Can I Use a Batch Heater for Radiant Floor Heating?

Choosing the Right Batch Heater

A batch heater, also known as a wood-fired water heater, is a good option for radiant floor heating if it can supply a consistent and reliable heat source. Look for a batch heater with a high-output rating, typically around 20-40 kW, depending on the size of your space. For example, a 20 kW batch heater can heat 1,000-1,500 square feet of living space, assuming 10-15 BTUs per square foot.

Designing a Thermosiphon System

To use a batch heater for radiant floor heating, you’ll need to design a thermosiphon system to circulate the heated water. This involves installing a large tank, typically 100-200 gallons, to store the heated water. The tank should be elevated above the stove coils to allow gravity to circulate the water. The system should also include a well-insulated piping network to minimize heat loss. As a general rule, the piping should be sized to maintain a minimum flow rate of 5-10 gallons per minute.

Installing Stove Coils and Radiant Floor Panels

Once the thermosiphon system is designed and installed, you can attach the stove coils to the batch heater and install radiant floor panels in the desired areas. The stove coils should be sized to match the output of the batch heater, typically 1/4 to 1/2 inch in diameter. The radiant floor panels should be made of a durable material, such as PEX or copper, and should be spaced approximately 12-18 inches apart. The panels should be installed in a serpentine pattern to ensure even heat distribution.