Turn retrofit data into clear annual cost forecasts. Model rebates, escalation, loans, and maintenance easily. Decide faster with savings, payback, and value metrics today.
Large screens show three input columns, smaller screens show two, and mobile shows one.
| Scenario | Baseline (kWh) | Post (kWh) | Cost ($) | Rebates ($) | Year‑1 Savings ($) | Simple Payback (yrs) |
|---|---|---|---|---|---|---|
| Insulation + LED | 10,500 | 7,600 | 4,200 | 600 | 330 | 10.91 |
| HVAC tune + controls | 14,000 | 10,300 | 5,300 | 800 | 470 | 9.57 |
| Windows retrofit | 12,800 | 10,900 | 8,000 | 1,000 | 260 | 26.92 |
| Heat pump upgrade | 18,500 | 12,200 | 9,600 | 1,500 | 940 | 8.62 |
| Whole-home package | 20,000 | 12,800 | 14,500 | 2,000 | 1,130 | 11.95 |
After calculation, the first five years appear here for a quick check.
Retrofits change consumption patterns; the first checkpoint is Year‑1 cost. The calculator multiplies baseline kWh by the baseline rate, then compares it with post‑retrofit kWh at the post rate plus maintenance. If baseline usage is 12,000 kWh at $0.14, the starting cost is $1,680. If post usage drops to 8,200 kWh with $120 maintenance, the new cost is about $1,268, producing roughly $412 of Year‑1 gross savings.
Projects rarely equal equipment price alone. Enter total retrofit cost and subtract rebates or incentives to estimate net upfront investment. Maintenance matters because it competes with energy savings every year, especially for systems with filters, monitoring, or service plans. Including incentives and upkeep helps avoid optimistic payback estimates and makes comparisons between upgrade bundles more realistic.
Utility prices and service costs usually rise over time. The escalation input grows baseline and post costs each year, so savings follow the same trend. The discount rate converts future net savings to today’s value for NPV. A 6.5% discount rate reduces the weight of year‑10 savings versus year‑1 savings, useful when comparing upgrades against alternative investments clearly.
If you finance the project, the calculator estimates an annual loan payment using an amortization formula. Those payments are subtracted from gross savings during the loan term to produce net savings. Financing can delay break‑even even when the upgrade is efficient, but it can also preserve cash for other priorities, so review both NPV and the break‑even year.
Use ROI to understand scale, NPV to understand value, and the break‑even year to understand timing. When NPV is positive and break‑even occurs within your planned ownership period, the retrofit is financially supportive overall. If break‑even is not reached, adjust assumptions: tighten maintenance, refine post usage, or model different incentives and escalation paths.
Post retrofit usage is the expected annual energy consumption after upgrades. Use utility bills, sub-meter data, or contractor estimates. The calculator converts that usage into cost and compares it against the baseline to estimate savings.
Use a rate that reflects your opportunity cost or required return. Many households use 3% to 8%. Higher rates reduce the present value of future savings, which can lower NPV and make long payback projects look less attractive.
Escalation increases energy and maintenance costs each year. If prices rise, the gap between baseline and post costs may widen, increasing savings. If you expect flat prices, set escalation to 0% for a conservative estimate.
Enter the total rebate value as incentives. If your rebate is contingent or delayed, model a smaller amount for conservative planning. For complex programs, run two scenarios—one with full incentives and one without.
When financing is enabled, annual loan payments are subtracted from gross savings during the loan term. This can delay break-even even if the retrofit reduces energy usage. Compare NPV with and without financing to see the trade-off.
It is an approximation based on your CO2 factor input. Grid emissions vary by region and time. If you have a local emissions factor from your utility or regulator, replace the default value for a better estimate.
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.