Plan insulation upgrades with clear yearly savings estimates. Adjust area, fuel rates, and efficiency settings. Download reports, compare scenarios, and decide with confidence now.
| Scenario | Area | R before | R after | HDD / CDD | Electricity price | Install cost | Annual savings |
|---|---|---|---|---|---|---|---|
| Typical upgrade | 120 m² | RSI 1.8 | RSI 3.6 | 1800 / 600 | 0.16 per kWh | 1400 | Varies by inputs |
| Colder climate | 150 m² | RSI 1.5 | RSI 3.5 | 3000 / 300 | 0.18 per kWh | 2200 | Higher heating-driven savings |
| Cooling-focused | 100 m² | RSI 1.2 | RSI 2.8 | 800 / 1400 | 0.20 per kWh | 1600 | Higher cooling-driven savings |
Use these rows as starting points, then replace values with your real site conditions and tariffs.
This model estimates conductive wall losses only; air leakage, solar gains, thermal bridges, and occupant behavior can change real results.
For multiple insulation options, change only the “New R-value” and “Installation cost” to compare scenarios consistently.
Heat moves through walls whenever indoor and outdoor temperatures differ. Because walls can represent a large share of the building envelope, modest improvements in thermal resistance can reduce both heating and cooling demand. This calculator estimates those reductions using your wall area, climate degree days, and existing and upgraded insulation levels.
The strongest drivers are wall area, the change in R-value, and local heating and cooling degree days. Energy prices and system performance translate reduced thermal load into financial savings. Use realistic furnace efficiency or heat pump COP, and keep cooling COP consistent with your equipment. Small input changes can noticeably shift payback. If you do not know degree days, start with a regional average and refine later with utility or meteorological data.
Annual savings reflect the difference between estimated energy cost before and after the upgrade. In colder regions, heating savings usually dominate; in hot regions, cooling savings can be substantial. If your heating fuel is billed in therms, cubic meters, or liters, the calculator converts the tariff into an equivalent price per kilowatt-hour of fuel energy for comparability.
Simple payback divides net project cost by first-year savings, which is easy to understand but ignores future price changes. NPV discounts future savings back to today while allowing energy prices to escalate. A positive NPV suggests the upgrade returns more value than the discount rate. ROI compares total nominal savings against net cost over the assumed lifespan.
The plot shows projected savings across the insulation lifespan using your escalation and discount rates. The annual savings bars help compare scenarios, while the cumulative present value line indicates when discounted savings recover the net upgrade cost. Use it to test alternate insulation levels, incentives, and tariffs, then export the report for documentation. For audits, capture the scenario assumptions so future comparisons remain consistent across seasons and occupancy changes too.
Enter the net exterior wall area that is insulated, excluding windows, doors, and large unconditioned sections. If you only know floor area, estimate wall area from perimeter and ceiling height, then subtract openings for better accuracy.
Many weather services and energy agencies publish degree day summaries by city or region. Use the same base temperature across years. If you cannot find local values, start with a nearby city, then update when better data is available.
R and RSI are two common insulation ratings. RSI is metric; US R is imperial. The calculator converts them internally so you can enter whichever unit your product label uses.
It estimates conductive heat transfer through walls from degree days and U-values, converts to thermal kWh, then divides by efficiency or COP. Costs are computed using your energy tariffs, and savings are the difference between before and after.
NPV discounts future savings back to today and subtracts the net project cost. If NPV is positive, the upgrade is expected to outperform the discount rate assumption. It helps compare insulation options with different costs and lifespans.
No. This is a planning estimate focused on wall conduction. Air leakage, thermal bridges, moisture issues, HVAC sizing, and occupant behavior can change real performance. Use it to screen options, then confirm with site-specific inspection or professional assessment.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.