Quick Answer
Electric tankless water heaters are often a better choice than propane for off-grid systems, especially in well-insulated homes with a reliable solar or wind power source.
Off-Grid Suitability
Electric tankless water heaters require very little maintenance, no venting, and are free from propane safety concerns. However, they do require a significant upfront investment and often need a larger capacity to meet peak demand. A well-insulated home with a reliable off-grid power source can make an electric tankless water heater a cost-effective option.
Electric vs. Propane Sizing
To size an electric tankless water heater, consider the GPM (gallons per minute) requirement. A typical household requires around 2-4 GPM, but this can range from 1-6 GPM depending on the number of users and fixtures. For off-grid systems, it’s essential to choose an electric tankless water heater with a high enough GPM rating to meet peak demand and a sufficient kW rating to handle the electrical load. For example, a 240V, 4000W electric tankless water heater can provide 4 GPM, while a 480V, 6000W unit can provide 6 GPM.
Freeze Protection and Demand
Since electric tankless water heaters do not have a storage tank, they require additional freeze protection measures. This can be achieved through a freeze-resistant PEX piping system or a self-regulating heat tape wrapped around the pipes. To optimize demand, consider installing a high-efficiency showerhead and a low-flow faucet to reduce water usage. Additionally, a timer or occupancy sensor can be used to control the water heater’s operation and reduce energy consumption when not in use.
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