Fuel Price Indices (FPI) calculator: An Excel-based tool for inclusion of the social cost of carbon (SCC) in energy audit in weatherization assistance program. It aligns with the guidelines outlined in WPN 22-10 and leverages fuel cost modifiers, considering year and fuel type. Its outputs, including modified fuel prices and FPI, can be used with Weatherization Assistant versions 8.9 and 10.05, facilitating comprehensive energy analysis and decision-making.”