QUESTIONS
a. Is there some small parasitic draw on the battery, and/or some wear and tear on the system/Is there any cost to running these systems while not being used?
b. What if we left the water pump on while going in motion, would the pressures of movement cause stress damage to the system?
ANALYSIS
1. Keeping the water heater powered on overnight consumes electricity. A very small amount of electricity, but electricity, nonetheless.
2. Keeping the water heater on overnight is unlikely to shorten the lifespan of the unit by any measurable amount.
3. Keeping the water pump on overnight will cause it to cycle on occasionally as the system loses pressure. This will consume a very small amount of electricity.
4. Keeping the water pump on overnight will also consume some of the unit's total lifespan. If this impact could be measured is debatable.
5. Keeping the water pump on while driving will have no negative impact.
6. Battery use due to having the water heater and water pump powered on overnight will consume some of the batteries' total lifespan. If this impact could be measured is debatable.
DISCUSSION
1. I am a compulsive switch turner-offer. Left to my own devices, everything would be off when not in use overnight. No question about it. This is not because doing so would produce a measurable impact. It won't. This is strictly an emotional choice.
CONCLUSIONS
1. The net cost in electricity, and the net cost in shortened device life due to leaving the water heater and water pump on overnight is so minimal that it is indiscernible.
2. Turning things off makes some people happy. This is totally discernible.
3. Leaving things on makes other people happy. This is also completely discernible.
4. In your case, I shall hypothesize that if you leave this set of devices powered on overnight, the net cost to you in loss of happiness will be far outweighed by the net gain to you in joy due to an ecstatically happy face-washer in the morning. You know, you might even get coffee in bed outta the deal. I say: leave the switches on, and enjoy the heck out of watching the happy face-washer dance every morning. That's what we call a high return on investment.