On 10/5/2015 10:16 PM, micky wrote:

When I'm in the bathtub for even 30 minutes, either the water cools off
or it just feels like it has because I've gotten used to it. I have to
keep adding a trickle of hot water.

I was going to measure the temperature to see if it's what changes but I
haven't yet.

Probably some of both. Large surface area to give up heat, plus the tub
itself is a big heat sink, but you do get used to the temperature.