Can Off-Grid Propane Tankless Water Heaters Provide Enough Hot Water for?

Sizing and Selection

When selecting an off-grid propane tankless water heater, it’s essential to size the unit correctly based on the family’s hot water needs. A general rule of thumb is to choose a unit with a minimum flow rate of 6 gallons per minute (gpm) for a small family of 2-3 people, and 8-10 gpm for a larger family. For example, the Rinnai RUC75i is a popular choice for off-grid applications, with a flow rate of 6.6 gpm and a maximum temperature rise of 77°F (25°C).

Venting and Installation

Proper venting and installation are critical for safe and efficient operation of an off-grid propane tankless water heater. The unit should be installed at least 12 inches away from any combustible materials, and the vent must be sized correctly to prevent backdrafting and ensure proper combustion. It’s also essential to ensure the propane tank is installed correctly and sized to meet the unit’s demand, with a minimum capacity of 20 gallons for a small family and 30-40 gallons for a larger family.

Freeze Protection and Demand

Off-grid propane tankless water heaters require freeze protection to prevent damage from cold temperatures. A common solution is to install a freeze-activated bypass valve that allows the unit to bypass the heat exchanger when temperatures drop below a certain point. To ensure reliable performance, it’s also essential to consider the unit’s demand and select a model with a high demand response time. For example, the Ecodan GWP 25-30 kW tankless water heater has a demand response time of just 7 seconds, making it well-suited for off-grid applications.