Did you see the date of a reply puts that pre-03. Back in 03 I would go with
because they were reletively new but today's units have a lot more going for
Research the latest, I did and we are using a propane tankless from Bosch.
It is 100 percent because the efficiency rating is
based on the conversion of the heat potential of
the fuel to the heat potential of the water. Loss
of heat because of poor insulation of the tank
etc. is not part of the "efficiency" rating. And
it has to be that way because no one can predict
or account for all the possible combinations of
installation including outside (no protection),
cold garage, small closet, etc. If efficiency did
include other factors, gas water heaters would
have a terrible efficiency (just think of that
hole through the center of tank and the air heated
by the hot water rising through the flue pipe to
> Electric? It makes no difference as electric is 100% efficient.
Nothing is 100% efficient.
Electric still may be a good choice, IF you do the following:
1) Must have an off peak heating rate to make it economically feasible.
2) Off peak heating means you need a large tank, at least 80-100
gallons for a family of 4.
Remember, you will be heating water at 2:00AM for a hot shower at
6:00PM that night.
My father built a house and followed the above guidelines.
We always had hot water during the 10 years I lived there, before
Who cares about "ratings"? The fact is that some water heaters
are better insulated, and will cost you less to operate. They
lesser insulated ones are less "efficient". 100%? I don't think so.
Sure, they convert 100% of the energy to heat in the water. But
then they lose the heat to the environment. IF you use a cheaper
source of heat to heat your house, or if you want to cool it, that
is going to cost you money.
It is 100% efficient in turning electricity into heat. It is not 100%
efficient in transferring that heat to the water nor is it 100% efficient in
turning fuel into heat. It just moves the point of inefficiency from a
local burner to a generating plant.
I don't know why folks quote that old saw: "electric is 100%
efficient". It's a meaningless statement.
Electric usage for resistance heating may well be 100% efficient at
the end user site but that doesn't take into account the large losses
at the power plant, the distribution system, house wiring losses,
These combined losses are among the reasons why electric resistance
heating of anything is generally more expensive than natural gas,
unless the electric source is hydro or subsidized.
Your argument ignores the fact that efficiency in
this context means the efficiency of conversion
from one type of energy to another, in this case
electricity to heat. Losses at the power plant
are the result of a different conversion,
converting coal or gas to electricity.
If you want to add up all the losses and cost you
have to include the cost of mining the metal in
the heater among about 10,000 other things.
You may want to check out:
Of course they're trying to sell their product, but it appears they offer
some decent advice. I too am thinking I'll be replacing soon so found this
here in buffalo ny: natural gas is cheaper fuel. we had 9 days no
electric after the freak october 13, 2006 22-inch wet snowstorm that
knocked 1/3 of a million people off the electrical power grid with
we had no interruption in hot water. [i once wished i bought the ebay
showerhead with a generator light in it.]
note here a 40,000 BTUH with standing pilot light gas water heater has
around a 61 gallon delivery in the first hour. note gas is usually
twice the recovery rate with gas at 40 gallons per hour and electric at
20 gallons per hour on the lower priced conventional household units.
and winter water to shower water temp is more than a 90 degree rise
requirement in this climate.
see various manufacturers websites but GRAINGER has excellent
comparison specifications information on their website:
also see extensive choosing and add-ons and troubleshooting of your
next water heater:
Jay Pique wrote:
I just built a new house 3 years ago and did the finish plumbing and
would like to comment on recirculation water. I had a 48' run from
the water heater to the shower on the other end of the house and
thought it would be wise to put a pump in a loop back to the water
heater. I also purchased a motion sensor switch that I put in the
bathroom to turn the pump on when the room was entered that also had a
manual switch on it so it could be turned off and the pump turned on
manually. These are available at Lowes. I insulated the supply and
return runs to the water heater. In the end I found the pump and my
switch set up were un-necessary since the water would re-circulate by
natural convection. I don't know what the situation would have been
if I would have wanted to do it to an upstairs floor. I would have had
to insulate the pipes going to upstairs walls before covering and so
on. My situation was water heater in basement and shower on the
opposite end of the house worked out fine.
ELECTRICITY is the MOST expensiv per BTU than any other heat source in
most of the country. primarlily because electricity is made frequently
by burning natural gas or other fuel sources, add a step in the process
effcency of tank is printed on energy guide label along with average
costs to operate for compatison purposes. foam insulation is very good
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