Solar panels FAQs
PV stands for Photo (light) Voltaic (Electric). Solar PV panels convert light in to electricity. Note the word light, not sunlight. They continue to produce electricity on cloudy days. It’s just that their output will be higher, the brighter the light is. This is not new technology – the use of light to produce electricity dates back to the 19th Century.
Inverters change the DC current from the panels to AC current needed for your home and the grid. It’s essential the correct type of inverter is used and that they’re located in the right place. Many installers always put them in the loft, but this can be detrimental to your system. Cornwall Solar Panels are meticulous about inverter choice and placement.
Our solar team have absolutely zero financial motivation to push particular products because their salaries are not commission based. Cornwall Solar Panels was formed in 2010 by Tony Sampson because he had a passion for green energy and saw that there was a great opportunity to take Solar energy away from the ‘double-glazing style’ hard sell pushy sales approach and offer customers a genuinely informed choice. We’re committed to remaining 100% impartial and can install any Solar PV products on the market. And frequently do – because every home and every business is different.
Your inverter monitors grid voltage and ensures that it is putting the power from your inverter into your system at a slightly higher voltage than the grid. Voltage is best thought of as pressure, the force behind the electric. If the inverter produces a higher voltage when you switch an electrical appliance on it will naturally use the power from the panels first.
A 4kWp system in Cornwall on an unshaded south facing roof can generate over 4000 units (kWh) per year. If your roof is East or West facing you’re still likely to generate 3400 units (kWh) per year. The average household in the UK uses around 3200 units per year, so living in Cornwall is a definite benefit! Depending on when and how you use your electric depends on how much impact your PV system will have on your bills. With a bit of information about your electric usage and habits, Cornwall Solar Panels can produce incredibly accurate bespoke forecasts thanks to their PV Sol modelling software.
Cornwall Solar Panels use PV Sol software to accurately calculate your expected output. PV Sol accurately takes in to account panel performance, inverter performance, shading, roof pitch, roof orientation and your local weather data to calculate how much electric you will generate. We then include these figures and how much money you are likely to earn, based on your usual usage and the amount that will be returned to the grid.
You will simply draw from the grid in the normal way. But remember, it doesn’t have to be sunny to generate electricity.
The excess energy will be sold back to the grid.
Yes. Properties are required to have an EPC grade D or above to get the full Feed In Tariff. Cornwall Solar Panels can check to see if your property has one. If you fall below a D grade, Cornwall Solar Panels can check to see if adding Solar PV will lift the grade to a D, advise on what other measures might help obtain a D and arrange for an EPC assessment, if required, at a cost of £60.
Cornwall Solar Panels use a Professional PV design software package called PV Sol. We can build a 3D model of your property to see which panels will fit best on your roof. There are over 400 panel manufacturers in the PV Sol database and every panel listed has details of the panel’s performance.
No, leave that to us. Cornwall Solar Panels are accredited to notify all their work to Building Control.
On Domestic roofs, the brackets used fix to the rafters of your roof which ensures the fabric is free from loadings.
Commercial roofs vary in construction and there are many different mounting solutions for every different scenario.
For the safety of linesmen who may be repairing the fault, your inverter will need to shut down. There are some battery systems that will allow you to have back up power in the event of a power cut. These are still expensive and normally cost prohibitive.
Cornwall Solar Panels use their own fully qualified tradesmen. A domestic system team is made up of a qualified roofer, a labourer and a qualified electrician.
Domestic size installations take 1-2 days to install, however typically domestic installations are completed within one day.
Commercial installations can take longer, depending on the size of the site and the specific requirements of your business.
FIT (Feed In Tariff) is the government-backed scheme which means your electric supplier (eg EON, N-Power, EDF, Utility Warehouse etc) will pay you for every unit that your system generates, whether you use it or if it goes back in to the grid. More info on FITs is available on the Energy Saving Trust website.
Payback depends on many variables including quality of panels and inverters, your local weather conditions, shading, pitch and orientation of your situation. Typically in Cornwall you can expect to pay a system off in 6 – 8 years.
You would have to check with your landlord. We’ve installed Solar PV for many landlords as they can benefit from the Feed in Tariff, increase in property value and increase in rent.
There is currently no mounting system to put Solar PV panels on thatched roofs. You may be able to have a ground mounted Solar PV system.
Yes, PV solar panels can be fitted to a roof, even if there is no access to the loft.
Many customers also install heat pumps. These take the small amount of heat in the air or ground and extract it to help heat homes and provide hot water. They run on electric and save huge amounts on people’s bills. They need a very specialist installer like Source Energy. They work in a similar way to CSP as they are heat pump specialists and have won UK Heat Pump installer of the year twice!
You property needs to meet Energy Performance Certificate grade D or above to get the full Feed In Tariff. Cornwall Solar Panels can check to see if your property has one. If it’s below a D grade we can check to see if adding Solar PV will lift the grade to a D, advise on what other measures might help obtain a D and arrange for an EPC assessment if required (at a cost of £60).
If your property is grade E,F or G you will still get some FIT, Cornwall Solar Panels can calculate very accurately how much your return will be to help you decide if it’s worth it or not.
No, Solar PV panels work on light and all roofs have light shining on them. Many customers have fitted east/west facing systems and typically generate around 86% of the same roof should it be facing south.
Solar PV panels vary greatly in efficiency so one panel may generate 250watts while another panel of the same physical size may generate 345watts, therefore it’s not how many panels you need but how much power you need. Domestic systems usually aim for 4kWp which is made up of 12 – 16 panels, depending on the quality and efficiency of the panels chose.
Yes, but the cost of systems is coming down too, so as a Return On Investment for Solar PV remains the same. The Government target is for a 8% ROI, however in Cornwall domestic system can reach 16% ROI and Commercial systems can reach 30% ROI. The FIT is reviewed every 3 months, many of these reviews result in no change to the FIT, if it does change then the reduction of FIT is no more than 3.5%. As the Export tariff and savings on your bill are not affected the overall effect on your benefits is less than 2%.
Solar PV panels gradually degrade over time. Typically they will lose around 15% of their power over 25 years with some high quality panels only degrading around 2.5% over 25 years. This also varies depending on the quality of the panel. Cornwall Solar Panels use PV Sol software which allows us to forecast very accurately the impact of any degradation.
There are advances in technology, however these are aimed more at using different materials, e.g. hiding PV technology in glass. These advances do not show any progress in efficiency so are unlikely to become mainstream. The technology we see in today’s Solar PV panels is the same technology that was used to power some satellites in the early 70s. There are some small incremental advances but these are not expected to change dramatically at the moment.
Shading will reduce the power output of solar panels and any panels connected to that panel. Cornwall Solar Panels can calculate exactly what impact your shading will have with their 3D modelling software PV Sol. Severe shading, like a chimney right in front of panels can also cause some long term damage. CSP will be able to advise you of the best place for your panels to be installed.
Almost every panel on the market has diodes these days and they don’t completely stop the effects of shading, however they do help.
Monocrystalline panels will give more power per square meter. This might not mean that the panel is better than a high quality polycrystalline panel. There are many, many factors that affect the quality of a panel, this is just one of them and efficiency is only a critical factor if you have a limited amount of space.
Inverters are electric and electronic equipment so they’re best off being kept cooler. We usually recommend installing them in a garage, utility room or some models can be mounted outside. We advise that the loft is a poor place to install the inverter as they get very hot and in particular will get hottest on the day you want your inverter to work its hardest. This will reduce the output from the inverter and age its components quicker. We know that installing in the loft is easier and quicker and that the slightly shorter cable run may also have an impact. However, it’s a poor trade off as the extra loss in longer cables is more than offset by the extra production and life that you’ll get from your inverter. Another advantage of having the inverter where you can see it is that you can check that your system is working properly. Inverters have a display that tells you if everything is running smoothly. If this display is in the loft then you won’t know anything is wrong until you get the Christmas decorations out!
You will get paid FIT for 20 years from the date that you register. You keep the rate from the date of registration with your energy supplier and the rate will also follow the RPI (Retail Price Index) each April, which means your investment retains its value.
If you’re in a listed building, or the panels are more than 200mm from your roof (eg ground mounted, a normal roof mount system is within 200mm of the roof) or a conservation area you will need planning permission. This certainly does not mean it’s a “NO!”. We have had many customers request planning and have it granted. The planners are very sympathetic to renewables as it is a necessity to reduce the UK’s CO2e footprint.