ADU Financing Guide

How to Finance Your ADU

You don't have to pay cash upfront. Most homeowners use equity they already have in their home to fund their ADU build. Here's how it works.

The Most Common Ways to Finance an ADU

If you own your home and have built up equity over the years, you likely have more financing options than you realize. Here are the four most popular paths Utah homeowners use to fund their ADU projects.

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Fixed Payments

Home Equity Loan (Second Mortgage)

A home equity loan gives you one lump sum upfront at a fixed interest rate. Your monthly payment stays the same for the life of the loan, making it easy to budget. Great for homeowners who want predictability.

Typical RateFixed, varies by lender
Loan Term5 to 30 years
DisbursementSingle lump sum at closing
Typical LimitUp to 85% of home equity
Fixed rate, predictable payments
Simple one-time disbursement
You pay interest on full amount immediately
Less flexible than a HELOC
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Refinance Option

Cash-Out Refinance

You replace your existing mortgage with a new, larger mortgage and take the difference in cash. Works well if current rates are favorable or you have a high-rate existing mortgage. Rolls everything into one payment.

Typical RateCurrent mortgage rates
Max Cash OutUp to 80% of home value
Loan Term15 or 30 years
Closing Costs2% to 5% of loan amount
Single monthly payment
Potentially lowest rate if timed right
Resets mortgage term and closing costs
Not ideal if current rate is low
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Build-to-Perm

Construction Loan / ADU Loan

Construction loans are specifically designed for building projects. Funds are released in stages as construction milestones are hit. Some lenders now offer ADU-specific products with streamlined approval processes for projects under $250K.

Typical RateSlightly higher than mortgage rates
Draw ScheduleTied to construction milestones
Term12 to 18 months, then converts
Down PaymentTypically 20%+
Purpose-built for construction projects
Converts to permanent loan at completion
More paperwork and inspections required
Higher rate during construction phase

How Home Equity Works for ADU Financing

Most ADU financing is based on home equity. Here's a simple breakdown of how lenders calculate how much you can borrow.

What Is Home Equity?

Home equity is the portion of your home's value that you actually own. It's the difference between what your home is currently worth and what you still owe on your mortgage. The more equity you have, the more you can typically borrow for a project like an ADU.

Most lenders will let you borrow up to 80 to 85 percent of your home's appraised value, minus what you owe on your current mortgage. This is called your Combined Loan-to-Value (CLTV) ratio.

Example Calculation

Current Home Value$600,000
Lender Max CLTV (85%)$510,000
Remaining Mortgage Balance- $300,000
Available to Borrow$210,000

In this example, the homeowner could potentially access up to $210,000 to fund their ADU build. Actual amounts depend on credit score, income, and lender requirements.

Quick Comparison

Every financing option has tradeoffs. Here is a quick breakdown to help you decide which direction to explore first.

Option Rate Type Best For Complexity
HELOC Most Flexible Variable Phased builds, flexibility Low to Medium
Home Equity Loan Fixed Predictable budgets Low
Cash-Out Refinance Fixed High equity, favorable rates Medium
Construction Loan Variable then Fixed New builds without equity High

Before You Apply for Financing

A little preparation before you walk into a bank can save you thousands. Here are the most important things to get right.

01

Know Your Credit Score

Most equity-based loans require a credit score of 620 or above. Scores above 720 get the best rates. Pull your free report at annualcreditreport.com before applying.

02

Get a Real Estimate First

Lenders want to know what you're borrowing for. Having a detailed written estimate from a licensed contractor makes your application stronger and avoids over-borrowing.

03

Shop Multiple Lenders

HELOC and home equity loan rates vary significantly between banks and credit unions. Getting 3 or more quotes can save you a full percentage point or more on your rate.

04

Factor In All Costs

Your loan amount should cover construction, permits, utility connections, landscaping, and a 10 to 15 percent contingency buffer. Surprises happen in construction.

05

Consider the Rental Math

A $150,000 ADU financed at 7% over 20 years costs about $1,160 per month. If you rent for $1,500 to $2,000 per month, the unit pays for itself and generates positive cash flow.

06

Check with Local Credit Unions

Utah credit unions often have better HELOC and home equity loan rates than big banks. America First, Mountain America, and Utah Power Credit Union are worth checking.

Financing FAQs

Can I finance an ADU if I still have a mortgage? +
Yes. Having an existing mortgage does not disqualify you. A HELOC or home equity loan sits on top of your primary mortgage as a second lien. You just need sufficient equity. Most lenders allow combined borrowing up to 85% of your home's appraised value.
How much equity do I need to qualify? +
To borrow $150,000 to $200,000 for an ADU, you generally need at least $200,000 to $250,000 in usable equity after your existing mortgage balance. Homes in the Wasatch Front have seen strong appreciation, so many homeowners have more equity than they realize.
Does an ADU increase my home's appraised value? +
Yes, in most cases. A properly permitted ADU adds rentable square footage and income potential, both of which appraisers factor in. Many Utah homeowners see their home value increase by 20 to 30 percent after adding an ADU, which can also free up more equity for future projects.
How long does it take to get approved for a HELOC? +
HELOC approvals typically take 2 to 6 weeks from application to funding. This includes a home appraisal, underwriting, and closing. Starting your financing process early, before construction begins, keeps your project on schedule.
Is the interest on a HELOC or home equity loan tax deductible? +
Interest may be deductible if the loan is used to substantially improve your home. An ADU generally qualifies as a home improvement. Consult a tax professional to confirm how current tax law applies to your specific situation, as rules can change.
What if I don't have enough equity? +
If your equity is limited, a construction loan or ADU-specific loan product may still be available to you. Some lenders offer loans based on the projected after-renovation value of your property. A garage conversion at $50,000 to $120,000 may also be achievable with a personal loan or smaller HELOC.

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