Water heater slow to rewarm water

[jfowler218]

I usually shower first in the morning and my wife follows an hour or so later. She complains there is only luke warm water available. We have tried using both gas and electric to heat the water. There is always hot water available from the sink when she showers.
How long should it take the heater to reheat water? Is it possible the shower faucet is at fault?

[HowieE]

If you have hot water at the sink for the second shower it is not a heater problem but rather the mixing valve limit on the shower is set too low to allow enough hot water to the shower head.

Newer shower valves have adjustments built in them to insure you can't scald yourself.

Remove the valve assembly and you should find a ring with teeth around the outside of the ring. Each tooth generally equals 3 degrees of temperature change.