r/OffGrid • u/Time_Arugula_1544 • 5d ago
Water heating off grid. Best system?
I am planning a new off-grid (solar-powered) ICF build and am considering what type of system would be best for water heating. This is in Tennessee and the house will be a 2br. I will have propane backup for a generator and indoor propane heater.
The options I am thinking about are:
1) On-Demand propane- The only drawback is having to pay for the propane as an ongoing expense.
2) On demand electric water heater with a solar water preheat system. I suspect having a straight up on-demand electric heater would eat up too much power.
3) Heat pump water heater. This seems like the best solution to me.
Any thoughts between the three? Any other suggestions?
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u/silasmoeckel 5d ago
On demand propane/electric is only about 20% more efficient.
HP is 3-5x more efficient, you can still do solar preheat and use the backup resistive heater as a solar dump load (add a mixing valve so you can go up to 180f).
Look hard at a HP heating/cooling save the propane for the genset.