I'm with Ricarbo. Turning to the question originally asked:
"tonight i had to turn the temp up to 10 to get a decent temp"
so, a cold November evening... the water may be 5 to 10 degrees colder than it was in Summer, so you'll need more power to heat it to the same temperature.
Also your bathroom might be chillier, so you'll feel the cold more.
"is the unit on its way out"
I don't think you've found a fault in your shower.
im used to nice power showers
sadly, an instant electric shower isn't going to give a large flow of very hot water, like a stored water heater which has plenty of time to heat up a cylinder of water which gushs out in 10 minutes.
"tonight i had to turn the temp up to 10 to get a decent temp"
so, a cold November evening... the water may be 5 to 10 degrees colder than it was in Summer, so you'll need more power to heat it to the same temperature.
Also your bathroom might be chillier, so you'll feel the cold more.
"is the unit on its way out"
I don't think you've found a fault in your shower.
im used to nice power showers
sadly, an instant electric shower isn't going to give a large flow of very hot water, like a stored water heater which has plenty of time to heat up a cylinder of water which gushs out in 10 minutes.