Your new accessory dwelling unit (ADU) will increase the overall power usage of your home. To offset this, many people choose to add solar panels on their ADU’s roof. In fact, some new ADUs in California are required to have solar panels under Title 24. So, you should determine whether you have to have solar panels and, if you don’t, whether it will benefit you to add them anyway. Here are some things to consider before you make your decision.

Are Solar Panels a Requirement for Your ADU?

In California, the law requires solar panels on many new construction buildings, from commercial buildings down to small ADUs. Your local laws may differ from the state laws. However, in general, new detached ADUs will require you to add solar panels. You do not need to necessarily add the panels directly to the ADU’s roof. Adding some panels to the main property can also fulfill your legal requirements.

You do not need to add solar panels to all ADUs. ADUs that are usually exempt include:

  • Shaded ADUs: ADUs that are shaded, by pre-existing sources, so that they have annual solar access less than 80 contiguous square feet, do not need ADUs.
  • Attached ADUs: ADUs that are attached to your house are considered home additions and therefore do not need solar panels.
  • Converted ADUs: If you have an existing space in your home that you are converting to an ADU you typically do not need to add solar panels.

That said, you should check with your local building codes to discover for sure whether your ADU will require solar panels.

Benefits of Solar Panels on ADUs

So, your ADU doesn’t require solar panels. Should you get some anyway? There are benefits to adding solar panels, including:

  • Handle demand: When you add an ADU you are increasing electrical demands on your home. Sometimes instead of making adjustments to the home’s electrical system, you can keep your ADU’s system separate and use solar panels to supply it.
  • Improved value: Solar panels can increase the value of your ADU and, therefore, your whole property, depending on your market.
  • Lower costs: Solar panels can reduce or even eliminate your electrical bill, depending on how much energy you use.

Disadvantages of Solar Panels on ADUs

Of course, you should also consider the potential disadvantages you would experience from installing solar panels on your ADU. They include:

  • Increased cost: Solar panels can be a considerable investment which may push your ADU out of your budget range.
  • Long ROI: You should calculate carefully if your solar panels will give you a return on investment. If your lowered utility bills will pay off your investment cost for your solar panels in 15 years, but they are only going to last ten years, then you are not really saving money.

Get Professional Guidance

When you’re making any design decisions for your ADU, it is helpful to have a professional’s advice. ADU designers and builders can let you know if your specific ADU will require solar panels under California law, help you make adjustments so it will not, or help you sort out whether adding solar panels to your ADU may benefit you.