Solar FAQs

Technology

How does a solar electric system work?

A solar electric system (also known as a photovoltaic system) uses solar panels installed on your roof to convert sunlight to electricity. This electricity is then converted to AC power which you can use to supply part of your electric use.

Are solar electric systems reliable?

Solar electric systems have been in operation for many years. The first commercial application of solar electric power was in the Aerospace industry. In the early 1950s, the aerospace industry was already using solar cells to extend the useful life of satellites. Currently, there are over 1500 solar electric systems installed in the SMUD service territory. These systems account for more than 13 Mw of energy.

How long will the solar electric system last?

Most new solar electric systems have a 20 year warranty. The average system degrades in output by approximately 1% per year. Example: In 20 years, a 100 watt system will produce at least 80 watts of electricity.

Will my rooftop solar panels heat my pool or the water in my home water heater?

No. The technology used to convert sunlight into electricity is different from the technology used to heat water. Hot water and pool heaters use a technology called solar thermal. The two technologies very different, and have no common parts.

Maintenance and Repairs

Do I need to do any maintenance?

There is very little maintenance with a solar electric system. Washing the panels a couple of times a year can increase the output of the system. Washing can be done with a regular water hose and should be done early in the morning before the panels get hot. Caution: Spraying cold water on hot solar panels can cause damage that cannot be repaired.

Who is responsible for repairs, and what happens when the system breaks down?

SMUD’s PV Incentive Program requires contractors to provide a 10-year warranty. After the warranty expires, you will be responsible for finding a contractor to repair your system. Visit smud.org for a current listing of solar contractors.

How do I know if the solar contractor is good?

The companies on SMUD’s PV Contractor list are licensed to install solar with the California State License Board and provided evidence they are experienced installing solar. SMUD recommends you cross check these contractors with the Better Business Bureau (BBB) and check all references.

Does having solar on my roof means I am “off the grid” and not connected to electricity from SMUD?

No. Having solar on your roof does not mean you are “off the grid”. While it is possible to design a system to produce all of your power and enable your home to be “off the grid,” SMUD does not recommend that you install a system that large. A solar electric system produces only 3% of its yearly power in December. Therefore, you would need a very large system to produce enough power for your December usage. Conversely, such a large system would not be needed in June, when the system produces 13% of its yearly totals. To effectively go “off the grid”, a home would require massive battery banks, which can add 40% or more to the cost of the system, and ultra-low energy consumption appliances and lighting should be incorporated into the dwelling. To convert a conventional home to an “off the grid” home can be done, but it is very expensive.

What happens with my solar electric system when I move? Does it stay with the house or can I remove and re-install it on my next house?

Most solar electric systems are attached to the home’s roof and are part of the home. The cost to remove and reinstall the system is usually offset by the greater resale value of a home that produces some of it own electricity.

What happens at night when the sun is down? Do I still get electricity? Does electricity get stored somewhere in my house?

At night, or on very stormy days, a conventional solar electric system goes dormant. During these dormant times, you are consuming power from the grid. When the sun comes back out you are producing energy. If your home does not consume all of the electricity that you are producing at that moment, the excess gets sent back to the gird. You are credited this amount on your bill. This process is called net metering

Site and Product Selection

How can I tell if my house will be a good fit for solar?

The typical home will need to have a southern-facing roof with little or no shade. East and West facing roofs also are viable but the yearly output is decreased by 13% or more over the course of the year. A perfect slope for your roof would be 25% to 30%. While a solar electric system will produce power at a wide variety of slopes and orientations, it is important to try to maximize your output in relation to the size of the array.

How much roof space do I need?

The newer solar electric systems produce approximately 10 watts per square foot. An average system would require 200 to 300 square feet for a shade free southern-facing roof.

What type of roof do I need?

Solar manufacturers have created mounting methods and equipment for most commonly used roofing material.

What manufacturer is the best?

SMUD does not recommend nor endorse any manufacturer. We offer rebates only for products listed on the State of California energy commission website. www.gosolarcalifornia.org/equipment. These products have been tested and approved by industry standard testing procedures.

What installer is the best?

While SMUD does maintain a list of contractors, we do not recommend any specific installer. SMUD recommends talking to several contractors during the process and checking all available references.

How can I calculate what size solar system I need?

The size of each system should be based upon your electricity use patterns and not the size of the roof. Customers with large electric bills may consider a larger system. A good rule of thumb is to start at a 2000 watt system and determine the impact to your bill before you increase the size of the system. A 1,000 watt system will produce about 1,500 kWh (kilowatt-hours) per year.

First, total all of your Tier 3 electricity use for the last 12 months and divide by 1,500. This will give you a system size that will keep you out of the highest energy cost. There are online bill calculators that can help. Many contractors can do this for you if you provide them with 12 months or more of bills. For more information, visit the solar estimator on smud.org.

Besides the basic warranty, price & service questions, what are the other questions I should ask?

Always try to get an idea what is going to be produced by the system. While it is impossible to predict the weather and its impact on the output of your system, there are formulas to determine expected output.

Will installing solar create any dangerous areas on my roof or in my house?

Any electrical device can be dangerous if opened or tampered with in any way. All products used in SMUD solar arrays are required to be UL listed and installed in a safe, code compliant manner. However, most systems are located on the roof and therefore out the danger from tampering.

Who actually owns the system?

Most systems are owned by the homeowner but a few leased systems have been installed in the last year.

Will my roof leak?

Over the past 20 years, SMUD has installed hundreds of systems with very few leaks. The newer mounting systems are even more resistant to leaks. Ask your contractor about how the system array will be mounted and how it will be sealed.

Can I put it someplace else on my property other than my roof?

Yes, many people with larger lots or acreage are placing the solar electric system in areas that maximize the sunlight. A rooftop installation can be less expensive, but prices are becoming more competitive for on ground-mounted arrays

How long does installation take?

System size, product availability, and location can impact the installation time dramatically. A normal 2000 watt system can generally be installed in 1 to 2 days. Permitting, design and product ordering can add a month or more to the process.

Do I have to re-roof my entire home?

In many cases not, but it depends upon your roof’s condition. The solar electric system will be on your roof for at least 20 years, so the roof should be able to at least last that long.

I am buying a new home, they have an option for solar. Should I buy the solar?

Purchasing the solar when you buy a new home can be one of the most cost effective ways to invest in solar. The cost that solar would add to your mortgage payment is almost always less than the savings you would get on your SMUD bill. Many SMUD SolarSmart homeowners have a very small electric bill.

Does SMUD require a building permit if I install my own system?

Yes. SMUD requires a building permit for all installations whether installed by homeowner or contractor.

I am re-roofing my house, should/can I install integrated solar tiles?

Integrated solar tiles that are designed to integrate with concrete tile are used primarily in new construction application. While they can be used in a retrofit or re-roof installation, the cost associated with the conversion to tile roof generally prohibits installation of this type of system.

Costs

Will a rooftop solar electric system lower my bill?

Yes, solar electricity lowers your bill, but you must still factor in the upfront cost of the system.

Who benefits most from solar power?

The most cost-effective installations are in homes with very large electric bills. However, SMUD has found that many people are installing solar for the environmental benefits. While the payback is faster for customers who have larger bills, many customers are happy just being part of the solution to save energy.

What is net metering and how does it work?

Net metering is a billing method that allows you to receive credit for each excess kilowatt hour of electricity your solar electric system produces. SMUD rolls back your meter if you produce more energy than you use. When your house uses power from your solar electric system, you are not buying power from SMUD, therefore lowering your bill.

I have rental homes. Can I put solar on those homes and have it apply to my house?

No. Net metering is only available for the location at which the solar electric system is installed.

Do I get money back if I make more electricity than I use?

Yes. While the net metering law does not require utilities to pay retail for excess generation, SMUD’s current policy is to pay retail for any properly sized residential system.

What do you mean “properly sized” system?

SMUD will neither rebate nor provide incentives for any system larger than your current home’s load. If you consume 10,000 kWh per year, SMUD will rebate a system that produces no more than 10,000 kWh.

Are there any tax credits available?

A potential buyer should always contact their tax consultant before making a decision, but at the time of this writing, a federal tax credit of 30% is available. Your tax consultant would help you determine if you qualify.

Does SMUD finance the system?

Yes. SMUD currently has 10 and 20 year financing options available.

What does it cost?

Systems price vary wide by system size and technology. The most expensive systems are ones that integrate with concrete tile roofs. The least expensive are traditional framed modules which are mounted on the roof. Average prices in the SMUD service area are $8-$11 per watt. This price is before the tax credit or any SMUD rebates.

How long does it take to pay off?

The payback time is determined by many factors, most importantly the amount of your current electric bill. Some customers with lower bill amounts have a 20-plus year payback period. Customers who have much larger bills take as little as 7 to 10 years to see a return on their investment.

Does SMUD sell solar electric systems?

SMUD does not sell solar electric systems directly to customers. SMUD’s solar program offers rebates to customers to buy down the cost of their system.

What is the rebate?

Click here for the current rebate.

How do I apply?

If you are buying a system from a contractor on the SMUD list, the contractor will take care of the paperwork. If you are installing the system yourself, you can download the forms and the handbook at http://smud.powerclerk.com

I have existing solar. Can I install more and do I get the same rebates?

You can install more solar on an existing structure but that system will only qualify for the current rebate amount.

Finding a contractor

How do I find a contractor?

Download SMUD’s solar contractor list and talk to as many contractors as possible. The contractor you select will place a rebate reservation with SMUD. This will start the SMUD inspection procedure. Many contractors on the SMUD list also offer SMUD financing.

How can SMUD help me in the solar purchasing process?

SMUD provides information to assist you but no direct recommendations or assistance. Many future solar customers take SMUD’s homeowners class at our Energy & Technology Center at 6501 S Street. Check www.smud.org for upcoming classes.

Do contractors need to be certified or licensed to install solar?

A contractor should have a C-10 electrician’s license or a C-46 solar installer s license. SMUD also recommends you use a NABCEP certified installer.

Does SMUD inspect the contractor’s work?

Yes. SMUD goes out to the home before the system is installed to verify the placement and shading of the system. After the building department has approved and completed the final inspection, SMUD returns for a final inspection.

Additional resources

California Energy Commission

800-555-7794

California Solar Energy Industries Association

800-225-7799