The Resale Trap Tools
Free Tools for Build-vs-Buy & 25-Year Cost Math
Ten tools that put the book's 25-year model on your specific deal: lifecycle cost simulator, state-by-state energy code ROI, uninsurability risk scoring, deferred maintenance forecasts, disaster-zone premium adjustment, inspection defect classifier, builder incentive stack math, and more.
Important: These tools produce informational estimates and AI prompt templates. They are not real estate, legal, tax, insurance, construction, appraisal, or financial advice. Costs, codes, incentives, and disaster risk vary widely by local jurisdiction and individual property. Do not buy, sell, or refinance based on these numbers alone. Engage a licensed real estate agent, home inspector, structural engineer, insurance agent, and lender before any transaction. See full disclaimer →
Core Calculators
Full-page calculators (sorted A–Z)
Commission Savings Calculator
Flat-fee MLS + title company + attorney vs traditional 5–6% commission. State-aware (Colorado, attorney-required states).
Cost of Homeownership Calculator
25-year total cost for a new build vs a resale — mortgage, tax, insurance, maintenance, capex, PMI, and opportunity cost.
FIRE Calculator
Financial Independence / Retire Early math — how the build-vs-buy decision moves your FI date.
Opportunity Cost Calculator
What your down payment would have earned invested instead — the hidden cost most buyers never model.
Inline Mini-Tools & AI Prompts
Build-New vs. Buy-Used 25-Yr Simulator
Location + square footage + build year + energy code → lifecycle cost comparison: purchase, energy, insurance, capex, and resale equity.
State-by-State Energy Code ROI
Which code does your state enforce? 2021 IECC and 2024 IECC adoption drives energy bill delta between new and old homes. Ranked by annual savings.
Uninsurability Risk Score
Identify which legacy systems are insurer-killers: knob-and-tube, Zinsco/FPE panels, polybutylene, aluminum wiring, > 20-yr roof, 4-point inspection failures.
Deferred Maintenance Capex Forecast
Age × system (roof, HVAC, plumbing, elec, windows, water heater) → $/yr capex forecast over 10 years.
Disaster-Zone Premium Adjuster
FEMA flood zone + wildfire WUI + hail corridor + wind zone → annual insurance premium delta versus median home cost.
Inspection Defect Classifier
Paste an inspection report summary. AI prompt returns critical / major / minor defect classification with estimated repair cost bands and negotiation leverage.
Resale Trap Ch 19: Inspection Triage
Builder Incentive Stack Calculator
Rate buydown + closing credit + upgrade package + title forgiveness → true APR, 5-yr NPV, and effective discount off list.
Appraisal Gap Predictor
New construction vs. resale comps — if builder price is $475K and recent used sales are $335K, expect an appraisal challenge. Estimates gap risk and how to handle.
Smart Home & IoT Readiness Score
EV-ready, heat-pump-ready, solar-ready, battery-ready, gigabit-ready. Future-proofing score for resale to 2030+ buyers.
Builder Warranty Value Analyzer
Monetize the 1/2/10 warranty most builders offer — and compare to the reserve you'd need as a used-home buyer.
Pair with the book's core calculators (A–Z): Commission Savings Calculator, Cost of Homeownership Calculator, FIRE Calculator, Opportunity Cost Calculator. Full site analyzer suite at jwatte.com/tools.