opiesche,
Be careful when you select your HWT. All HWT have their minimum temperature unless it is a condensing one. If you just get regular DHWT and try to run it @ 80F you will end up with condensation problem.
For this reason if you use regular DHWT (non condensing type) you have to keep it @ minimum allowed temperature an install mixing valve.
I used special mixing valve
I050C2R-2 - Taco I050C2R-2 - 1/2", 2 Way Outdoor Reset I-Series Mixing Valve w/ Sensor which works as thermostat as well. It is pricey but worth every penny. Check eBay for better deal but make sure you get exactly this model.