sink
area . The reason we got it was because hot water took too long to get
from the main heater (40 gal electric) to the dishwasher/sink .
Additionally , the main is set at 130° or so and we wanted minimum 140°
at the dishwasher . Never got over 120° coming from the main to the D/W
and that ain't hot enough to sanitize the dishes .

Excellent solution. Point of use on demands work good for some things
too (they hold a quart or so of steeming hot water and draw about 1500
watts - like an "on demand tea kettle"

* Did you miss the part where I said "ours is a small one , only about
1.5 gallons" ?
Nope - didn't miss it. That's "medium sized" for a POU. 5 is
typically the largest.