This guide explains how the WeZero Smart Energy & Carbon Saving Tool works. The tool asks about your buildings, heating, lighting, equipment and vehicles, then identifies the efficiency measures most likely to reduce energy use, carbon emissions and cost. Each opportunity includes an estimated annual saving and payback period based on typical UK figures, helping you prioritise the measures with the fastest return. The guide covers the questions asked, how the estimates are calculated and how to use the results alongside your measured emissions in WeZero. The tool itself is free to use without an account.