Solar + Battery figures sourced directly from OpenSolar report. Sentinel uplift figures are estimates based on system size, battery capacity, usage pattern, tariff type, and Joulen residential scenario benchmarks (March 2026). Trading revenues are not guaranteed. Sentinel market revenues shown net of 20% Joulen trading fee. Peak shaving and market trading revenue are not fully additive as they share the same battery cycles; a 15% non-additivity adjustment is applied to their combined total. Sentinel bill savings are capped at 95% of total estimated electricity spend (annual consumption × effective import rate) to prevent overstating savings relative to actual usage. Sentinel subscription cost (£199/yr) deducted from year 2 onwards in Sentinel cumulative figures. Rate of return with Sentinel is calculated from 25-year cumulative return relative to system cost. Energy price inflation applied at 7% per annum to cumulative projections. This calculator is a sales support tool for HSEnergy surveyors and should not be presented to customers as a guaranteed financial forecast.