Frequently Asked Questions
Deciding if Solar is Right for Your Home
Frequently Asked Questions about Solar In San Francisco
What is the first step I should take when looking into solar?
Start with your electricity usage. How much electricity have you been using? When are you using it (time of day and season)? How much do you pay for electricity? Has your usage been increasing or decreasing? This information is critical to sizing your solar energy system.
Is my roof good for a solar electric system?
Shading, roof orientation, aesthetic concerns, and the amount of space on your roof and the quality of your roof are all factors that need to be considered. You’ll want to install a solar electric system in a location that is free from shading, ideally on a roof with plenty of southern or western exposure to the sun.
Luminalt will take these factors into consideration when providing you with a proposal of a system size, the system’s estimated performance, installation cost and return on investment.
Shading can have a significant impact on your system’s production. A fairly small amount of shade can affect the production of the cells within that shaded panel (similar to how a kink in a hose slows down the flow through the rest of the hose). Ideally, you should have unobstructed sun from 9am to 3pm.
Although all warranties are different, most solar panels are guaranteed to produce electricity for a minimum of 25 years. A well-constructed system may produce electricity for considerably longer.
The life of your roof is a consideration. If your roof is getting towards the end of its life, consider reroofing.
A good time to get quotes for a solar system is when you are looking to reroof. Your solar installer and roofer can work together to waterproof the solar mounting points on your roof so they are included with your roof warranty.
Why does it matter when I use most of my energy?
When you go solar, you must go on a time of use (TOU) rate schedule. PG&E offers TOU rates for which it charges more for electricity during peak hours on weekday afternoons, and less for electricity during off-peak hours. When you are on a TOU rate, the electricity your solar system generates and feeds into the grid during peak times receives a credit at the higher rates. If you use most of your electricity during off-peak hours, you then draw against those credits at the lower rates, allowing you to use more electricity than your system generated because you are using it at times when the rates are cheaper. Investigate different rate schedules to determine which is best for you. A solar contractor can help you determine which rate schedule is best for your electricity usage patterns, and which can provide the best return on investment for your solar system.
A solar electric system tied to the electrical grid feeds electricity into the grid when the system generates more electricity than you use and draws electricity from the grid other times when you are using more electricity than your system is producing, such as after dark. The clean electricity your solar system generates first powers your home and then sends excess electricity back to the grid. PG&E customers receive a retail-priced credit for the excess electricity their systems produces, which you can apply to your electricity bill. This is called “net energy metering” or NEM. If your utility is a municipality or you are part of a CCA group, the rules may be different.
We ask you to provide interval data information through Utility API. Utility API is a service that provides the data directly. Alternatively, you can download Green Button directly from your online PG&E account. Interval data provides us with data that is detailed enough for us to compare your specific usage patterns against the estimated electricity generation of a solar system designed for your home. Interval data allows us to analyze different TOU rates to find the best fit and return on investment for you.
How am I billed when I have solar?
When you have a solar system, your electrical use is calculated over a 12- month billing cycle called a “true-up period”. The electricity credits you earn by feeding the grid and the electricity debits you incur by pulling electricity off of the grid are tracked and applied month to month. At the end of the 12-month period you’ll get a True-Up statement, which in essence calculates the difference. If you used more power than you produced over the year, you’ll be billed for the overage. If you used less than you produced, your balance will be zero. Credits do not roll over year to year. PG&E also charges a monthly fee for you to be tied to the grid.
For many of us in PG&E territory, we also belong to a Community Choice Aggregation, or CCA.
In San Francisco, it’s CleanPowerSF. In much of the East Bay, it’s East Bay Community Energy. In the North Bay, it’s Marin Clean Energy.
CCAs manage the generation portion of electricity, while PG&E manages distribution and billing. In a nutshell,
Generally, CCAs provide better retail credit pricing for solar generation, however, if you have not built enough credits to offset usage, CCAs will bill you monthly for net usage overage, rather than through an annual True-Up bill.
Solar Electric System Basics
How does a solar electric (photovoltaic) system work?
Solar photovoltaics (PV) panels convert sunlight into electricity. An inverter converts the direct current (DC) electricity into alternating current (AC) electricity, the form of electricity our appliances use. This electricity feeds your electrical panel and excess electricity goes through your meter to the grid.
For more information on how solar panels convert sunlight into electricity see, Solar Photovoltaic Technology Basics at the National Renewable Energy Laboratory (NREL) link here.
How are solar panels installed?
The installation process is straightforward. The universal components are the panels, inverters, mounting points and a racking system to which the panels are attached, electrical pipe called conduit. Attachment method and racking varies by roof type. Each installation is unique. A general overview of the components are below.
On the roof:
- Posts called stanchions or solar mounting points are lag-bolted into your roof’s supports beams (flashings and sealants are used to protect any roof penetrations). If you have a standing seam metal roof, attachments are non-penetrating.
- Racking is attached to the stanchions.
- Solar panels are bolted onto the racking.
- Panels are wired together and that wire is fished through a conduit pipe down to your electrical panel and meter.
How long will installation take and do I have to be home?
A typical residential installation takes 2-5 days and you do not necessarily need to be home. The installation crew needs access to your roof, electrical panel and meter.
How big of a system do I need?
That depends on how much electricity you use, how much electricity you plan to use in the future, and what your motivations for going solar are. If you are considering an electric vehicle, talk with us about estimating your future usage based on how much you plan to drive. We can provide you with different options and layouts.
How long will my system last?
A well-constructed solar system built with quality components will last decades. Nearly all solar panels are guaranteed to produce for a minimum of 25 years, and today, most solar panels have microinverters, which also have a 25 year minimum warranty as well.
The Benefits of Going Solar
Vote Solar, a non-profit solar advocacy organization, wrote in June 2014 the GoSolarSF Progress Report: Economic and Environmental Benefits of San Francisco’s Solar Program. It contains great information about the benefits of going solar for both you and your community.
Does my Solar Installer matter?
Yes. Online solar contractor locators are often lead generators that sell your information to multiple solar installers.
Pick several installers and give them a call. Ask about their experience and their approach from initial site visit through installation and post-install customer care. The California Public Utility Commission recommends receiving three bids from separate contractors before signing a contract. You will learn a lot in this selection process.
Experience is key when it comes to choosing a solar installer. Here are some good questions to ask as you evaluate companies:
How many local installations has the installer done?
Have you seen photos of their work? Select an installer with proven experience and documentation. There are definite differences in the overall aesthetic quality and performance of installations. You will be looking at your system for many years, it is important that you like how it looks.
Does the company provide references from previous customers?
Ask for a contact list of previous customers to find out about customer satisfaction. Make sure to ask for a customer that has been installed for a number of years. If you contact the customer, ask them if the company was courteous, professional, on time, and responsive. Ask to speak with a client that had post-installation concerns about their system. Was the company responsive to any issues that arose after the installation?
Will they do the work themselves, or will it be done by subcontractors?
Many companies sell and finance solar systems, but do not install them. Ask the company if their staff will install the system, or if they subcontract the installation of the solar systems they sell.
What are their quality control practices? What are their warranty and post-installation service policies?
The GoSolarSF incentive program requires a solar system to be warranted for ten years, but this should be considered the bare minimum. SunPower systems, which Luminalt offers, have a 25-year warranty that is considered an industry best practice.
Are they licensed and bonded in the state of California?
A qualified solar company should carry C-46 (Solar), C-10 (Electrical) and B California contractor licenses. You can look at a company’s licenses on the CSLB website.
How experienced is everyone on the crew?
Will your specific installation team be certified by the North American Board of Clean Energy Professionals? NABCEP-certified installers have met all experience requirements, have passed a rigorous exam and must maintain continuing education credits to remain certified. Individuals,not companies, hold this certification.
Do they have a code of ethics?
How quickly can the company install my system?
If you are ready to start soon, make sure the company can meet your expectations. Generally, a healthy backlog of projects can be an indication that a company is successful and has a good reputation for providing quality installation and care.
Choosing Between Competing Bids
Deciding between multiple bids is not as simple as choosing the lowest bid. The lowest bid can mean low quality installation or materials. Ask to see performance estimates for the system, from installation to end-of-life. Ask to see what equipment has been specified in the bid. Ask the installer what materials they will use to waterproof the roof penetrations.
Does the proposal list your system size in AC or DC kilowatts?
Solar electric panels produce DC (direct current) electricity but your home appliances use AC (alternating current) electricity. As electrical energy is changed from DC to AC in the inverter, there is some loss. A contractor that lists your system size in only DC kilowatts is simply adding up the wattage of all the panels, rather than giving you an estimate of actual production. Rebates, such as the GoSolarSF program, usually base incentive amounts based upon AC system size.
Does each proposal give estimated production based on the same number of sun hours per day?
Make sure that the estimated production (in kilowatt hours per year) on each proposal is based on the same number of sun hours per day. Because actual energy production depends on the amount of sunlight (based on latitude and local weather conditions), a solar contractor can use a higher figure of sun hours per day to make their proposed system look like it will produce more power than it actually will. San Francisco receives about 5.5 peak sun hours per day.
Do you feel comfortable with the installer?
Does the contractor have a philosophy and approach that corresponds with yours? Personal attention and responsiveness are important. If you find that one solar contractor seems to communicate more clearly and is more responsive than others, take this into consideration when making your choice.