Frequently Asked Questions

What is 'PV'?

PV stands for Photovoltaic. It is a solar energy technology that uses unique properties of semiconductors to directly convert solar radiation into electricity.

How much does it cost?

In California and 5 other states, we surpassed "Parity" in 2012, meaning it is less expensive to produce electricity than it is to purchase electricity from the utility, even excluding incentives. But there are still great incentives available, like a 30% Federal Tax Credit available through 2016.

Can I finance the purchase?

Solar Loans are available from banks and credit unions like Admirals Bank, San Diego Metropolitan Credit Union, Matadors Community Credit Union, from 5 to 20 year terms, from 4.99-8%, depending on credit score. Some "Solar Loan" options have an acquisition fee of 3%.

What is Solar Electrical Energy?

Solar photovoltaic (PV) is also called Solar Electrical Energy. Both are generally interchangeable terms. Solar electric systems utilize sunlight to create electricity.

What is Solar Hot water system?

A solar hot water system is equipment that heats potable water using sunlight. These systems do not produce harmful greenhouse gases and hence are considered a green form of energy. Uses include domestic & commercial hot water, heating pools etc.

What is a Solar/PV module?

A solar module is a PV device consisting of a number of individual cells (usually 60 or 72) connected electrically, laminated, encapsulated, and packaged into a frame.

What is a Solar panel?

A solar panel is an array of two or more solar modules framed or joined together. Sometimes, individual modules are also referred to as a solar panel.

What are the different technologies of solar modules in order of efficiency?

Mono-crystalline modules are most efficient and the most expensive. Poly-crystalline modules efficiency is less efficient, but cost less as well. Thin film solar modules are the lowest efficiency and also the cheapest.

What are the various types of Inverters?

Micro inverters and string inverters

When is a string inverter used?

String inverters are generally used for small to medium sized residential or commercial PV systems. General system size ranges from 2kW to 100kW. Multiple string inverters are used for systems larger than 100kW going to 500kW range. It is usually a design criterion and there is no fixed rule of thumb.

When are micro inverters used?

Micro inverters are small inverters that go one each per solar module. These are usually used for residential or small commercial systems. They perform very well in a PV system installed on different roof levels, pitch and where there is possibility of little shadowing at certain periods during the day. Currently Enphase is the only manufacturer of micro-inverters.

How long does a solar module last?

Most industry standard solar modules come with a 25 year linear power output warranty and a 10 year product warranty on materials and workmanship. Generally, when not damaged by external factors, good quality modules outlast the 25 year period.

What is linear power output warranty?

As like any equipment, aging also affects solar modules and cells. Output power efficiency linearly decreases over time. Current industry warranties for good quality modules is about 90% efficiency after 10 years which linearly decreases to about 80% at 25 years. But the modules still continue to produce power beyond 25 years.

How long does a solar electric system last?

A solar electric system usually lasts 25 years and beyond. If undamaged and maintained properly, solar modules extend beyond 25 years. String inverters generally carry a initial 10 year warranty and may have to be replaced after 10 to 15 years. Micro inverters have warranties up to 25 years. Good quality inverters have a longer warranty and extended life. Racking and mounting mechanical system typically has a 20 to 25 years warranty. It is important to chose good quality longer lasting components and also look for available extended warranties if affordable.

What are the warranties on the solar electric system?

Solar modules - 25 year linear power output warranty and a 10 year product warranty on materials and workmanship. Inverters - 10 to 15 years with available extended warranties. Some manufacturers offer up to 25 years. Racking and mounting systems - generally between 10 to 25 years. Labor & Workmanship warranty - general industry standard is 10 years.

What kind of maintenance do Solar Panels require?

Solar panels generally require very little maintenance since there are essentially no moving parts. A few times a year, the panels should be inspected for any dirt (soiling) or debris that may collect on them. Most of the time, rain cleans them off. To clean, simply use a standard garden hose to wash the face of the panels either early in the morning or in the evening. Avoid spraying cold water onto hot panels or you could risk cracking them, since uneven thermal shock could theoretically break the glass.

Does my solar installation increase my home insurance?

  1. All installation (roofing and electrical) work will be done by licensed professionals with proper county and state approvals.
  2. Equipment will carry UL certifications, where applicable. All this does not add any risk to your home and thus home insurance in most of the cases does not get affected at all, although the system does contribute to an increase the home/property value.

How will it affect the value of my house?

According to several studies the value of a house, as well as resale value, increases with installation of a solar energy system.

Does my solar installation increase my property taxes?

No.

If I move, can I take my solar electric system?

Although you can take your solar electric system with you if you move, it usually is better to leave it on the original house because it increases the resale value of a home. Some incentives and rebate programs may not allow a system owner to remove the system within an initial period of time. Please call us or check with your rebate program office.

How do I know if my system is producing what it is supposed to?

Many PV systems these days come with data logging, monitoring and reporting systems. This will allow you to see how much energy the PV system is producing daily, weekly, monthly and annually. System owners can see this data locally on-site or from a remote location provided the monitoring system is connected to the internet. These systems continuously monitor the health and performance of the PV system, continuously collect all the data from the inverters on the system side, thereby keeping you informed of the system's status at any given time. In case of the event "Error", they also have features that inform you immediately by e-mail or text message. Remote diagnosis is also possible. An internet connection is required to use all these features.

What is net-metering?

Net-metering is an important and interesting concept. A Net-meter is a special type of electrical meter that spins (moves) both forward and reverse. When your PV system is producing a lot of electricity during the day and if your appliances or electrical loads are not using all of it, the excess electricity is exported to the utility grid (goes from your PV system to the electric utility pole or underground junction). The net-meter in this condition moves reverse. During early mornings, evenings, nights or at any time when there is not enough sunlight for your PV system to meet electricity demand, your appliances and electrical loads use power from the utility grid (import). The net-meter is this condition moves forward. Generally, the utility company calculates the difference between energy imported versus exported each month and bills the customer. If you have a sufficiently large PV system that produces 100% of your energy needs, your electric bill can be zeroed out, except for some account maintenance charges.

Why is net-metering important?

Because solar energy is an intermittent resource you may not be using the power when it is generated, and net-metering allows you to receive full value for the electricity you produce without installing and investing in a battery storage system.

How do I determine what size of system I need?

The size of your solar electric system depends on how much electricity you use. Two homes the exact same physical size may use different amounts of electricity and therefore require different size systems. Major electrical loads in a home are air conditioners, electric heaters, other heating element appliances, motors and energy use habits of the occupants. Generally, the total number of kilowatt-hours used in the last 12 months is used to estimate the system size you would need to meet your annual electrical energy needs. Sometimes a slightly over-sized system is installed to allow for the possibility of a growing family, immediate future electrical loads or other factors that may play a part. When a solar system produces more electricity than consumed, the unused portion is fed back into the utility grid and will actually be credited back to your utility account in a program called net-metering. In some states, an over-sized system without justification and approval may not be eligible for some types of grants, credits or incentives.

What factors determine the size of the system I can install?

Primarily the roof size and structure, orientation of the property, un-shaded roof or land sites, energy requirement, budget etc.

What happens when I need to re-roof?

In most situations, the systems can be easily removed and reinstalled. For a nominal cost, systems can be installed, then re-installed once the re-roofing is completed. If the roof is a tar and gravel design, it may be possible to simply tilt the panels up and re-tar and gravel.

Does my solar system produce power on a cloudy day, rainy day, foggy day?

Yes, a solar module does produce power even on such days, but less. Production directly depends on the intensity of sunlight, also called irradiance.

Contact Us with any questions you may have about Wipomo.