Frequently Asked Questions

How much does it cost? In order to determine the exact cost of any given system, an analysis of the site has to be preformed. This is referred to as a site survey. Issues involving shade, access, system sizing and existing electrical service are just a few of the considerations that must be evaluated. Those concerns but aside, a typical PV system will cost approximately $25,000. This is based on a 3Kw grid-tied, roof mounted system and does not take into account the federal tax credit and any local rebates. Beginning January 1, 2009 PV systems will be eligible for a 30% tax credit. This tax credit offsets you federal income tax liability and can be carried over. This federal credit can pay up to $7,500 of a $25,000 PV system, cutting your out of pocket cost to $17,500. A reduction in system size will reduce initial cost but decrease you savings on electrical use. Generally the cost of a system is approximately $8.33 per watt. Additionally Austin Energy (for Austin Energy customers only) will rebate $4.50 per a watt, capped at $13,500. This rebate is applied before calculating your federal rebate. A rebate on the example $25,000 3Kw system would be (3000 x $4.50) $13,500. This would reduce your cost to ($11500 - 30%) = $8050. The savings you incur on your electric bill can pay for this example system in as little as 7 years. For more information on rebates and credits click here. Lambent Energy has partnered with Clean Power Finance, your one stop shop for financing your PV system. For additional information on financing click here. How much time does it take? Grid-Tied PV Systems There are a number of steps that must be undertaken prior to and following the installation of a grid-tied PV system. These include but are not limited to, permits, authorization, inspections and applications. The process of approvals and inspections can change depending on city, HOA, and utility provider. The processes usually take a few weeks. The installation of the PV system generally takes several days to a week to complete. The installation is followed by further inspections. Final design approval to an operational system can be done in as little as 5 weeks. Weather and inspection scheduling are common delays that may increase the total time to 8 weeks. Grid-Tied PV with Battery Backup Systems Battery backup grid tied system go through the same processes are normal grid tied system, but require additional installation time. These systems typically take from 6 to 10 weeks. Stand Alone Battery Systems Stand Alone battery systems usually do not require exhaustive permitting and inspection. Systems used for powering auxiliary equipment, like lights, pumps and remote locations can be installed rather quickly. Stand Alone systems typically take from 4 to 6 weeks to design, install and test. What steps are required? Lambent Energy will take care of the many steps involved regardless of the system. Below are a few of the steps necessary when installing a PV Grid-Tied system. Several of these steps are unnecessary if the system is not grid tied. This list is representative of the process and not a definitive list. Site survey System design Proposal HOA, Utility and City permits and applications Scheduling Rebate, incentive application(s) Installation Electrical Utility and city inspection Customer training Does my HOA or city have rules regulating the installation of Solar Systems Most cities and home owners associations have some rules governing the installation of PV systems. Lambent Energy will work with your city and HOA and carefully follow the guidelines set forth by both. Lambent Energy always takes the necessary step in making your system esthetically pleasing, unobtrusive and ideal for you, your HOA and the city. Does roof angle and direction effect Solar Systems? The short answer to this question is, yes. Roof angles between 12 - 45 degrees allow most PV systems to operate at near peak levels. Although the preferred installation direction is south, roofs facing SW, SE and even east and west are good candidates for PV. Solar power output decreases proportionally with a horizontal angle, or "azimuth," greater than 15° from due south. Most people are surprised to find out that the angle of a PV panel does not have to be set at a perfect tilt and exact south direction. Although there is a set angle when optimum efficiency is achieve. The approximate angle of peak efficiency for a perfect south installation is equal to the latitude of the location (on summer solstice). Because the sun swings with the seasons this angle varies, but modern PV panels operate at 95%-100% efficiency with angle variations up to 35 degrees. While using PV modules is very simple, the mathematics describing their angular relationship to the sun is very difficult. Latitude of Site Tilt Angle for 0 deg. South 0-15° 15º 15-25° Same as latitude 25-30° + 5° to local latitude 30-35° + 10° to local latitude 35-40° + 15° to local latitude 40° + + 20° to local latitude Most roofs have at least one direction and angle location that will provide for practical, efficent use of a PV system. For additonal information on PV technology vist the US Department of Energy's PV website. Are any permits required? There are different requirements for the various types of PV systems. Almost all cities charge PV installers a permit fee. The fee covers services that cities perform to ensure installations meet engineering and safety standards. Lambent Energy takes care of all the red tape associated with the process. Cities whose inspectors are most knowledgeable about PV systems usually cover their permitting expenses with a fee of $300 or less for standard, average sized systems. Unfortunately, some cities base permit fees on system valuation or are not so familiar with PV, and charge far more. What licensing and certifications are required? In Texas all grid tied PV systems require a licensed electrician and code compliant system installation. Lambent Energy installers are all NABCEP certified. All systems are UL listed and certified safe, code compliant and reliable by local inspectors and Lambent Energy. We take every necessary step in assuring your system will be dependable, safe and good looking. How long is the equipment and installation guaranteed? Lambent energy guarantees installation workmanship for a period of 15 years. The warrantee on most grid tied invertors is 15 years, while most of the PV panels are guaranteed to provide efficient service for 20 years. Batteries and charging systems vary greatly. Your proposal will detail the warrantee period of each of the important pieces of your system. Lambent Energy has relationships with the leading PV suppliers and is constantly researching the reliability and warranty periods of new products. It's in the best interest of you and Lambent Energy to install the most dependable, longest lasting system available. We do not deal with no-name, untested products. Every component will be carefully selected from a list of field proven, reliable products. What happens when I need to replace my roof? Should your roof require replacing, Lambent Energy recommends the system be deactivated and temporarily removed. If you find yourself replacing the roof due to weather damage, your homeowners’ policy should pay the additional cost associated with the temporary removal. Roof mounted systems are installed on a railing system that allows for a straight forward disassembly and reassemble. A quick disconnect located near your electrical service box and meter is all that is required on the power side. We will gladly work with your roofer in scheduling the temporary removal and reassembly of the panels, roof mounted conduit and railings. Some PV installer may suggest that systems can be left in place during roof replacement and in fact the system will protect the roof directly underneath. Any good roofer who wants to warrantee his work will want to replace the roof in its entirety. A system left in place during roof reconstruction is also an accident waiting to happen. Will I receive a credit from the electric utility if I generate more energy than I use? The short answer to this question is Yes. The 1978 federal Public Utility Regulatory Policy Act specifies that local utilities must buy individuals and businesses excess renewable-generated power at "avoided" or wholesale cost. Different utility companies have different policies, but all are required to buy or credit you. Some utilities and states have incentive based buy backs, allowing you to get paid more per kilowatt than you purchase each for. Currently most Texas utilities will credit you at wholesale, while charging you retail. The formulas and details vary by utility. Lambent Energy includes your specific policy in the graphs and charts that are part of your proposal. Although it's possible to run your meter backwards. It not likely useless you make an effort to do so. An average unoccupied, un-airconditioned Texas house on a sunny day with an average size system may experience more production than use for brief periods. As solar radiation decreases and usage increases, overall gains decline. You should expect an average system to offset your energy consumption by 10% - 25%. What size system do I need? Your budget, the available rebates and incentives, along with roof or yard area restrict the size of a system. An average system will be approximately 3kW, while the smallest financially practical system is 1kW. If budget and available area allow, a larger system should be considered. It's possible to install a system that satisfies all you energy needs and more. What about the vents on my roof? Roof vents come in many shapes and sizes. Each will have to be evaluated during system design. Lambent Energy will map all roof venting during the site survey and design a system with them in mind. PV systems can be designed to go around some vents as long as shading from the vents themselves is not a problem or on top of others (certain attic vents only). Many times the systems can simple avoid the vents all together. While under some situations a vent must be relocated. During your site survey a Lambent Energy technician may discuss the venting he or she identifies as obstacles. Your proposal will detail any stacks or vents that intrude in the installation area. How do I know my system is working? Beyond seeing your electric bills plummet. The basic PV systems today include a display which monitors the status of the system. This display can be augmented with a remote display which can be mounting indoors. Allowing you to monitor and track the system output and performance. Additionally the system can include internet monitoring, making the performance information available to you in real time from anywhere. For more information on system monitoring, visit our system monitoring section.

If these answers have not addressed your questions or you would like additional information, please contact us and a solar specialist will gladly answer your questions. For detail information on PV (Photovoltaic) systems please click here to visit our resource page.