No hot water
If you have an electric water heater, there could be more than one reason why you don’t have hot water.
The power might have been turned off, or the power provider might be having
problems providing electricity and may be turning the power to your water heater
off at peak times (this is called ‘ripple control’).
If guests have been staying, they might have used more hot water than your
cylinder usually supplies.
You have an airlock in the pipes. See ‘A spurting, unpredictable hot tap’.
There may be a fault in the element (which heats the water), the thermostat (which controls the heat) or the tempering valve (which mixes cold water into the hot pipes outside of the cylinder before the water reaches the taps, to make sure it’s a safe temperature).
Check the power supply and wait for the cylinder to heat up again. If it doesn’t, you’ll have to call a plumber or electrician to check the element, thermostat and tempering valve.
If your heating is in-line gas heating, check that the gas supply is functional (empty bottle?) and that the power is on. If the power has been off for a period, the automatic shut-off will have come into play. Reset the temperature control and ON/OFF switch at the inside wall panel.