If you recently purchased a beautiful ADU (Accessory Dwelling Unit) or are considering investing in one, you may be wondering if ADUs actually increase property value. In a housing market that is increasingly expensive, many homeowners are turning to ADUs as a way to boost their property value while benefiting from additional rental income. Yet, many confusing questions arise from investment returns to legalities. Don’t worry though, we are here to offer a clear guide on what you need to know as a homeowner about ADUs and property value, including permits, appraisals, rental income, and more. Let’s dive right in!
Do ADUs increase property value?
Absolutely! The answer to this pressing question is a resounding yes, although let’s break it down some more. On average, having a permanent ADU on your property will increase your property value anywhere from 20-30%, according to the National Association of Realtors. In certain housing markets like some areas of California, homeowners might expect to see an even higher return.
This is a significant percentage considering the relative affordability of a high-quality ADU model. If your housing market sells based on square footage, adding an constructed ADU can increase the property value greatly. For example, if the housing market in your area is selling for $400 per square foot and you have a 1,800 square foot home, your home will be appraised at $720,000. Adding a 500 square foot ADU would add an additional $200,000 to your property value in square footage alone, without even considering the potential rental income. Another way to calculate your increased property value is to multiply your property value by 20-30% to get another estimate. Either way, this means a legally permitted ADU can be an excellent investment for the value of your property!
Of course, there are many other factors that come into play when discussing permanent ADUs and property value. Below is a chart breaking down more critical factors.
| Factor | Description | Impact on Property Value |
| Permits/Legal Status | Paperwork that allows the ADU to be on the property | Necessary for increased property value |
| ADU Type | Detached ADUs are independent units while attached and conversion ADUs are part of the main dwelling while still having a private entrance. | Detached ADUs increase property value more than attached and conversion ADUs because of their privacy and extra space |
| Size and Design | Larger units with full bedrooms and bathrooms are more valuable | Larger units directly correlate to more square footage, boosting property value |
| Potential Rental Income | Monthly income adds income-based value potential | Has a much higher impact in urban areas like LA or other major cities |
| Local Market | High-demand urban and coastal areas have a greater ROI | Boosts property value in cities with a housing shortage |
| Zoning Regulations | Some areas restrict renting ADUs out or resale of ADUs altogether | Limited usage reduces buyer value perception. |
Helpful tip: Use our investment calculator to crunch the numbers on your potential ROI (Return On Investment) for your ADU!
Does having an ADU on my property make it challenging to sell my home?
Having an ADU on your property does not make it more challenging to sell your home. In fact, it may attract more buyers as the housing market shifts to more generational living options.
It is unusual that investing in an ADU will make it more challenging for you to sell your home later.
Several factors that always affect the general housing market include local market conditions, size and quality, and regulations.
- Local Market Conditions: The state of your local housing market always impacts how houses sell, with or without an ADU. If the market is in a bad place, it may be wise to wait to sell until the market quality improves.
- Size and Quality of the ADU: If the ADU is not designed well or has degenerated significantly in quality, it may be more difficult to sell the property due to perceived value lack.
- Regulations and Zoning Laws: We will discuss later the required permits for ADUs and how zoning can influence what type of ADU to purchase, but if the ADU on your property lacks the necessary permits, it will be difficult to sell. Lenders may not finance loans for unpermitted structures on a property, making it difficult to secure financing.
Can I Use The ADU On My Property To Produce Income?
Yes.
In fact, having an ADU to produce income is one of the biggest benefits of taking on a project like this.
One of the biggest appeals of a permanent ADU is the potential for rental income, particularly in areas with high average rent prices, like urban neighborhoods and cities. You could do this either in the form of long-term renting or short-term rentals like Airbnb.
Long-Term Rental
In many areas, with a legally permitted ADU, it is desired that you use your ADU as a long term rental.
This allows you to have a consistent source of income, and hand selection of choosign your neighbors.
The average rent price for a 600 square foot ADU is around $1940 a month, and in some areas, significantly more, upwards of $3500 monthly.
Whether you choose to rent out your property to strangers, family, or friends, having an ADU as a long-term rental is an excellent source of additional income.
Short-Term Rental
ADUs can be a great way to have short-term rental guests while allowing you to have some additional income while only havign the responsibility “when you want it”.
People are always traveling which means they need a place to stay. That’s where your beautiful ADU comes in as the perfect Airbnb or Vrbo short-term rental opportunity.
With the added convenience of your ADU being on your main property, you’ll be able to keep up with the maintenance, cleaning, and repairs that go into running an Airbnb. You can also use tools like AirDNA to help you calculate your potential rental income and ROI.
Is It better to do Short Term or Long Term Rentals With An ADU?
The best option depends on the clientele you want to attract and the financing or grants you qualify for. To help you decide which option is right for you, compare the choices in the table below and see which best fits your needs.
| Factor | Long Term Rental | Short Term Rental |
| Income | Consistent but lower monthly income | Sporadic but potentially higher monthly income |
| Management | Low effort and involvement | High involvement with cleaning, repairs, maintenance |
| Occupancy | Consistent, long-term renters | Renters dependent on seasons and demands |
| Regulations | Typically fewer regulations and restrictions | More permits, rules, and taxes |
| Flexibility | Lower (lease-bound) | Higher (block out certain times, adjust pricing as needed) |
Do ADUs Help Your Home Sell Faster?
In short, it depends on your local market and whether you can sell the ADU separately from your primary home. Three main factors determine whether an ADU could help your home sell faster and for a better price.
1.) Increased Buyer Demand:
Many investors and local buyers are looking for properties with ADUs because of the incredible ROI they offer. Studies from Porch.com show that over 120,000 ADUs were built in 2020 alone, a number that is much higher today. People are realizing the benefit ADUs can have and they are looking for properties that already have ADUs on them, which could help your property sell faster.
2.) Higher Property Value:
As outlined at the beginning of this article, a well-constructed, legal ADU adds significant value to your property, which local buyers are interested in. They are looking for properties that will continue to increase in value, something that an ADU continues to do.
3.) Potential for Rental Income:
In the previous section, we explained how an ADU can be used as a great source of long-term rental income or short-term rental revenue. When investors or local buyers are considering your property, this potential source of rental income will be a huge drawing factor in the process, making it plausible your property will sell quickly.
Do Appraisers Calculate ADUs Into The Value Of My Home?
Yes!
Appraisers will typically value your property containing an ADU in one of three ways.
They may compare it to other properties with ADUs, consider potential income sources, or base it on cost. Let’s break each appraisal down a bit more specifically.
Comparable Sales Appraisal Method
A skilled appraiser may estimate your home’s value by comparing it to similar properties with ADUs, as well as properties without them. This approach, known as the sales comparison method, relies on recent sales of comparable homes to help determine your property’s market value.
However, this method can be more challenging in areas where ADUs are uncommon or few comparable properties have sold. In these markets, it may be harder to determine how much additional value an ADU contributes to your home’s overall worth.
Another factor to consider is whether local regulations allow you to sell your ADU separately from your primary home. If they do, the appraiser may value the ADU as a separate property and compare it to similar properties on the market.
Income Approach Appraisal Method
The income appraisal approach is a popular method that will calculate the value of the ADU based on your net income.
The formula is Net Operating Income (NOI) divided by the capitalization rate. So if your ADU generates $15,000 of income a year and your local capitalization rate is 10%, your ADU would be valued at $150,000.
Appraisers may use this method if your ADU is being used as a rental or investment property, but it is not as common as the comparable sales method.
Cost Appraisal Method
The cost approach estimates how much it would cost to build the ADU today, then subtracts depreciation based on the unit’s age, condition, and design. This method is particularly useful when there are few or no comparable sales available.
For example, if your ADU is brand new and there are no nearby homes with similar additions, an appraiser may calculate the value based on what it would cost to construct your ADU from scratch—adjusted for wear and tear if it’s older. While not always as reflective of market demand as the comparable sales approach, the cost method provides a solid valuation benchmark in areas where ADUs are gaining popularity.
Note: Appraisers will also take into consideration external factors like views, neighborhood, condition of the house, lot size, and other related factors.
Does My ADU Need To Be Permitted To Increase My Property Value?
Yes, permitting your ADU is important if you want it to contribute to your property’s value.
Without the proper permits, your ADU may be treated as little more than a finished bonus room rather than a legal dwelling.
Unpermitted construction can also lead to fines, legal complications, and potential issues when selling your property. Buyers may be hesitant to purchase a home with an unpermitted ADU, which could affect its resale value.
The bottom line: Make sure your ADU meets local permitting requirements before installation.
Depending on where you live, your municipality may require some or all of the following permits. Keep in mind that requirements vary by location.
Zoning
First things first, you must have a zoning permit. This permit ensures that an ADU is legally allowed on your lot.
Zoning rules also regulate critical elements like minimum lot size, maximum ADU size, height limits, and whether the ADU can be used as a rental. Without zoning approval, you cannot move forward, regardless of your ADU’s design.
To help you understand your local zoning laws, review the table below.
Building
Next up in the process is the building permit which covers all the structural requirement components of the ADU.
This includes the foundation, framing, roofing, insulation, windows, etc. You will need your plans reviewed by the city or town building department, and inspections may be scheduled.
While it may seem like an added headache, the building permit helps ensure your ADU is safe and cleared for habitable use.
Plumbing
The plumbing permit covers all water supply and drainage systems in the ADU. As mentioned earlier, you will need to arrange for a sewage connection for the ADU. Whether you’re tying into the main house’s water and sewer lines or installing separate utility connections, a plumbing permit is necessary. Inspectors will often require pressure tests and line inspections before the system can be approved.
Electrical
Because you will be hooking up the ADU tiny home to electricity, you will probably need to obtain an electrical permit for any electrical work inside the ADU or for the subpanels and connections to the main electrical line. Plus if you want to do any additional electrical wiring, you will need this permit to ensure your ADU is compliant with the National Electrical Code (NEC) and any local requirements. Depending on your design, you may be able to use a shared meter with the main house or install a separate one (required in certain states like California). Along with the permit, there may be several inspections before the ADU is approved.
On the other hand, a Zook Cabin ADU will come completely certified and permitted prior to delivery, allowing you to forego the headache of chasing down all the permits by yourself.
Will A Tiny Home ADU Increase The Value Of My Home The Same As A Permanent ADU?
Tiny home ADUs typically don’t increase your property’s value the same way a permanent ADU does. This is because tiny home ADUs aren’t considered real property and would fall under the same classification as an “out building.”
However, tiny homes can be a great alternative to a traditional ADU, especially if you need a temporary place to house an elderly parent or help your young adult children launch into independence.
They can also be ideal for short-term rentals, providing additional income.
| Park Model Tiny Homes Vs. Permanent ADUs | |
| Park Models | Permanent ADUs |
| Permitted as an ADU only in certain areas that meet RVIA standards | Permitted in all areas that allow ADUs. |
| Viewed as personal property; tends to depreciate in value over time | Viewed as part of the real estate; appreciates over time like a traditional house |
| May be limited by zoning requirements for long-term living or short-term rental use | Designed for full-time living or rentals |
| More compact and movable | Permanently installed and larger |
Conclusion
Adding an ADU to your property can open the door to more than extra space. It may increase your property value, create a place for family to stay, or give you an opportunity to earn rental income.
If you’re exploring what an ADU could look like on your property, Zook Cabins is here to help you take the next step. Our ADUs combine quality craftsmanship with comfortable, inviting spaces designed to meet applicable local building codes.
Have questions about finding the right fit for your property? Get in touch or request a free quote to start exploring your options.
