FAQ – Solar PV

Based on over 25 years experience in Scotlands solar industry we have compiled a very comprehensive list of questions that we often get asked. If you cannot find an answer to your question here please don’t hesitate to contact us by phone or email.
Q. How much space on my roof do I need for a solar PV installation?
Our grid connected systems start from around 1kW peak power, this occupies approximately 7 square metres of roof space.

Q. What is the output of a solar PV System?
For every kW peak power installed on a South facing roof the system will generate approximately 800-1000 kWh depending on location (according to the Goverment Issued Standard Assessment Procedure (SAP) calculations) . This is reduced by about 20% for installations on a East or West facing roof.

Q. How much does a Solar PV system cost?
Installed prices (excluding VAT at 5%) start from around £2500 – £3500 per kW peak power. There are NO grants available at the moment however this has been replaced with the Feed In Tariff (FIT) scheme.

Q. Will I be eligible for the new Feed In Tariff (FIT)?
The FIT pays up to 21.1p/kWh (<4kW peak power) for every kWh generated from the Solar PV System & an additional 3p/kWh for every kWh that’s exported. In order to be eligible for this scheme the system must be a MCS accredited product and MCS Certified installation. The Feed in Tariff will also rise annually at the rate of RPI.

Q. Do I need planning permission?
Solar systems do not need planning permission unless the property is listed or in a conservation area.

Q. Will my roof be strong enough?
Most roofs are strong enough to take a solar installation without any reinforcement.

Q. Do I need to inform my electricity supplier?
For systems below 16 Amps output (approx 3.8kW peak power) we will inform them once the installation is complete. For systems larger than 16 Amps we will require permission in advance from the network operator.

Q. What is the payback for a solar PV installation?
We would expect a system to pay for itself around 2-3 times times over the 25 year period. This is based on an annual fuel inflation of 6%,however Ernst and Young and the government’s new feed in tariff proposals estimate that this may rise to 12.9% annually.

Q. Will I be able to export any of the electricity I generate?
All unused electricity will automatically be exported, your electricity supplier can fit an export meter for you or they can pay you based on estimated export rates which can be as much as 50%

Q. How much money will I be paid for electricity I generate?
The Feed in Tariff pays up to 21.1p/kWh for all the electricity generated even if used in your own property and an additional 3p/kWh for all energy that is exported (totalling 24.1p/kWh). The Feed in Tariff will also rise annually at the rate of RPI.

Q. What is a kWh?
A kWh (pronounced ‘kilo watt hour’) is a specific amount of electricity. 1 Kwh is identical to 1 unit of electricity that is shown on your electricity bill. An electrical item having a rating of 1kW will consume 1kWh for every hour it is on at full power.

Q. What is the purpose of an inverter?
The PV panels generate direct current (DC), this is not directly compatible with the 240V alternating current (AC) that is used in your property. The inverter converts the DC power to AC power that can be used in your property.

Q. How does the electricity I generate get used in my appliances?
We connect the system to your fuse board (consumer unit). The electricity will automatically flow from there to wherever it is needed.

Q. Do I need a three phase electricity supply?
Systems up to about 10kW peak power can often be accommodated on a single phase electricity supply, however we do need to seek permission from your Distribution Network Operator (DNO). More than this will require 3 phases with the power split equally between them.

Q. Does your quotations provision for Scaffolding?
Yes, We include for scaffolding in our quotes

Q. Are there any grants available?
The (LCBP) low carbon buildings program closed it grants scheme early this year 2010 for electricity generating systems in February and introduced the Feed in Tariff. However, grants may be available from your local council, please contact them for details or do let us know if we can assist you and contact them for you.

Q. What is the difference between monocrystalline & polycrystalline PV panels?
Monocrystalline panels tend to be slightly more expensive than polycrystalline panels, however monocrystalline panels are regarded as having a higher output per kW peak power installed. Polycrystalline panels are a dark blue colour, they are of a cheaper quality and therefore not as efficient as the monocrystalline panels.

Q. What guarantees will I receive?
Panels generally have an output guarantee of between 20 and 25 years depending on manufacturer. Inverters normally have a guarantee of 5 years. Most other components and labour is usually guaranteed for 5 years. Check your quotation for specific details.

Q. Are your panels approved?
We only use the very highest quality of materials. The panels we use meet all the required standards including the MCS approval for government incentives.

Q. How are the panels fixed to the roof?
For s standard roof we use rigid stainless steel brackets that are fixed directly to your roof rafters. We do not use mastic/silicone to weather proof your roof. These techniques do not have a long life span but are frequently used by our lower quality competitors, if in doubt ask.

Q. How long will the installation take?
Installations generally take less than 1 day.  Larger systems may take slightly longer, but we will discuss this with you.

Q. How much do the solar PV panels weigh?
Panels can vary in weight dependant on the manufacturer, typically can range from 10-16 kgs per m2 installed