Phoenix ADU Loan Calculator
Phoenix opened up ADU permitting citywide in 2023 and build costs remain below most West Coast markets. This calculator compares HELOC, construction-perm, and cash-out refi payments against realistic Phoenix build costs.
Enter your project details
Loan amount: $152,000
HELOC
Variable rate, interest-only draw option
Flexible line of credit. Only pay interest on what you draw.
Construction-Perm
Draws during build, converts to mortgage
Funds disbursed by milestone. Permanent loan activates at completion.
Cash-Out Refi
Replaces your current mortgage
Combines existing mortgage + ADU cost into one new 30-year loan.
Rent-coverage estimate
Typical ADU rent in the Mountain region runs about $1,900/mo. That covers roughly 155% of the featured HELOC monthly payment shown above.
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ADU loan product comparison
| Product | Typical rate | Term | Best for |
|---|---|---|---|
| HELOC | 7.5–10.5% variable | 10 draw + 20 repay | Homeowners with 20%+ equity who want flexibility |
| Home Equity Loan | 7.3–10.3% fixed | 10–30 yr | Borrowers who want a fixed monthly payment |
| Cash-Out Refi | 7.5–8.5% fixed | 30 yr | Current mortgage rate already near market |
| Construction-Perm | 8.0–12.0% | 12–18 mo then 30 yr | Ground-up builds over $200K |
| DSCR | 8.5–12.0% | 30 yr | Investors qualifying on rent |
| RenoFi | 8.0–11.0% | 10–20 yr | Limited current equity, new-build ADUs |
Frequently asked questions
How do I get an ADU loan in Phoenix?
Start by pulling a recent appraisal to confirm your usable equity. Then get quotes from 2–3 lenders — local credit unions often beat national banks on HELOC rates, while a national construction lender may be the only option for a ground-up build. Use the calculator above to compare a HELOC, cash-out refi, and construction-perm payment on the same build cost.
What does an ADU cost in Phoenix?
Phoenix ADU builds typically run $130,000–$280,000 all-in. Detached units with full kitchens and utility hookups fall in the upper half of that range, while garage conversions and attached units come in lower.
Will Phoenix ADU rent cover the loan payment?
Detached ADUs in Phoenix typically rent for $1,500–$1,900 per month. Against a $200,000 HELOC at current rates, that rent covers 80–110% of the monthly payment in most configurations — meaning the unit usually cash-flows or comes close.
What ADU lenders serve Phoenix?
National lenders (Figure, RenoFi, LightStream) lend in every state. Local Arizona credit unions and community banks often offer the lowest HELOC rates for Phoenix homeowners. The lender-match CTA on this page connects you with three Arizona lenders that specialize in ADU financing.
Rebuild your cost estimate with different inputs.
Project long-term return on your ADU investment.
Complete guide to every ADU loan product.
Managing a Construction Loan? Stay on Top of Every Draw.
TerraLine gives you a real-time view of your loan balance, disbursements, committed costs, and remaining budget — so draw day never surprises you.