Adding an accessory dwelling unit to your property is a chance to create more living space while increasing the value of your home. More and more California homeowners are choosing to build their ADUs as fully electric units. By skipping gas lines and running everything on electricity, these ADUs are safer, easier to maintain, and better aligned with the state’s clean energy goals.
An all-electric prefab ADU can be designed with efficient appliances, modern heating and cooling systems, and a wiring plan that ensures smooth daily use. It’s a practical choice that keeps operating costs predictable and makes it simple to connect with solar or other renewable energy sources in the future.
This guide walks you through the essential equipment and wiring plan for an all-electric prefab ADU, giving you a clear picture of what’s needed to build a comfortable and future-ready space.
What is an All-Electric Prefab ADU?
An all-electric prefab ADU is a self-contained living space that relies entirely on electricity for cooking, heating, cooling, and hot water. Unlike traditional builds that may use natural gas, everything is powered by electricity.
Prefab ADUs are built off-site in a controlled environment, which allows for higher quality and faster installation. Once complete, they are transported to your property and set up with the required utilities. Choosing an all-electric approach reduces the complexity of utility connections, since there is no need for gas lines.
Why Go All-Electric for Your ADU?
Going all-electric offers more than just convenience. It provides lasting value and peace of mind.
Benefits of All-Electric ADUs:
- Safety: Eliminates risks tied to gas leaks or carbon monoxide exposure.
- Lower Maintenance: Electric appliances usually have fewer service needs compared to gas-powered ones.
- Energy Efficiency: Works well with modern, high-efficiency appliances.
- Solar Compatibility: Simple to connect with rooftop or ground-mounted solar panels.
- Future-Proof: Meets California’s clean energy goals and avoids restrictions on gas usage in new construction.
Essential Equipment for an All-Electric Prefab ADU
When planning your ADU, selecting the right equipment ensures comfort and efficiency.
Kitchen Appliances
- Induction cooktop or electric range
- Convection oven and microwave
- Energy Star refrigerator
- Compact dishwasher
Heating & Cooling
- Heat pump HVAC system
- Mini-split system for smaller layouts
- Smart thermostat for temperature control
Water Heating
- Tankless electric water heater
- Heat pump water heater for higher efficiency
Laundry & Cleaning
- Compact washer and dryer combo
- Ventless dryer option if space is limited
Lighting & Power
- LED fixtures throughout
- Smart switches and dimmers
- Outdoor motion-activated security lights
By carefully choosing these appliances, your ADU will remain energy-efficient and comfortable for daily living.
Wiring Plan Essentials for an All-Electric ADU
A well-designed wiring plan is the backbone of your ADU. It ensures all systems function properly without overloading circuits.
Service Panel and Load Calculation
Every all-electric ADU requires its own subpanel. Most units need between 100 and 125 amps depending on the size and number of appliances. A licensed electrician will perform load calculations to make sure the panel can handle all circuits.
Circuit Distribution
Each area of the ADU needs separate circuits for reliability and safety:
- Kitchen: Dedicated lines for oven, cooktop, refrigerator, and dishwasher.
- Laundry: Separate circuits for washer and dryer.
- Heating and Cooling: Dedicated breakers for mini-splits or heat pumps.
- Water Heating: Individual high-capacity circuit for tankless units.
- Lighting and Outlets: Balanced across living, bedroom, and bathroom areas.
Safety and Compliance
California building codes include several important requirements:
- GFCI outlets in kitchens, bathrooms, and outdoor spaces.
- AFCI protection in bedrooms and living areas.
- Smoke detectors in every sleeping area.
- Carbon monoxide alarms for safety compliance.
Preparing for the Future
Many homeowners plan ahead when building an ADU by including:
- EV charger-ready outlets
- Pre-wiring for solar panels
- Circuits designed for future battery storage systems
A Simple Way to Picture the Wiring Plan
Think of your ADU’s electrical system like a tree. The subpanel is the trunk, circuits are the branches, and outlets or appliances are the leaves. Each branch carries power to different parts of the home, and the system only works well if everything is balanced and connected properly.
This makes it easier to understand why careful planning is required before installation begins.
Cost Considerations and Long-Term Savings
Choosing all-electric may come with a slightly higher upfront cost, but it usually pays for itself through energy savings and efficiency.
Cost Factors to Keep in Mind:
- Installation Costs: Electrical work can be more extensive but eliminates the need for gas plumbing.
- Energy Bills: High-efficiency electric appliances combined with solar often reduce monthly costs.
- Incentives and Rebates: California utilities provide rebates for heat pumps, induction cooktops, and efficient water heaters.
- Resale Value: Properties with all-electric ADUs appeal to buyers looking for modern, sustainable homes.
Nestadu’s Approach to Building All-Electric Prefab ADUs
At Nestadu, we design every ADU with functionality, safety, and comfort in mind. Our team provides:
- Custom equipment lists to fit your lifestyle and space
- Complete wiring plans handled by licensed professionals
- Units that meet or exceed California Title 24 energy standards
- Integration with smart home technology
- End-to-end service from planning through installation
With years of experience and a focus on client satisfaction, we simplify the process and deliver an ADU that works seamlessly for your needs.
Conclusion
An all-electric prefab ADU is a smart investment for homeowners looking to expand their property with safety, efficiency, and future readiness in mind. With the right equipment and a well-designed wiring plan, your ADU can serve as a guest suite, rental unit, or family living space that remains comfortable for years to come.
Nestadu is here to guide you through each step of the process, from appliance selection to wiring and installation. If you’re ready to bring your vision of an all-electric prefab ADU to life, our team is prepared to make it happen with careful planning and quality craftsmanship.
