Step 08 · Plan the money
The construction is well understood. The financing is where ADU projects most often stall, because an ADU does not fit neatly into the products lenders already had.
The short answer
ADUs are usually financed by cash, a home equity loan or HELOC, a renovation or construction loan, or a cash-out refinance.
Which is available depends on your equity, income and credit, and on whether the lender will count future ADU rent.
Terms vary by lender and change over time — this is general information, not financial advice.
HyreADU is not a lender, broker or financial adviser, and nothing here is personalised financial advice. Rates, terms and product availability change; confirm everything with the lender.
What moves it
Each asks something different of you.
No underwriting, no interest, no draw schedule. The constraint is obvious and it is why most projects use something else.
Borrows against equity you already have. Usually the simplest to arrange where the equity exists; the amount is capped by it.
Underwrites against the value after completion rather than the equity today, and releases money in draws against inspected progress. More administration, and the route that works when present equity is the constraint.
Replaces the existing mortgage. Whether this is sensible depends heavily on the rate on the loan you would be giving up.
01
An ADU is a construction project on a property that already has a mortgage, and it produces an asset that is difficult to value separately and cannot be sold separately.
That combination sits awkwardly across existing lending products. Our financing landscape research sets out the structural reasons in detail; the short version is that the problem is product design, not your application.
02
California’s CalHFA ADU Grant Program offered assistance toward pre-development costs. Our research on it makes a narrower point that is still worth knowing: the program data is not published in a form that allows independent verification of who received what.
We record that as a limitation rather than filling the gap with an estimate. Check the program’s own current status before relying on it — grant programs open, close and exhaust their funding.
03
Two things make the conversation productive. Know your approximate total project cost including fees, not just construction. And know whether you are asking the lender to count future rental income, because that single question sorts which products are available to you.
The financing comparison tool runs the four routes side by side on a rate you have actually been quoted, rather than on a market average we would have to guess at.
Go deeper
ResearchOriginal analysis
StatisticsSourced figures
ToolsRun your numbers
Commonly, yes — through a home equity loan or HELOC, a renovation or construction loan, or a cash-out refinance. Availability depends on your equity, income and credit, and on the lender’s treatment of ADUs. We are not a lender and cannot tell you what you will qualify for.
Some will and some will not, and the treatment differs between products and over time. It is one of the first questions to ask, because it changes which products are open to you. Get the answer in writing from the specific lender.
That depends on your construction cost, local rent, vacancy, financing terms, operating costs, taxes and insurance — and on how long you hold it.
We publish sourced evidence on rents and on appraisal treatment, and our ROI calculator runs three rent scenarios on your own cost.
We do not publish a return figure, because a general one would be meaningless.
Plan your project
Three short steps: the ADU you want, your home, and how to reach you. Nothing goes to a contractor unless you agree.
A straight answer: our ADU professional matching is still being built, so this is not a quote service, and we cannot tell you whether your lot qualifies. We can help you work out which questions to ask and what a thorough proposal should contain. Your planning department decides what is permitted at your address.
Get ADU Options
Tell us about the ADU you are planning and where you are. We will follow up about connecting you with contractors serving your area.