If you are building, or planning to build an ADU then one important consideration is how you are going to get electricity to your ADU.
ADUs are meant to be accessory or extra dwelling units apart from the primary residence therefore, electricity is not only recommended, but often required by most cities.
How to Get Electricity to my ADU?
The four most common ways to supply your ADU with electricity are:
- Connect your ADU to the power supply of the primary residence
- Create a separate power supply for your ADU
- Using solar energy to power the ADU
- Using a generator to power your ADU
These are the four most common ways that people choose to power their ADUs. Each of these options has pros and cons that can vary depending on what your needs are. More details are given below that will help you decide how to get electricity to your ADU.
4 Ways to Power Your ADU
Supplying your ADU with electricity is not only helpful to those occupying the space, but often required by your city. The following are the four most common ways to supply your ADU with electricity and how each method can be used to meet your specific needs.
1. How to Use Your Primary Residence to Power Your ADU
Utilizing the power supply from the primary residence to power the ADU is the most common way that people choose to power their ADUs.
If the accessory dwelling unit is meant to be an extra living space for your family, then borrowing power from your primary residence makes the most sense. Even if you decide to move into your ADU and use your primary residence/main house as an AirBnB or as a rental for another tenant, you can still connect the ADU’s power supply to the main house.
However, if you do plan on renting out your main house, and keeping your ADU powered by the main house, then you will want to disclose this to your tenant in order to split the electric bill accordingly.
With that being said, before you can connect the two units, you will first need to check your power supply to the main house. Amperage is the amount of electric power that you have coming into the house.
An ADU may need up to 100 Amps to operate and your primary dwelling unit will most likely have a total amperage of between 60 Amps and 200 Amps. Of course, the more amperage you have being supplied to your home the more devices you can run at the same time.
Needless to say, it is very important for you to consider the amperage of your home before connecting it to your ADU.
Therefore, you should check with your electrician to see whether you have enough amperage in the main house to share with your ADU. If there is not enough power coming into your main house, you may have to update the system first before connecting the power supply from your main house.
Install an Electrical Subpanel for the ADU
Once your electrician has confirmed that there is enough power for use in the main house, you will have to install an electrical sub panel for the ADU. The electrical panel is the meter box that is usually mounted to the exterior of the house. Inside the panel, you will find the circuits and breakers as well as the amperage ratings.
The sub panel is going to house all the circuits and breakers for the ADU. Therefore, you can control the power usage in the accessory dwelling and in the primary dwelling unit separately without one affecting the other.
However, since the ADU gets its’ power supply from the main house’s panel, its’ power supply can still be controlled and switched on and off from the panel of the main house.
Utilizing your primary dwelling to power your ADU is a great idea for people who plan to use both the ADU and their primary residence. This can include individuals with aging parents who will be using the ADU or families with older children who will be living in the ADU.
Each circumstance is unique, but if you or someone that you are taking care of will be using the ADU, then this is the best option for you as the power can easily be divided and shared between the two units.
2. How To Get Electricity To My ADU Using Separate Power Services
In certain cases, it makes more sense to set up a separate power service for your ADU. One such reason for using a power supply separate from the main house is that the primary dwelling unit does not have enough amperage to share with an ADU.
Another reason you may want to have separate power supplies is if you plan to rent the ADU out long-term.
In either case, you will need to install a dual meter panel on the main house if you want to get electricity to your ADU using separate power services.
Once you have installed a dual meter panel on the main house, you will then need to run a new electrical service to the dual meter box that will power the two meters.
One important thing to consider when wiring the two meters is that the electrical feed from the dual meter panel to the ADU is not allowed to pass through or under the main house. This is because each unit will need to have the capability of being serviced separately without one interrupting the other one.
If you are using the ADU as an Air BnB or for a family member then dividing the electric bill is not something that would concern you. But, if you plan on renting the ADU to a tenant then it may make life easier for you to separate the electrical supplies and allow the tenant to be responsible for their own electric bill each month.
However, creating a power supply for your ADU that is separate from the main house is not cheap. Several things such as purchasing a new panel, creating a new electrical service and wiring can all add up.
Although this option can be more expensive, it may save you the hassle of having to chase down your tenant each month and ask them for their portion of the electric bill.
3. Powering Your ADU with Solar Energy
Solar energy has become increasingly popular over the past few years given that it helps the environment and can drastically decrease your electric bill.
The initial cost for buying and installing solar panels, battery packs and other accessories can be high (around $7,000 for an ADU) which may make it difficult for some to afford.
However, in most cases, this is a one time price to pay that will be offset by a much lower electricity bill.
If you are constructing a brand new ADU then you will want to decide early on if you want to power your ADU using solar energy. This will allow you to design the ADU in such a way that the solar panels are able to maximize the energy from the sun.
In fact, beginning on January 1st 2020, you will be required to have solar panels on your ADU if you live in California. This means that if you live in California, designing your ADU for solar energy capability is not only a suggestion, but a requirement.
If you are considering solar then the best thing you can do is to consult with your local solar company to find out whether solar energy will be a viable option for your ADU. You can even get a free, no-obligation quote for the entire solar installation job.
In my personal opinion I recommend going solar whenever possible. You may have to pay a lot upfront, but having that low electric bill will pay off in the long run.
4. Using a Generator
Using a generator is another option to power your ADU; however I recommend only using this option if you use your ADU infrequently or in case of emergencies.
When choosing a generator there are two types: portable and standby.
Portable generators are best for when the power goes out and you need electricity in your home. These generators are gas powered and can easily plug into your sub panel or appliances. These generators typically cost between $500 and $1,500 depending on the power output.
Standby generators are another option to power your ADU. These generators are powered by gas or propane and will kick in automatically if the power ever goes out in your ADU.
These generators will typically cost between $5,000 and $7,000, including installation, but are great if your house often loses power.
Again, using a generator to power your ADU is an option, but is not an advisable long term solution.
Final Thoughts
There are several ways to get electricity to your ADU and just listed the four most common.
Whether you want to install a dual meter panel and have your accessory dwelling unit be powered independently, keep the meter you do have and connect to the main house for power or you want to go solar to cut down on the electric bill, you now have a better understanding of the pros and cons of each method.
As was stated in the beginning, the way in which you choose to power your ADU will depend on your unique circumstance and you must choose the option that works best for you.