Is a Backup Water Heater Necessary with Wood Systems?

System Design Considerations

A well-designed wood-based hot water system typically includes a large storage tank, often 80-120 gallons in size, and a high-capacity heat exchanger, such as a 3-4 square foot plate heat exchanger. This setup allows for adequate storage and efficient heat transfer, reducing the need for a backup water heater. Proper system design also involves considering system losses, such as heat loss through pipes and system inefficiencies, to ensure the system can meet peak hot water demands.

System Redundancy and Backup Considerations

System redundancy and backup considerations become more critical in cold climates or high-demand households. In these cases, a backup water heater, such as a 50-gallon electric water heater, can be installed to supplement the wood-based system during periods of low wood energy availability or high hot water demand. This setup requires careful system design and monitoring to ensure efficient operation and minimize backup water heater usage. A well-designed system with a backup water heater can provide reliable hot water even during extended periods of low wood energy availability.

Real-World Example

A 3-bedroom home in a cold climate with a wood-based hot water system might require a 90-gallon storage tank and a 4-square foot plate heat exchanger. In this scenario, a 50-gallon electric water heater can be installed as a backup to supplement the wood-based system during periods of low wood energy availability or high hot water demand. Proper system design and monitoring are crucial to ensure efficient operation and minimize backup water heater usage.