Insulation for furnace flues should be:

Insulation for furnace flues is crucial for maintaining efficiency and safety in a heating system. The correct choice emphasizes using single-warp tight insulation. This method provides adequate thermal resistance, ensuring that the heat generated by the flue gases is retained, which minimizes the risk of heat loss and potential condensation.

The single-warp tight insulation is specifically designed to conform closely to the surface of the flue, preventing air gaps that could lead to heat loss or the emergence of hot spots. By providing a snug fit, it enhances the operational efficiency of the furnace and reduces the risk of dangerous overheating or fire hazards associated with improperly insulated flues.

This choice aligns with standard practices for insulating furnace flues, where the goal is to maintain a balance that allows for efficient operation while minimizing risks.