Finance · 8 min read · January 30, 2025 · 368 words
Financing an ADU without overpaying for the privilege
HELOC, cash-out refi, renovation loan, or cash: a side-by-side on the four real paths LA homeowners use — and the rate math that decides between them.
Key takeaways
- Cash — lowest cost, gives up liquidity.
- HELOC — fast, flexible, variable rate, refinance later.
- Cash-out refi — only attractive when current rates are favorable.
Answered in this guide
Jump straight to the question you came in with — every answer is on this page, with links onward to the deeper guide.
- What kind of return on investment can I expect?
- Are there grants or rebates available?
- What does an ADU cost in LA?
- What's included in your turnkey number?
- Will building an ADU raise my property taxes?
- Can I rent my ADU on Airbnb?
More across the studio · the full FAQ map · the reference desk
There is no single right way to finance an ADU. There are four real paths, and the right one for you depends on three numbers: your current mortgage rate, your available equity, and your tolerance for variable-rate debt. Model the monthly payment on the financing calculator before you call a lender.
1. Cash
If you have it sitting in a HYSA earning 4%, paying cash for an ADU that yields 9–11% gross rental return is a clean trade. The downside is opportunity cost — you give up that liquidity and can't easily put it back if you need it. The rental yield guide gives the realistic return assumptions.
2. HELOC (Home Equity Line of Credit)
Revolving credit secured by your home equity, typically interest-only during the draw period. Variable rate (currently around prime + 0–1.5%). Best when you're confident you'll refinance the construction debt into a permanent mortgage within 24 months.
3. Cash-out refinance
Refinance your primary mortgage for more than the balance and take the difference as cash. Best when current rates are at or below your existing mortgage rate. Worst when current rates are 2+ percentage points above — you'd be repricing your entire mortgage to fund $250K of new debt.
4. Renovation construction loan
Construction-to-permanent loan products (Fannie Mae HomeStyle, Freddie Mac CHOICERenovation) underwrite based on the post-build appraised value of the property. Best when you don't have enough current equity to cover the build with a HELOC. The HELOC vs renovation loan deep-dive compares all four products line by line.
Side-by-side, simplified
- Cash — lowest cost, gives up liquidity.
- HELOC — fast, flexible, variable rate, refinance later.
- Cash-out refi — only attractive when current rates are favorable.
- Renovation loan — best for low-equity homeowners or first-time builders.
Sources
- CalHFA ADU Grant Program · California Housing Finance Agency
- Fannie Mae HomeStyle Renovation · Fannie Mae
- FHA 203(k) Rehabilitation Mortgage · U.S. Department of Housing and Urban Development
- Consumer Financial Protection Bureau — HELOC basics · CFPB
Next chapter · 01 of 03
Finance · 9 min read
HELOC, cash-out, renovation loan: the ADU money decision
A product-by-product breakdown of the four loan options — including the one most homeowners don't know exists.
A practical comparison of the four ways LA homeowners actually pay for an ADU — including the one product (renovation loan) that lets you borrow against the finished value.
FAQ · Finance
Common questions on finance
The questions readers send us most after this guide.
What kind of return on investment can I expect?
Across the LA projects we deliver, owners see 10–16% annual return on construction cost in long-term rental. The math: a $280K detached ADU renting at $2,800/month grosses $33,600/year — roughly a 12% gross yield before expenses. Property value uplift is typically 1.4–1.7× the build cost on appraisal.Are there grants or rebates available?
The CalHFA ADU Grant Program ($40K toward soft costs) was paused in 2023 but a successor is in late-stage legislative drafting. LADWP offers rebates for high-efficiency HVAC and induction cooktops. We track every active program and apply on your behalf.What does an ADU cost in LA?
Pricing depends on size, finish level, and site conditions. For 2026, our detached ADUs start around $250K for a 480 sq ft studio and run up to about $480K for a 1,200 sq ft custom build. Garage conversions begin around $145K. JADUs typically run $95K–$140K.What's included in your turnkey number?
Architectural and structural design, Title 24 energy compliance, full permit fees and plan check, soils report when required, foundation, framing, MEP rough-in, insulation, drywall, doors, windows, kitchen, bathroom, flooring, paint, fixtures, and final cleaning. Excluded: landscaping beyond grading, solar (offered separately), and LADWP service upgrades when the existing panel can't carry the load.Will building an ADU raise my property taxes?
Only the ADU portion is reassessed at its construction cost — the existing main house keeps its Prop 13 basis. On a typical $280K ADU, expect a property tax increase of roughly $2,800/year at LA's 1% rate plus local assessments.Can I rent my ADU on Airbnb?
Short-term rentals (under 30 days) are restricted in the City of Los Angeles to your primary residence and require Home-Sharing Ordinance registration. ADUs built after 2017 are generally ineligible for STR registration. Long-term rentals (30+ days) are permitted in nearly all jurisdictions without restriction.
Reference desk · Finance
More answers from the California reference desk
City-specific questions pulled from our 5,000-answer FAQ corpus — every link opens a deeper desk page.
What financing options work best for a ADU in Beverly Hills?
Four paths cover almost every Beverly Hills ADU: (1) HELOC if you have 30%+ equity and want flexibility, rates 8.0–9.5%; (2) cash-out refinance if your existing rate is above 6.75%; (3) renovation loan (Fannie HomeStyle / FHA 203k) that funds against future appraised value — useful when current equity is thin; (4) construction-to-perm if the scope is over $200K. CalHFA ADU grants of up to $40K are exhausted but the program may renew — check before assuming.What ROI should I expect from a ADU in Beverly Hills?
A rented ADU in Beverly Hills typically produces 9–12% cash-on-cash return after operating costs — driven by $3,400/mo for a one-bedroom and $4,800/mo for a two-bedroom at current Beverly Hills rents. Run the math on $165K as a baseline and your specific size and finish on top.How much cash do I need upfront for a ADU in Beverly Hills?
Most homeowners in Beverly Hills fund 15–25% in cash and finance the rest. On a project starting at $165K, that's roughly $25K–$45K of liquid funds for design, permits, deposits, and the first draw before the construction loan starts cycling. Reserve an additional 8–12% contingency you don't touch unless triggered.Will a ADU appraise for what I spent in Beverly Hills?
In Beverly Hills, ADU appraisals typically recognize 70–95% of construction cost in added value, with the rest captured through rental income on the income-approach side. The comp pool matters more than the spec — three similar nearby transactions in the last 6 months drive the appraisal more than any single material choice.Is a ADU in Beverly Hills tax-deductible?
Construction on your primary residence is not directly deductible on federal taxes. Three indirect paths matter: (1) HELOC or refi interest on funds spent improving the home is deductible up to the $750K mortgage cap; (2) capital improvements add to your cost basis and reduce capital gains at sale; (3) energy-efficiency upgrades (heat pump, insulation, solar) qualify for federal IRA tax credits through 2032. Consult a CPA on your specific Beverly Hills property tax exposure.What financing options work best for a garage conversion in Beverly Hills?
Four paths cover almost every Beverly Hills garage conversion: (1) HELOC if you have 30%+ equity and want flexibility, rates 8.0–9.5%; (2) cash-out refinance if your existing rate is above 6.75%; (3) renovation loan (Fannie HomeStyle / FHA 203k) that funds against future appraised value — useful when current equity is thin; (4) construction-to-perm if the scope is over $200K. CalHFA ADU grants of up to $40K are exhausted but the program may renew — check before assuming.What ROI should I expect from a garage conversion in Beverly Hills?
A rented garage conversion in Beverly Hills typically produces 9–12% cash-on-cash return after operating costs — driven by $3,400/mo for a one-bedroom and $4,800/mo for a two-bedroom at current Beverly Hills rents. Run the math on $165K as a baseline and your specific size and finish on top.How much cash do I need upfront for a garage conversion in Beverly Hills?
Most homeowners in Beverly Hills fund 15–25% in cash and finance the rest. On a project starting at $165K, that's roughly $25K–$45K of liquid funds for design, permits, deposits, and the first draw before the construction loan starts cycling. Reserve an additional 8–12% contingency you don't touch unless triggered.Will a garage conversion appraise for what I spent in Beverly Hills?
In Beverly Hills, ADU appraisals typically recognize 70–95% of construction cost in added value, with the rest captured through rental income on the income-approach side. The comp pool matters more than the spec — three similar nearby transactions in the last 6 months drive the appraisal more than any single material choice.Is a garage conversion in Beverly Hills tax-deductible?
Construction on your primary residence is not directly deductible on federal taxes. Three indirect paths matter: (1) HELOC or refi interest on funds spent improving the home is deductible up to the $750K mortgage cap; (2) capital improvements add to your cost basis and reduce capital gains at sale; (3) energy-efficiency upgrades (heat pump, insulation, solar) qualify for federal IRA tax credits through 2032. Consult a CPA on your specific Beverly Hills property tax exposure.What financing options work best for a JADU in Beverly Hills?
Four paths cover almost every Beverly Hills JADU: (1) HELOC if you have 30%+ equity and want flexibility, rates 8.0–9.5%; (2) cash-out refinance if your existing rate is above 6.75%; (3) renovation loan (Fannie HomeStyle / FHA 203k) that funds against future appraised value — useful when current equity is thin; (4) construction-to-perm if the scope is over $200K. CalHFA ADU grants of up to $40K are exhausted but the program may renew — check before assuming.What ROI should I expect from a JADU in Beverly Hills?
A rented JADU in Beverly Hills typically produces 9–12% cash-on-cash return after operating costs — driven by $3,400/mo for a one-bedroom and $4,800/mo for a two-bedroom at current Beverly Hills rents. Run the math on $165K as a baseline and your specific size and finish on top.
Sources & further reading
- California Government Code §65852.2 — statewide ADU framework (ministerial review, 60-day clock).
- LADBS — Accessory Dwelling Unit information bulletins and current permit fee schedule.
- HCD — California Department of Housing & Community Development, ADU handbook (2024 update).
- Internal data: aggregated from real California ADU and residential construction projects, 2018–2025.
Continue your read · the editorial path
We chained these chapters in the order LA homeowners actually need them. Each one picks up where the last one left a question open.
02 / 03
Finance · 7 min
Will your ADU trigger a property tax reassessment?
Under Prop 13 and BOE Rule 463, only the new construction value is reassessed — not the entire property. A practical walkthrough of how the LA County Assessor calculates the bump.
Read chapter →03 / 03
Finance · 7 min
What an ADU actually rents for in LA in 2025
Long-term, mid-term, and short-term rental yields by neighborhood — and why the headline ROI you see in marketing is usually 30% optimistic.
Read chapter →
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