Updated August 15, 2026 · WattCostLab Calculator
Insulation Savings Calculator
Estimate potential annual savings from insulation or air-sealing improvements using your current heating and cooling energy use.
Use HVAC energy, not whole-home electricity when possible
Insulation primarily affects heating and cooling loads. If you use whole-home electricity, savings can be overstated because appliances, lighting and electronics may be largely unaffected.
Formula
Annual HVAC energy saved = baseline HVAC kWh × expected reduction. Annual dollar savings = saved kWh × energy price. Simple payback = project cost ÷ annual savings.
How to choose a realistic percentage
Use an energy audit, contractor analysis or calibrated building model whenever possible. Savings depend on existing insulation level, climate, air leakage, duct location, thermostat settings and heating/cooling equipment.
Related guides
See Attic Insulation Installation Cost, Spray Foam Insulation Cost and Home Energy Audit Cost.