32 Years In Business. 21,000+ Solar Systems Installed. One Local Company. Diablo Solar.

Frequently Asked Questions

Solar Electric

How do I maintain my solar PV system?
Maintenance required to keep your solar electric power system in working order is very minimal. With very few moving parts and with solid-state electronics, your photovoltaic (PV) system is designed to work day-in and day-out for 30 to 40 years. Washing the modules if/when they get dirty, and clearing out any debris that may collect underneath them, are the only maintenance tasks the homeowner has to worry about. Simply spray them off occasionally with a garden hose and they will continue to produce power for decades to come!
Loans, Leasing and Ways to Go Solar

Diablo Solar has partnered with Provident Credit Union to provide low interest rate unsecured solar loans. Provident is ready to help with special financing that will enable you to use natural resources responsibly and economically. The Solar Advantage Loan is a fixed rate loan for financing the purchase and installation of solar power for your home. Once installed, a solar power system requires little or no maintenance and will provide electricity cleanly and quietly for years to come. Saving green while going green — it's a win-win scenario!

Here's how you can go solar and save: Sunpower Solar Financing

  • A fixed rate of 6.5% APR ²
  • 20 year term (240 months)
  • Borrow up to $35,000
  • Unsecured Loan — No Home Equity Required
  • Minimum Credit Score of 680 Required
  • $7.46 payment per $1,000 borrowed
  • Decision in less than 24 hours
» For a detailed estimate & free consultation with a photovoltaic specialist, call 925-313-0600 today.
How much will my system cost?

Installed system pricing is highly site specific. Some of the factors that determine price include:

  • Size of electric bill (and amount you want to offset)
  • Location of your home
  • Shape, height and slope (pitch) of roof
  • Roof accessibility
  • Existing electrical service, sub-panel and electrical equipment
  • State and local incentives that may apply, in addition to the 30% federal investment tax credit.

In general, the cost is about $4,000 - $7,000 per kW ($4-$7 per watt). A 2,500 square-foot home with moderate electricity usage (an electric bill of about $175 per month) could require a 4kW system. This would cost about $18,000 to $22,000 before state and federal rebates and approximately $12,000 to $16,000 after rebates.

What solar PV modules and inverters does Diablo Solar install?

Diablo Solar is one of the East Bay’s leading installers of American-made Suniva PV Modules (solar panels).

Located in Norcross, Georgia, Suniva is an offshoot of Georgia-Tech University and is the leading American manufacturer of high-efficiency, cost-competitive PV solar cells and modules. The company is known worldwide for its high-quality solar products, patented low-cost manufacturing technology, and long-term reliable performance. Their ground-breaking manufacturing process ensures the combination of high power and exceptional value in every product they make, while their research milestones continue to set the standard in the global PV marketplace.

Diablo Solar currently offers the Suniva Optimus line of high-powered PV Modules:

  • Solar cells made in the USA
  • All-Black streamlined look:  black cells, black backsheet and black frame that blend seamlessly into your roof
  • High Power - up to 19% cell efficiency
  • 25-Year Power Production Warranty
  • 60-cell - 39 inches x 65 inches (17.4 sqft)

Inverters for Solar Electric PV SystemInverters

Diablo Solar uses inverters from Enphase (micro-inverters), SMA (central-stringed inverters) and SolarEdge (Power Optimizers). With warranties ranging from 10 to 25 years, and efficiencies up to 98%, we only install the highest quality inverter options.

SMA: SMA SB 5000-8000 US   |    SB 3000TL-6000TL
Enphase: M215   |    M250
SolarEdge: SE 300-11400 Inverters   |    SE Power Optimizers

In addition to Suniva, Enphase, SMA and SolarEdge, Diablo Solar has access to many other types of modules and inverters including SunPower, SunPreme, Mitsubishi, Sanyo, Xantrex, Fronius, SunTech, Trina, Yingli, Canadian, Solar World, ET Solar, LG Electronics, Phono, Bosh-Aleo and Winaico. If you have a particular product in mind, feel free to ask a Diablo Solar photovoltaic (PV) specialist.

Will a photovoltaic (PV) solar-electric system save me money?

Yes! Continually rising electric costs coupled with the 30 to 40 year life expectancies of the solar modules (power output warranty is 25 years), systems are expected to pay for themselves in as little as 5 to 8 years. Many Diablo Solar customers are expecting hundreds of thousands of dollars in total savings over the guaranteed, warranty life of the modules. In fact, many customers find themselves “cash-positive” the first month after a solar purchase. This simply means that their new, lower electric bill added to their finance charge with their lender is less then their old electric bill. More money in your pocket while helping the environment — a winning combination!

Solar Electric PV systems also add value to your home. A recent study of over 72,000 home sales by the Lawrence Berkeley National Laboratory concluded that the “average premium for existing homes with PV (is) more than $6 per watt,” or about 90% to 110% of today’s average PV installation cost. You can also maximize your return and add more value when you combine energy efficiency features with your solar system.

Your solar system will hedge against rising energy costs for as long as you own your solar-powered home. Your roof will become a mini power plant, producing energy for a fraction of the cost of your current utilities.

What rebates and tax credits are currently available?

The California/CSI solar rebate program has ended, but there is still a 30% Federal Tax Credit that is applied to your Federal Income Tax bill. This tax credit covers 30% of your total out-of-pocket cost. This is a tax credit, not a deduction, so usually income or tax bracket is not applicable. You simply subtract the tax credit from the tax you owe or add the tax credit to your tax refund. Most get the full 30%. Not everybody qualifies for this tax credit (about 99% do), so Diablo Solar requests that you talk to your CPA or qualified and licensed tax consultant before going forward with a solar purchase. Diablo Solar clients do pay this portion of their solar cost at the time of installation, and the tax credit is applied to your Federal Income Tax bill.

For example, a system with a gross cost of $25,000 would actually cost:
Gross Cost $25,000
Tax Credit ($7,500)
Net/Final Cost $17,500

Total Savings 30%

While this is a common scenario for most purchased systems, Diablo Solar also offers $0 Down solar options as well. Your system will be installed for free, and you will simply pay a low monthly solar payment, guaranteed to be less than your existing PG&E bill. In these situations, nothing is paid at the time of installation, and the tax credit is covered by Diablo Solar until after the following tax season.

Where are solar electric power systems typically installed?

At Diablo Solar, we typically install solar-electric modules on the south-facing roof of your home. We can install them on a patio cover, pergola or trellis and we have the ability to build a structure on the ground or on the side of a hill as well.

South is always the best direction for solar in our area, because the panels are exposed to the most hours of direct sunlight per day. East and West-facing roofs are also usable, although not as desirable. In most cases, north roofs are not used for solar. It is important to note that solar-electric systems should not be installed in areas where they might be significantly shaded during the day.

Am I still connected to PG&E or another utility electric company?

You will continue to rely on PG&E as your local utility electric company. If you are a PG&E gas customer, you will continue to receive your monthly gas bill. A solar-electric system does not impact your gas usage. You will also remain an electric customer with PG&E, albeit now on a year-to-year basis. As a solar-electric customer, you will no longer get a monthly electric usage bill (you still get billed monthly for some basic PG&E fees, about $12 per month). You will get billed for your consumed (used) power once per year, on the anniversary of your solar-electric interconnection. You still have the option of paying for your usage month to month, but PG&E does not require payment until the end of your anniversary year (referred to as your “true-up” period).

For example, at night or on a very dark or rainy day, your solar-electric system may produce very little power, so PG&E will continue to sell you power, just as they do currently. On a bright sunny day, however, you might actually produce more power than you consume. In this case, PG&E will also act as your battery, storing your surplus power when you don’t need it, keeping it for you until you do. They will actually buy back your surplus power at the same rate that they would sell it to you in the form of a credit. You will continue to buy and sell credits freely until the end of your true-up period, when you settle up your bill. If you have used more power than you have produced (very common in most cases), you will owe them the difference. If you produce more power than you actually use, PG&E will give you the option of applying that surplus to your gas bill or next year’s electric bill, or they will issue you a check for that surplus power at a wholesale kWh rate.

How does a Solar PV System Work

The modules we use are a monocrystalline silicate that, when exposed to the sun’s light energy, produce electricity in the form of Direct Current (DC) power. DC electricity is what powers your car’s electronics or many other small electronic devices like cell phones or MP3 players. Your home consumes Alternating Current (AC) power, so the power generated by the solar modules has to first run through an Inverter, converting the DC power to AC. The electricity is then connected to your home through a circuit breaker in your existing electrical panel. This is an “add-on” system: you use your solar generated electricity through your homes current wiring and outlets.

Solar Pool Heating

How about maintenance?

No special periodic maintenance is needed. If you close your pool at the end of the season the solar system will automatically drain down if you have followed the installation instructions. However, we highly recommend our Shutdown/Startup Service in the Fall and Spring. This cost-effective service is a smart way to keep your solar heating system in top shape by allowing a Diablo Solar professional to not only properly start-up and shut-down your system, but also to inspect it and catch any problems early on.

How efficiently will solar heat my pool?

If you follow our recommended solar heater sizes and have proper exposure to the sun, your pool should be ten to fifteen degrees warmer than it was before you heated it, under the same weather conditions. Evaporation of water from the surface of the pool causes most of the cooling of the water. The larger the solar collector area, the more of the sun’s energy it will collect and send to the pool. Therefore, the larger the solar collector area is in relation to the surface area of the pool, the warmer the pool water will be. If in the future you decide you want an even warmer pool or you would like a longer pool season, you can add solar collectors to your FAFCO system.

How Does a Solar Pool Heating System Work?

A typical FAFCO system consists of solar collectors, easily mounted on your roof, and an optional solar sensor and automatic control unit. You simply set the automatic control unit for the desired water temperature.

Solar pool heating Pleasanton Sensors detect changes in the water temperature and direct the automatic control unit to close the control valve so as to route water through the solar heat exchangers. Warm, solar-heated water flows back to the pool, continuously circulating through the collectors until it reaches pre-set temperature levels.

When the sensors detect that the water entering the collectors is already the desired temperature, the control unit causes the valve to open and water then bypasses the solar system and goes directly back into your pool from the filtration system.

Service and Maintenance

Do you have to clean solar electric panels?

Your solar electric panels should be cleaned and inspected at least once per year to maximize the electrical output performance and insure the system is on and working as designed.

Do we have to remove the solar panels when we get a new roof?

Yes!! All of the solar panels and piping will have to be removed and then reinstalled once the new roof has been completed. Diablo Solar can provide you with a free cost estimate for the removal and reinstallation and will coordinate all scheduling with your roofer directly. If you do not have a roofer and need a referral Diablo Solar can provide you with multiple roofing companies that we work with on a regular basis and would recommend.

How do I turn my solar system off in case there is an emergency?

Depending on your situation, you will need to go out to where your pool equipment is located, then turn off all of the pool equipment at the control panel. If you do not know how to work the control panel, go to the sub-panel and shut off all of the breakers to the pool. Call Diablo Solar to setup a service appointment.

Sometimes I hear water dripping in the gutter in the morning, are my solar panels leaking?

If you only hear or see water in the mornings it is more than likely just condensation on the Solar panels that is running off into the gutters. If you continue to see water throughout the day you may have a leak and should have us come out and check it.

My pool guy told me to call you because the vacuum relief valve on the solar panels is sucking in air. Do I need the Vacuum Relief Valve?

YES!!  A Vacuum Relief Valve must be installed on every pool solar system. The sole purpose of the VR valve is to open up and suck in air allowing the water to drain down without damaging the panels and piping.

How long is the warranty on my new FAFCO solar pool panels?

FAFCO solar pool heating panels have a full twelve year warranty from the manufacturer including labor.

There is a loud noise coming from my roof when the solar shuts off, should I call 911?

No need to call 911, it is most likely the Vacuum Relief Valve on the solar panels doing its job sucking in air in to allow the panels to drain.

How long do I need to run my solar system in order to get maximum heat in the pool?

You should run the solar system for a longer period of time during the beginning and end of the season to get as much of the suns heat into your pool. During the middle of the summer when everything is hot you can, shorten your run times to accommodate your usage.

I have a brand new variable speed pump and run it on the slowest speed, now my solar is not working?

The solar panels are designed for approximately 3-5 GPM (gallons per minute), per panel and will not work on low speed. The speed of the pump will need to be increased.

Why are there air bubbles coming out of the inlets into my pool when the solar is on?

The first thing you will want to check is your filter to make sure it is clean.  A dirty filter will slow down the flow of water, not allowing enough water to go up to the solar panels. This will cause the vacuum relief valve on the solar system to suck air into the system and put air bubbles back into the pool.

Do the solar pool panels need to be drained in the winter?

YES!!  All solar pool panels need to be drained of all water during the cold winter months in order to protect them from FREEZE DAMAGE.  Diablo Solar can provide this service for you if you are not comfortable with going on the roof and doing it yourself.