Most Repairmen will charge a $50 service fee and usually around $75 an hour plus the cost of parts. If you need to replace your water heater that will cost between $700-$100 depending on size and brand.
they get paid u mom
A tankless water heater uses less electricity compared to a traditional water heater because it only heats water when needed, whereas a traditional water heater continuously heats and stores water.
A tankless water heater is much more efficient as it "flash" heats the water.
The installation of a solar water heater will cost between $250-500.
None.
You constantly need hot water
It depends on what is broken on your water heater, as to how much it would cost to fix it. It might actually need to be replaced and be more cost effective to replace it.
Depends how much plumbers charge in Seattle. -It takes about 3 hours to install a gas tank if it's a straightforward installation and no other pipes or obstacles are in the way. (I do many)
Not much, it gets warm as everything else within the heater's range.
Aside from heating water, pretty much nothing.
a direct vent water heater is more fuel efficient (cost's less to operate). aside from that there isn't much difference, aside from not needing a double wall flue through the roof on a standard gas water heater.
"How much" as a question is quite vague. Some hot water heaters are comprised of copper only. So this now depends on the size of the hot water heater. Some hot water heaters have no copper whatsoever.