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Frequently Asked Questions

Important questions to ask a solar contractor:

Top Question No 1: Is the contractor a full‐time solar installer exclusively focused on solar PV?

LightWave Solar holds an unlimited TN electrical contractors license. We are 100% focused on turn‐key solar PV design and installation with over 30 full‐time employees.

Top Question No. 2: What is included in the contract amount?

LightWave Solar provides turn‐key design and installation.  This includes:

  • Site evaluation to verify system design requirements
  • Electrical drawings and site plans by in‐house engineers
  • Completion of interconnection application, TVA Green Power Providers Agreement, and all other interconnection paperwork required by  local utility
  • Permitting
  • Equipment procurement (panels, inverters, disconnects, meter, conduit, wire, etc. – everything needed for fully functional system)
  • Installation and inspections
  • Grid‐interconnection/commissioning with TVA and local utility
  • One‐year workmanship warranty

The questions we get asked the most about solar:

How does a solar electric system work?

Sunlight excites electrons in solar panels, and electricity flows to the inverter where it is converted from direct current (DC) to alternating current (AC). Most systems are connected to the grid through the local utility. For systems up to 50kW, local utilities partner with TVA’s Green Power Providers program to pay solar system owners the escalating retail rate for 100% of their solar electricity for 20 years.

What size system do I need?

System size is usually determined by available roof space and budget. We will measure your roof to verify space and shading. Another consideration is electric bill amount. Systems can eliminate electric costs or offset a significant portion. We can analyze your bills to determine the appropriate system size.

How much does solar cost?

The cost depends on the amount of suitable space for the panels, the system size, and the amount of money you want to invest in solar. A typical residential system costs $20,000-$30,000. This includes everything required to provide a fully installed, grid-tied system. Additional costs would be required for ground-mount systems, long distance ground work, concrete work, extended travel, AC modules or battery back up (battery systems start at $17,500).

What are the financing options?

Commercial solar projects
Our customers have obtained commercial solar loans through BB&T, First Farmers & Merchants, Pinnacle Financial Partners, Pathway Lending and more. In fact, BB&T partnered with LightWave Solar to provide customized financing options for commercial solar installations, including an attractive equipment loan with interest rates as low as 5% for qualified customers. Some customers obtain a loan for 70% of project costs and recoup the 30% federal tax credit to become cash flow positive in the first year. Contact LightWave Solar to discuss your project and goals.

Residential solar projects
We offer unique solar financing options that make solar energy more affordable for homeowners. Our $0 down loans have no interest and no payments for 12 months! This means you can receive your 30% federal tax credit and up to 12 months of electric bill savings before ever making a payment on your system. Contact us to get started.

What are the available incentives?

  • The 30% Federal Investment Tax Credit (ITC) is available for solar systems placed in service by 12/31/19. The credit amount is uncapped and equal to 30% of total system cost.
  • For businesses: Five-year Accelerated Depreciation, also known as Modified Accelerated Cost Recovery System (MACRS), is a method of depreciation in which a business’ investments in solar property are recovered (can total about 30% of total costs) over six years through annual deductions.
  • For systems up to 50kW, TVA’s Green Power Providers Program pays the escalating retail rate per kWh (currently about 10 cents) for all solar electricity production for 20 years. For example, a 10kW system generates about 1,080 kWh per month on average, so 10kW would generate about $108/month on average at current electric rates. This would appear as a credit on your monthly bill.
  • For systems over 50kW, we can determine if a “behind-the-meter” interconnection (outside of a TVA program) would benefit your business or organization.
  • For eligible rural businesses, USDA offers a 25% grant for solar systems. LightWave Solar has grant writers on staff, and our grant approval track record is 97%.

What steps should I take to decide if solar is right for me?

  • Gather your last 12 electric bills to determine your annual use (or we can request your bills from your electric company).
    Think about how much how much money you want to invest in solar.
  • Consider what site might be the best location. Solar performs best on south-facing roofs. East/west roofs with low pitch are also suitable. There should be little or no shading from trees, chimneys, and dormers. If the roof is not suitable, we can install panels on another structure or on the ground. We have shade analyzing tools that help determine the best location for solar panels.
  • Contact us to request a free preliminary estimate and see a sketch of the project on your property.

What happens during power outages?

A grid-tied solar system must shut down until utility power returns so that it doesn’t back-feed the grid. When grid power goes out, the inverter will automatically shut off. When the grid power is re-established, the inverter will automatically turn back on after it has synchronized with the utility grid.

Will my system work on cloudy days?

Usually, yes, but it will be less productive. Production is proportionate to the thickness of cloud cover.

How will I know if my system is producing what it should?

The inverter’s faceplate shows production data. You can compare your actual production to our estimates to ensure your system is on track. Production monitoring that can be accessed on-line is available at an additional cost.

How long does it take to install the system?

For a typical residential system, it takes about three days to install the PV panels and equipment.  Then, the system must pass a final State electrical inspection which normally takes one business day to schedule and pass. It can take another 7-10 business days for the utility to install the separate solar meter.  The local utility and LightWave Solar will turn on the system once the utility company has installed the solar meter.

What are the panel and inverter warranties?

The solar panels we install have a product warranty for 10 years and a limited power performance warranty for 25 years. The limited power performance warranty means that by the end of year 25, the panels’ actual power output will be no less than 80% of the labeled power output. Most of the inverters we install are warrantied for 10 years. Some brands offer an extended warranty.

What if I need a new roof or I am building a new house?

You want your roof to be in the best condition possible because the average working life span of a solar system is around 30 to 40 years.  Thus, we don’t recommend installation on composition shingle roofs over 10-years-old. If you are building a new house, click here for guidance on building a solar-ready home.

Can the solar panels withstand high winds and hail?

The panels are supported by high quality stainless steel and aluminum racking systems designed and mounted based on American Society of Civil Engineer (ASCE) wind load provisions. All solar panels are tested to UL-1703 standards and are capable of withstanding one inch (2.5cm) hailstones at 50MPH.  They are covered with tempered glass, akin to a car windshield.  Additionally, the panels can be covered by homeowners insurance.

What do I need to know about solar system installation?

We mount solar panels on your roof and run wires through conduit to a solar meter.  From there, we also run wires through conduit to your breaker panel.  In the same vicinity as your utility meter, we mount an inverter, AC disconnect, and the solar meter.  This equipment can be mounted either inside or outside and takes up about 15 square feet (3′ x 5′ area).

Will adding solar increase the value of my home?

Yes! A solar system reduces electric bills, and it is a valuable asset to any homeowner. Click here for a 2015 Berkley Lab & Sandia National Lab report summary showing an average selling price increase of approx. $4/watt ($15,000 for 4kW system).

Do I need approval from my homeowners association?

Some homeowners associations have rules regarding the installation of anything on your roof or grounds. If you belong to a homeowners association, contact them and ask about neighborhood guidelines.  In our experience, most homeowners associations decide in favor of solar system installations.

Which is for me - grid-tied, battery backup, or off grid?

We are frequently asked what happens when the grid is down and about batteries. Let’s review three types of solar systems; grid tied, battery backup and off grid. Which is for you?

 

GRID TIED

This is by far the most common, requires the least maintenance, and is the least expensive. It also receives the TVA Green Power Providers premium. However, grid tied systems are required to disconnect from the grid in the event of a power outage. This means you won’t have any power either. Whether this is an issue for you, depends on the individual. If you only lose power 2 or 3 times a year for an hour or 2, this shouldn’t be a problem. You can go out to dinner, see a movie, or just light a candle and have a glass of wine. Or you may be asleep or out of the house during the outage and not even know it happened, except for resetting a clock or two.

 

On the other hand, if you require electricity for medical purposes or live in an area with more frequent and sustained power outages, or live at the end of the distribution line (these are the last places to be restored), you may want to consider the other options.

 

BATTERY BACKUP (HYBRID)

This type system is grid tied but has batteries which provide emergency power. This is more expensive than grid-tied because of the need to have not only the batteries but equipment to charge the batteries, regulate them, provide over current protection and disconnecting means, an enclosure, more wiring, an emergency panel, transferring  emergency circuits from the existing panel to the emergency panel, and possibly an additional transfer switch. So if this significant expense is worth it to you, keeping in mind the batteries will have to be replaced in 5 to 10 years, then this may be a viable option for you. These systems will be a little less efficient than grid tied systems because the chemical reaction that charges the batteries takes energy. Additionally, energy is lost in the chemical conversion from the battery to the inverter when the batteries are drawn upon to provide electricity.

 

These backup systems are of 2 basic types, AC Coupled and DC Coupled. This refers to the coupling between the solar PV and the batteries, whether they connect to the system on the AC side or the DC side.

 

In a DC coupled system, the PV can charge the batteries directly with DC current via a charge controller. In this type system you may have one inverter with both grid tied and battery charging capabilities. The disadvantage to DC coupled is your strings (panel groupings) are usually limited to 150 volts, so you may only have 3 panels per string, for example. This means more wiring, and if there is too much distance between the panels and the batteries, as is frequently the case, you will need larger wire and conduit. One advantage to this system is it can be done with one inverter. However, these types of inverters are less efficient, and you will probably need two of them if you want 240 volts to feed through a Green Power Providers meter.

 

AC coupled systems, on the other hand, go from the PV to a grid tied inverter. Here the electricity is inverted to AC which will run loads that are present and at the same time send AC to a battery inverter that has a battery charger built in. Besides providing charge control to the batteries, this inverter inverts the batteries to AC which feeds an emergency panel in the event power goes out.  This type setup has the advantage of operating at a higher voltage on the DC side, in the range of 350 volts DC. This translates to less material required to wire the panels together and get that power to where it is going. It also provides the added benefit of more efficient transmission of power over a distance. For example, if its 200 or 300 feet from the array to the batteries, we can run a much smaller wire size than if we are going to a charge controller.

 

OFF GRID

Off grid systems have no connection to the grid at all. This requires a lifestyle that most people in the US aren’t used to, living without unlimited power on tap 24/7. Still thousands of people live this way because they make the right choices for it to be a viable lifestyle.  If you aren’t willing to live without central heat and air, a dishwasher, and some other electrical energy appliances, you may want to reconsider.  ‘The biggest factor might be – do you understand electrical energy? You will need to have a limited amount, as understanding kilowatt-hours and amp hours is vital to a successful system.

 

The solar power is stored in batteries and inverted with a special inverter that can also charge the batteries. Because more power is needed around the winter solstice, or December of each year, and this is also the period with the shortest days, most people use a generator during this period to assist the solar generation. Because the days are shorter, more light is needed. Because of wet and cold weather, people are inside more and using kitchen appliances, lighting, fans moving heat around, cooking, etc.

 

Myth: Off grid is cheaper than the electric company.

 

Sometimes people want to go off grid because its cheaper than the electric company. Wrong! If you want cheap, stay with the electric company. There are situations where the electric company wants say $50,000 to bring power lines to your remote location, and this can be a factor. If you have other reasons to get off the grid, plow ahead. Remember, you will be the plant operator and have full responsibility for your system, how much power you use and how you maintain it (especially the batteries).

 

Off grid is easier with vacation homes, get away retreats, hunting cabins, etc.  because they are not occupied 24/7 so you can save up power during the week for use on the weekend. The battery pack can be over sized relative to the PV to store electricity during the week for the weekends.

 

Most of our installations are grid tied. Next is battery backup, and last is the occasional off grid system. Having trouble deciding? We can install a grid tied system and come back in the future to convert it to an AC coupled battery backup system.  To do this you keep all your existing equipment, and we add a battery inverter, appropriate transfer switches, batteries, battery enclosure, battery monitoring, emergency panel, transfer circuits to the emergency panel and all the required electrical gear for a safe battery based backup system. By AC coupling the system, the solar panels don’t have to be rewired to a different voltage and you still get the benefit of the production incentive in the TVA Green Power Provider program.

 

So what is it you are looking for?  What is your situation and what do you want to accomplish?  Our job is to help you pick the right type system for you. Contact us so we can help you get a system up and generating and join the rapidly growing group of fuel free solar power generators.

NABCEP CERTIFICATIONS

The North American Board of Certified Energy Practitioners (NABCEP) is the most respected, well-established, and widely recognized certification organization for U.S. solar professionals. Our team includes 6 fully certified NABCEP Solar PV Professionals – more than any other firm in the region.

  • JP Plumlee
  • John Robinson
  • Daniel Hodge
  • Karl Jaeger
  • Steve Johnson
  • Matt Pelerossi

OUR PARTNERS

  • Sunpower Authorized Dealer
  • Tennessee Seia Solar
  • Amicus Solar Co-op
  • Solar Reviews