Top 7 ADU Trends 2024: An Idaho ADU Builder’s Perspective

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ADUs are a real estate trend that is here to stay. Originally a great option in areas with higher than average housing costs or for families looking to earn extra income, ADUs gained greater traction during the pandemic in 2020 and 2021 as families spending more time at home used them to increase their livable space. 

In 2022 and into 2023, the continued popularity of ADUs has been aided by the soaring interest rates and rising cost of living, not only in large cities, but also in mid-size cities, like Boise, Idaho and in suburban areas across the United States. 

Recent ADU Legislation

This year state legislatures, local municipalities, and even the Federal Housing Administration have created new rules and regulations making it easier to build an ADU. Earlier in 2023 Idaho passed a law that prohibited HOAs statewide from banning the building of ADUs in owner-occupied homes. Although this law focused on ADU conversions, as opposed to a separate building, the implication is still one that points to the growing popularity of ADUs.

The city of Boise passed a new zoning code with changes to the owner-occupancy requirements, fewer parking space regulations for ADUs, and even an increased maximum allowable size for an ADU built in the city limits.

In October 2023, California passed new legislation allowing homeowners in participating cities to sell their ADUs following rules similar to those that apply to condominiums. While this isn’t a new concept in the US, it’s another indication of the growing trend of homeowners investing in ADUs.

Also in October 2023 the federal government got involved in the ADU trend with the announcement from the Federal Housing Administration that ADU income may now be included in underwriting for mortgage applications. 

These recent changes in legislation paired with all the potential benefits of building an ADU are all signs that the ADU trend we’ve been seeing over the past several years is really just getting started.

So as the trend in ADU building heats up, what can you expect to see in the new ADUs being built? Here are some of the top ADU trends we expect to see in 2024.

ADU Trend #1: Building With Accessibility In Mind

Multigenerational housing is one of the most common uses of an ADU. Multigenerational housing doesn’t necessarily mean that an ADU is always used for older relatives; however, building an accessible ADU means that the option is available to use your accessory dwelling unit as housing for an older parent or relative. (Interested in multigenerational housing? Learn more about building a multigenerational home.)

Building an accessible ADU also fits with another use case we’ve seen of homeowners moving into their ADU to age in place in their current location while renting out the primary residence as a way to generate additional income in retirement. Building an accessible ADU from the start keeps these options available for ADU owners without having to make updates or retrofit to improve accessibility at a later date. 

What does building an accessible ADU entail? It means incorporating features like doors that are at least 32” wide, ensuring the ADU is built with ample lighting – both natural light and lighting fixtures, and eliminating stairs by opting for a single level ADU. Accessibility also includes smaller touches like using ADA approved comfort toilets in the bathrooms and making sure any outdoor walkways and entryways are well lit.

At Pathway Builders all of our ADU plans automatically include accessibility features like comfort toilets and are single level plans designed with accessibility in mind. All of our ADU options are also customizable so that you can add the accessibility features that are most important for you as the owner.

Whether it is for an aging parent or aging in place, ADUs are becoming a more popular option for older generations and we don’t see the trend of building accessible ADUs slowing down any time soon.

ADU Trend #2: Expanding Square Footage

According to a survey conducted in September 2023 by OnePoll in conjunction with Villa Homes, an ADU builder in California, the number one reason for ADU owners to build an ADU is to increase the square footage of their homes. 

If you are in the Boise area, you may have heard of changes to the zoning code impacting ADUs – parking and owner-occupancy requirements, and an increased maximum size. Previously the maximum size of an ADU in Boise was restricted to 700 square feet; however, the most recent zoning code change makes the new maximum size 900 square feet.

Boise isn’t alone, Garden City also recently passed legislation allowing for larger ADU sizes, and these changes go beyond southwestern Idaho. Pair the increasing maximum sizes being allowed across the US with the desire for additional square footage and we expect to see the size of ADUs increase.

No matter what reason you have for building an ADU, if your lot size allows, it makes sense to maximize the additional space you have. As a rental, a larger ADU typically means the ability to charge a higher rent. If you’re using your ADU to expand your family’s living space it also makes sense to maximize the size of that added space. When planning to use the ADU as long term housing for your relatives, a larger ADU gives your relatives more of their own private space and allows you to add features like a second room with a door or even an additional bathroom or half bath. 

For anyone already investing in building an ADU, maximizing the square footage of their ADU makes sense and that’s why we expect to see the continued expansion of ADU sizes in 2024.

ADU Trend #3: Increased Storage Space

Along with the expanding square footage, the increased use of ADUs as an affordable housing option means building an ADU as a residence rather than a short term rental is likely to become more common. This means adding features to an ADU that a traditional residence needs, including storage space.

We expect to see more ADUs built with walk-in closets and kitchen pantries to incorporate additional storage space that makes the ADU more appealing for long term residency. Even if an ADU is being built in the traditional sense to host short term guests or to generate short term rental income, the additional storage space can be locked off and used as additional storage space for primary homeowners. 

Because of the additional benefits offered by increasing the storage space in an ADU floor plan, expect to see more ADUs built with added storage space in 2024.

Trend 4: Garage Attached ADUs & ADU Garage Conversions

For some homeowners adding a separate unit to their property is not an option. This may be due to zoning restrictions, financial constraints, or space limitations. When these constraints exist, homeowners can still take advantage of the benefits of an ADU with an ADU garage conversion or by attaching an ADU to their garage, similar to our Pinewood shop house floor plan.

Additionally, the new 2023 FHA regulations around incorporating ADU income into underwriting includes this specifically about garage ADUs: 

“Use 50% of the estimated rental income, for some borrowers, from a new ADU the borrower plans to attach to an existing structure, such as in a garage or basement conversion, to qualify for a mortgage under FHA’s Standard 203(k) Rehabilitation Mortgage Insurance Program.” (Source: HUD)

Add to this the fact that Google searches for “ADU garage” has been one of the top search terms related to ADUs over the past 12 months in the US (Source: Google Trends). All this points to an increase in the popularity of garage attached or garage conversion ADUs in 2024 and beyond.

For homeowners who don’t plan to add an ADU or convert their garage right now, incorporating certain features into the garage of a new home build could save time and money in the long run should a garage conversion be considered in the future. This means things like pre-plumbing and insulated garages. At Pathway Builders, all of our custom house plans include insulated garages as a standard feature, so our customers don’t have to worry about adding this as an upgrade option to ensure their garage may be more conversion ready in the future.

One other reason we see the garage ADU trend continuing in 2024 is the extra cost to finance a new ADU structure given the current interest rates. For people looking to expand their space or bring in rental revenue at a lower initial cost, a garage attached ADU or ADU conversion may make the most sense.

ADU Trend #5: Incorporating Flexible Spaces

There are so many potential uses for an ADU that it makes sense to build an ADU that incorporates multipurpose and flexible spaces. This may mean adding a second bedroom into an ADU, as we have done in our Piedmont ADU floor plan, that can bring in additional rental revenue when it functions as a second bedroom or be used as a home office when adult children are living in the ADU. 

Making sure that an ADU is built to fit a variety of uses to match the needs of potential renters, family members, or for use as additional space for owners of the primary residence, can also add value if the property is sold in the future. This makes building ADUs with more flexible space a more appealing and enduring trend that we see continuing in 2024.

ADU Trend #6: Added Outdoor Elements

This ADU trend goes along with general home trends that really gained traction during the pandemic when homeowners focused more on updating their spaces both indoor and outdoor. Incorporating an outdoor element when building an ADU not only enhances the experience, but it can also make the space feel larger, and when used as a long term residence, improve the quality of the residence. 

For these reasons, we expect to see more ADUs built with the addition of dedicated outdoor spaces like a porch, deck, or balcony. We also expect to see more tailored ADU landscaping. Landscape design can play a huge role in improving the living experience through enhanced outdoor spaces and the ability to create privacy for both the primary homeowners and ADU residents. Our Piedmont ADU floor plan is a great example of this trend as it includes a dedicated front porch to enhance the outdoor living space of this ADU option.

ADU Trend #7: Customization

The last ADU trends we expect to see more of in 2024 is customization. This trend applies whether an ADU is being retrofitted into an existing space or being built new. Because there is such a diverse range of uses and every homeowner’s reasons for building an ADU may be different, being able to adjust and adapt an ADU plan to fit specific needs will continue to grow in line with the popularity of ADUs.

Another reason we expect the customization trend to continue to grow is because every property is unique, when you pair this with different zoning regulations in different areas of the United States and even in a smaller region like our own Treasure Valley in Idaho, it means it’s difficult to create a one-size fits all ADU floor plan.

Sure there will be plans that are closer to what you might want, but being able to customize an ADU completely allows homeowners to tailor their ADUs to their own specific uses, property, style, and location. 

As a custom home builder, all of our ADU home plans are completely customizable for this reason. Whether it’s expanding the space to maximize the square footage allowed on your property or as simple as adding an additional outlet, we work with all of our customer’s to build the ADU that’s best for their unique needs. We even have the option to get started on this customization using our instant quote tool. All you need to do is select a starting home plan and pick the features you want to get a custom price quote for your ADU. 

If we don’t have a plan that aligns with your current needs we can also help you create a completely custom ADU plan just for you.


There are so many benefits to building an ADU. Whether building an ADU to create a multigenerational living space or to create an income generation opportunity, there are many reasons for homeowners to consider building an ADU in 2024. It’s why we are seeing the ADU trend continue to grow and expect the growth to continue over the next year. Hopefully these ADU trends for 2024 will help you as you consider the features you want to incorporate into your ADU build.

If you are in southwestern Idaho, contact us to learn more about building an ADU in Boise, Eagle, or surrounding areas or take a look at our ADU plans and start customizing your ADU build today.