Estimate the key quantities and planning outcome for a attic conversion project using inputs you can adjust to match the property and proposed scope. The calculator separates the main result from supporting figures, making it easier to check contractor assumptions, compare options, and identify which input has the greatest effect. Results are planning estimates rather than a substitute for field measurements, product specifications, written bids, or local permit guidance.
This is simple payback; it does not discount future cash flows.
The main result summarizes the entered project scope, while the secondary figures expose the components behind it. Treat the estimate as a consistent comparison baseline and investigate any large difference between this result and a contractor proposal.
Actual requirements can change with field measurements, structural conditions, code, product instructions, disposal rules, taxes, labor practices, and the final contract scope.
A $75,000 conversion adding $55,000 in value leaves $20,000 unrecovered. A $900 monthly benefit less $1,800 annual costs equals $9,000 per year, for a 2.2-year simple payback.
No. It is a simple payback estimate and does not include loan interest, inflation, taxes, or discounted cash flow.
The calculator reports no payback because the entered recurring benefit cannot recover the remaining cost.
Enter confirmed rebates or incentives where provided so the calculator can reduce the upfront amount.
It is an estimate of value, not cash proceeds. Use it cautiously and obtain a local appraisal when the distinction matters.
Actual results depend on sale timing, utility rates, maintenance, occupancy, taxes, financing, and future costs.
| Component | Treatment |
|---|---|
| Value added | Offsets upfront project cost |
| Monthly benefit | Converted to an annual amount |
| Added costs | Deducted from recurring annual benefit |