If cost per btu of both fuels is the same, or nearly, this is not
true. Electric is near 99% efficent, your average gas tank sold is
near 50-65% efficent, with the high end on condensing Ng around 80-85%
total efficency, known and rated as EF. Recovery or performance is
what you buy and need. Gas also loose efficency every year due to
scale buildup that does not affect electric units. And how many ever
have their burner checked to be sure its burning right. A premium
could be paid for electricty and an electric could still be cheaper to
run. Every areas fuel and electric costs are different so run your own
What is the point of your statement, I guess you dont realise it is
still transfering heat and has nothing in similarity with scale at the
bottom of the tank. The electric element is submerged in water, In Ng
the heat is outside the tank transfering through metal and scale, the
less that transfers the more of your money goes up the chimney. Scale
in the tank bottom impeedes heat transfer. Why not google scale -
reduced efficency and learn why Ng tanks loose efficency every year. I
pulled out a 15 yr old Ng tank that had 12" of hard scale in it, my
new water heater cut my bill alot.
Scale buildup effects gas heaters differently then it does electric. Scale
slows down the heat transfer into the water. The hot gas goes by and if it
doesn't transfer right then and there into the water, the hot gas is
exhausted and the heat energy is vented into the atmosphere. A little bit of
scale can make a big difference, and efficiency goes out the window.
With electric heaters, scale buildup on the element slows down the heat
transfer from the element into the water. The element gets hotter which
increases it's resistance, and less current flows. However, almost all of
the heat still makes it into the water - where else is it going to go? Even
with old scale coated elements, most of the heat goes into the water and
efficiency remains very high. You don't waste electricity, you don't loose
efficiency, you just don't get your water heated as fast.
The scale on an electric heater does not reduce efficiency. 100 BTU
in water gets 100 BTU In a gas you put 100 BTU (after taking all
factors other than scale into account) in you will get less as the
scale builds up.
That said, in almost all areas the cost of heating water is cheaper
with gas than electric even after accounting for scale.
But. . . A scale covered electrode will transfer those BTUs to the
water slower than a clean one. [can one of you ashrae engineers check
the emmisivity index of copper vs limestone] To compensate for this
slower transfer the homeowner will raise the temp of the tank-
increasing losses- and making the electric less efficient.
On tank life- get the one with the longest warrantee. Pray. Get lucky.
[my cheap LP heater just croaked this week. It was approaching 20
Nonsense. If you have a 4500 Watt element submerged in water, where
do you think the heat is going while it's waiting to get to the
water? If the heat isn't going directly to the water, it would have
to be stored somewhere else. And where would that be? Sure, a
scale covered element will run slightly hotter, but it's not going to
be at all noticeable to the user in terms of how hot the water
gets. If it's severly covered or totally buried, it will eventually
:> Hi,:> Under same condition, only comparing tank life, which one would last:> longer, natural gas one or electric one?
: electrics tend to last longer.
Don't about you, but my ng water heater just turned 18 this year.
But what about the burner? The products from gas combustion are slightly
corrosive and self-destructive over time, yet I'm sure they do last quite a
I would think a properly designed electric unit might outlast the gas unit.
modern tankless with no pilot light, have complex flame sensors
igniters, and monitors.
once a part fails, if its no longer available you are stuck, plus the
heat exchangers can clog from sediment.
do not assume a tankless is forever, after all how many newer products
Modern condensing tanks have more complex parts, so does much other
heating and cooling equipment, my AO smith has 2 fans, 3 vacume
valves, and large circute board, am I worried I wont be able to repair
my 2000$ water heater tank, no. These companies will maintain
replacement parts just as your furnace, Boiler or AC unit. Hallerb you
always do whatever you can to put down Tankless, since you dont have
one, go buy one and save up to 30 % in gas off your new unefficent
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