Thermoshield Cellulose Insulation Attic Calculator ThermoShield Cellulose Insulation Attic Calculator Use this calculator to determine how many bags of ThermoShield Insulation you will need to insulate your attic for the optimal energy efficiency. Measurement Type: ImperialMetric R/RSI Value: * Select R / RSI valueR-12 / RSI-2.1R-20 / RSI-3.5R-28 / RSI-4.9R-32 / RSI-5.6R-35 / RSI-6.2R-36 / RSI-6.3R-40 / RSI-7.0R-50 / RSI-8.8R-55 / RSI-9.7R-60 / RSI-10.6 Attic Area: (sq. ft.) OR Length:(ft.) X Width:(ft.)