Sustainability for San Diego ADUS, Granny Flats, & Casitas in 2025
The idea of sustainability in homebuilding and remodeling is receiving more attention than ever. It’s easy to understand why. The combination of ROI realized in increased home value, lower utility bills, and the rewards of good environmental stewardship make building-in sustainability an easy decision.
This Specialty Design Build article offers ideas and advice for building sustainable ADUs, granny flats, and casitas in San Diego.
Passive House Design or Net-Zero Design for Your San Diego Home Build or Addition
The ultimate in sustainable home and home addition construction is passive house design, AKA net-zero design.
A newer term in the construction industry, passive or net-zero homes create more energy than they use. Your net-zero home will not only have power in the event of a blackout or brownout—it could even be off-grid and still function perfectly.
Using the net zero approach yields many attractive benefits if you build an ADU or granny flat in San Diego.
Net-Zero ADU Builds Can Save on Utilities and Even Property Taxes
Having a casita on your property will require additional energy. Not only will passive house design help eliminate higher bills (and we all know energy is not cheap here in California), but it may even get you tax breaks or discounted energy bills on the rest of your property.
Building an ADU or Casita in San Diego that conforms to net-zero home-building standards and delivers the rewards you’re after requires a bit more planning and upfront investment. However, this route pays dividends that make a bit of extra planning well worth it. Net-zero homes are better for both your financial health and the health of our planet.
Considerations when building a sustainable ADU or granny flat:
- Working with a builder experienced in net-zero construction is essential.
- Additional planning and investment can pay off in long-term savings and home value.
- Advantages include lower energy bills, tax incentives, and even discounted energy bills.
Elements of a Net-Zero ADU, Granny Flat, or Casita Build in San Diego
Solar Panels: A Key to Unlocking Sustainable Building Benefits
The greater San Diego area is an ideal place to take advantage of solar energy’s many benefits. A net-zero sustainable build is even easier with smaller-scale construction. An ADU or casita can often be completely powered with a few solar panels.
If you are interested in learning more about solar power regulations and energy buy-back here in California, make sure you take some time to understand the new rulings that came into effect in April with the introduction of NEM 3.0.
Working with a sustainable building partner like Specialty Design Build simplifies this process and helps ensure success and avoid costly mistakes.
Maximize Sustainability with the Right Insulation, Doors and Windows
Although San Diego is famous for its mild climate, using the right insulation, glass sliding doors, and windows is important if you plan on building a net-zero ADU or granny flat. San Diego gets warm enough to call for air conditioning, and many of us use the heat at least some of the time in the winter months.
Insulating Your Net-Zero ADU or Casita
Using high R-value (R30 or higher) rigid foam insulation on the exterior walls is one way to improve the efficiency of your HVAC system and keep temperatures stable. If your ADU or granny flat will have an attic or roof space, consider dense-pack cellulose insulation with an R-value of R-60 or higher.
Energy-Efficient Glass and Doors for Your Sustainable Build
Choose windows with low-emissivity (Low-E) coatings to reduce heat transfer. Triple-glazed windows provide excellent insulation, which will meaningfully reduce energy use. Solar shading, like fixed or dynamic window shades, should also be considered, and south-facing windows should be installed where possible. Use energy-efficient doors with solid cores and add weatherstripping to avoid drafts.
Use Energy Storage Systems to Complete Your Solar Net-Zero Build
If you are installing solar panels, you should definitely consider adding an energy storage system to complement them. Several home energy storage systems are on the market, including one made by the guy who bought the company formerly known as Twitter.
Energy Storage Systems vs Gas Backup Generators
Storing the energy your home produces is very similar to having a backup generator, but it’s electrically powered instead of gas-powered. Electrical generators are a more sustainable energy source than gas, but they can also be more cost-effective upfront and in the long run, as you don’t have to purchase fuel for them.
Pros and Cons of Energy Storage Systems for Your San Diego ADU Build
Energy storage systems are also quicker to install and significantly quieter than gas generators while providing similar benefits. The only thing they aren’t better at is long-term energy powering solutions because they don’t store as much energy as a generator can continuously produce.
Accessibility is Sustainability
Consider longevity. Design your ADU or granny flat now so that it is usable for a human lifetime. Plan for things like grab bars or wheelchair clearance. Do everything you reasonably can to avoid future remodels. Avoiding future home improvement projects is the most sustainable thing you can do when building a casita or granny flat in San Diego.
Sustainable Landscaping and Native Plants
We don’t have a lot of water to spare here in California, so designing the landscape around your casita with native plants that don’t require a lot of irrigation is key. A non-traditional, non-grass lawn yard is the best way to have a sustainable landscape.
Native plants will thrive in the temperature and climate of their area. You don’t have to do much for these plants to help them thrive. They also grow their roots much deeper than non-native plants, which helps avoid things like landslides. And guess what – San Diego may even compensate you for removing your turf lawn.
You can also plan your landscaping to collect rainwater (we have so much of that in San Diego—an average of 10 whole inches per year!) and use it as a source of irrigation for your yard. Using recycled materials such as concrete or natural stone to create a pathway in your yard is an extra bonus sustainability!
10 Native Plants for Sustainable Landscaping in San Diego
- Sage (Salvia): Various species like Cleveland sage, white sage, and purple sage.
- San Diego Monkeyflower (Diplacus aurantiacus): Bright orange flowers that attract pollinators.
- Succulents: Various types including agave and aloe.
- California Fuchsia (Epilobium canum): Vibrant red-orange blooms.
- California Poppy (Eschscholzia californica): State flower with bright orange petals.
- Desert Mallow (Sphaeralcea ambigua): Showy yellow-orange flowers.
- California Lilac (Ceanothus): Dense clusters of blue-purple flowers.
- Ian Bush Manzanita (Arctostaphylos ‘Ian Bush’): Evergreen shrub with red bark.
- Showy Penstemon (Penstemon spectabilis): Tall spikes of tubular flowers.
- Narrowleaf Milkweed (Asclepias fascicularis): Essential for monarch butterflies.
Standard California Permitting Requirements
Ensuring your new ADU, casita, or granny flat build complies with the rules and regulations is a must. Make sure you’re aware of the rules and that you have the necessary permits in place. California has tons of items that must be tacked onto projects as part of getting them permitted, and we embrace them.
They include:
- Solar panels on certain new structures
- Mandatory recycling and reporting of a certain percentage of waste on projects
- Low-flow plumbing fixtures and restrictions on the number of fixtures in a shower
- The most stringent requirements for energy-efficient windows and doors in the nation
- Title 24 energy requirements such as high efficacy lighting, motion and moisture sensors on certain fixtures such as exhaust fans and lighting
- Increased insulation depending on climate zones, cool roofing, radiant barriers, concrete flooring, HERS testing, etc.
Speciality Design Build for Sustainable, Net-Zero ADUs and More
We hope you found our article about making your ADU/granny flat/casita a more sustainable building helpful. If you have any questions about the feasibility of these ideas or are ready to start designing your San Diego ADU, please contact us. We’d love to talk to you about your project.
Our streamlined design-build process makes planning easy. The services of San Diego’s most talented home and interior designers are all part of the package. Every home addition we design considers our client’s needs to ensure that every inch is utilized to its best potential for years to come.
Be sure to visit our Cost & Value calculator for your addition here.
Contact us today to begin planning your sustainable build today!
San Diego (858) 759-7400
North County (760) 738-6270
