HELOC ADU Loan Calculator
A Home Equity Line of Credit is the most common way homeowners with significant equity finance an ADU. Payments are typically interest-only during the draw period, then amortize during repayment. This calculator shows your monthly HELOC payment vs a cash-out refi and construction-perm loan on the same build cost.
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Loan amount: $160,000
HELOC
Variable rate, interest-only draw option
Flexible line of credit. Only pay interest on what you draw.
Home Equity Loan
Fixed rate, lump sum
Predictable monthly payment. Full amount funded at close.
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 National region runs about $1,800/mo. That covers roughly 140% 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
What is a HELOC ADU loan?
A HELOC is a financing product structured specifically around the cash-flow and appraisal profile of an ADU build. The calculator above shows how its monthly payment, rate, and term compare to a standard HELOC on the same build cost.
Who should use a HELOC for their ADU?
Borrowers pick a HELOC when its structure (draw schedule, rate lock, qualification basis, or post-construction appraisal) lines up with their project. Compare the payment side-by-side against a HELOC and cash-out refi to confirm it is actually the cheapest path.
What credit and equity do I need for a HELOC?
Most ADU-specific loan products require a 680+ FICO and leave 15–20% home equity after the draw. DSCR loans are the exception — they qualify against projected ADU rent instead of personal income but tend to price 1.0–1.5% higher than a conventional HELOC.
Can I combine a HELOC with a HELOC?
Sometimes. Stacking products is legal but requires explicit lender approval on both sides. Many homeowners instead use a HELOC for the first phase (plans, permits, site prep) and refinance into a single long-term product once the ADU is complete and appraised.
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Credible
Compare prequalified HELOC and home-equity rates from multiple lenders in minutes — checking rates won't affect your credit score.
RenoFi
Renovation loans that qualify against your home's post-construction (after-renovation) value — built for new ADUs where you don't yet have the equity.
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