Can you pair a propane heater with a solar hot water system?

Design Considerations

When integrating a propane heater with a solar hot water system, it’s essential to design the system with a hybrid control strategy. This involves setting a temperature threshold to switch between solar heating and propane backup. For example, you might set the threshold at 100°F (38°C) to ensure the solar system prioritizes heating water during the day, and the propane system takes over at night or during periods of low solar irradiance.

System Configuration

To pair the propane heater with the solar hot water system, you’ll need to configure the system to handle both energy sources. This typically involves installing a mixing valve to blend the hot water from the solar collectors with the hot water from the propane heater. A good rule of thumb is to size the propane heater to provide 10-20% of the total hot water demand, assuming the solar system is generating the majority of the hot water. For instance, if the solar system can provide 80 gallons of hot water per day, the propane heater should be sized to provide 8-16 gallons per day.

Safety Precautions

When integrating a propane heater with a solar hot water system, safety becomes a top priority. It’s crucial to ensure that the propane system is properly ventilated to prevent carbon monoxide buildup. Additionally, the propane heater should be installed in a well-ventilated area, away from any living spaces or flammable materials. Finally, it’s essential to install a shutdown valve to isolate the propane system in case of an emergency. This valve should be accessible from the outside of the building to allow for quick shutdown in case of a leak or other issue.