Want to talk?
Our advisers are ready to answer any queries you may have, call us on
0844 504 1317

Quick Online Quote

FREE Site Survey
4 kwp roof mounted solar panels Ground mounted solar panels 4kwp House roof with solar panels

Solar Panel FAQs

Frequently asked questions about producing your own electrical energy with solar photovoltaic (PV) panels

  1. How does solar photovoltaic (PV) generation work?
  2. What is the feed-in tariff scheme?
  3. How do feed-in tariffs work?
  4. How much will I get paid for my solar electricity?
  5. Will solar power substitute my utility bills?
  6. How much solar electricity will it actually produce?
  7. How much space will I need for solar panels?
  8. Would the solar panel installation cause any disruption to me and my property?
  9. How long will it take to install solar panels?
  10. Do I need planning permission?
  11. What happens if I move house?
  12. Do solar arrays require a lot of maintenance?
  13. Does a solar PV installation come with any warranties?
  14. How much do solar panels cost?

1. How does solar photovoltaic (PV) generation work?

Each solar module/panel is made up of solar cells which are composed of semi-conducting materials. Each PV cell conducts energy from the absorption of daylight causing a flow of electrons which in turns produces electricity on demand. Only a small amount of electricity is produced from a single cell so many cells are connected to form a solar panel. Multiple panels are then joined together to produce what is known as a PV array.

PV arrays are then rated in peak watts (Wp) which is identified by the amount of energy a particular array of panels can produce in perfect conditions. For example a 1kWp system would produce an estimated 1kW of electricity at midday when the sun is at its highest point and not obstructed by clouds.

A PV array will supply electricity via an inverter which converts DC electricity to AC electricity (the same as what we are supplied through the grid). The inverter will be connected at the mains fuse box and the whole system will be grid linked by Solar Power Intl. so that any excess electricity can be exported to the national grid.

Dorset and the rest of the south west has an excellent source of solar to plug into. The average south facing roof inclined at 30 degrees can receive a remarkable 1100-1200 kWh of solar radiation per square meter a year. This means that a 2kWp PV array (using approx. 16sqm of roof space) installed on a south facing roof here in the south west can be expected to produce 1800kWh of electricity per annum. On average this is around half of the average households annual electricity requirements.

For the life of the system there will be no maintenance required, although we do advise the odd obligatory wipe maybe by you or your window cleaner once a year! Every system we install comes with both a manufacturer guaranteed performance for 25 years and as a company we offer all our customers a 5 year workmanship warranty along with a call out service in case our customers should face any faults with their installations.

2. What is the feed in tariff scheme?

The purpose of the feed in tariff scheme is to incentivise investment in renewable energy throughout the UK in order to help us achieve the legally binding target of 15% of total energy from renewables by 2020 (up from 2% in 2009). It is also designed to spur households into cutting their carbon footprints to enable households to significantly contribute towards the UK’s reduction in carbon emissions.

Anyone taking up the offer of the feed in tariff will be guaranteed the current tariff at the time the system is commissioned, this rate is then paid quarterly for 20 years. 

The feed in tariff provides 3 fundamental benefits to those investing in Solar PV:


3. How do the feed in tariffs work?

The scheme is funded by the British population’s energy bills. A carbon levy bill is incorporated into the electricity bills of every UK energy user. This then goes to provide renewable generators with a 20 year guaranteed support payment for all the electricity they produce.

Licensed electricity suppliers supplying energy to over 50,000 domestic customers are mandated to join the scheme. These suppliers are known as FIT licensees. FIT licensees are required to take their customers who install solar power through the registration process, take regular meter readings and make tariff payments. Solar Power Intl. will provide the support and a handover pack to ensure that you comply with the necessary obligations in order to receive your payments. A list of FIT licensees can be found at the Ofgem website.

Ofgem is also responsible for ensuring that utility companies comply with the feed in tariff requirements.

4. How much will I get paid for my solar electricity?

The rate you receive per kilowatt hour your system produces depends on its size. The table below shows the tariff rates that you can expect.

All tariffs are index linked.

System type

System size

Tariff level  p/kWh

Tariff lifetime (years)


<4 kWp (retrofit)




<4 kWp (new build)




>4 – 10 kWp




>10 – 50 kWp




>50 – 150 kWp 




5. Will Solar Power substitute my utility bills?

The average household’s energy consumption for a three bedroom house is 4200 kwh a year. A solar PV array is likely to produce 3600kwh a year.

This supply is not constant (unless you opt for a battery storage system), and we have to bear in mind that more energy will be produced in the summer than the winter.  The panels produce no energy at night. Consequently we can say that you will at least be making a 50% saving on your electricity use. However if you change your patterns of energy use such as using more electricity during the day (such as doing your laundry and your dishwashing) and if you increase the efficiency of your home these savings could significantly increase.

The short answer is they are unlikely to substitute your utility bills (particularly for domestic sized systems) but they will significantly reduce them.

6. How much solar electricity will it actually produce?

The amount of electricity your solar PV system produces will depend on the daylight hours it is exposed to which can differ depending on the region in which is it located and the orientation of the panels. The amount of energy that each system produces also depends on the efficiency of the panels and the size of your total array.

The Energy Savings Trust estimates that an array mounted on a southerly facing pitch in this region can expect 901kwh per kWp to be produced per annum. This sum is based on average annual daylight hours that we receive in this region. You may well be surprised, but Dorset and the rest of the south west region actually have an excellent solar resource.

So we can expect an average 4kWp domestic system installed on an average three bedroom property to produce 3604kwh a year.

The Energy Savings Trust website has an excellent Cash Back Calculator which will give you the chance to estimate the annual electricity production and returns on investment that you could expect from your solar PV installation.

7. How much space will I need for solar panels?

A typical solar PV system requires around 7m2 of space per kWp installed. For example a typical 4kWp installation would fit comfortably on a roof that is 7m x 4 in dimensions.

If you are not sure of the dimensions of your roof feel free to contact us with your full address and post code and we will be able to take a look at the measurements of your roof and give you an estimate for the size of system you could install on the pitch you have available.

8. Would the solar panel installation cause any disruption to me and my property?

Disruptions over the installation period are minimal. Other than a bit of wiring inside the majority of work is done on your roof. Installing solar PV doesn't make any noise and will only require scaffolding for a maximum of 2 days.

9. How long will it take to install solar panels?

Commercial installations can take as little as two days to complete (depending on the size).  Most domestic installations take only one day.

10. Do I need planning permission to install solar panels?

Solar PV installations don’t usually require any planning permission at all. Any system will be permitted unless:

We advise anyone in doubt to contact their local planning authority.

11. What happens if I move house?

An Energy Savings Trust survey has identified that 1/3rdof the British population would be willing to pay more for a home with a solar PV installation. And why wouldn’t they? Not only are they inheriting an income with the property that they are buying, but they are also escaping the clutches of ever increasing utility costs.

This survey doesn’t stand alone. Previous research reported in the Guardian newspaper states that installing a renewable energy system to your property can add up to 9% to its value. It might also be noted that this report was taken in 2006 before Feed in Tariff were added to the equation. Certainly Chris Holmes spokesperson for the national improvement show urges that the retail value of your home could rise by approximately 5%, so not a bad move in this existing property market. He states that ‘Retrofitting a home can be the ultimate responsible home improvement’. There is no doubt that estate agents are becoming increasingly accomplished at selling households with solar PV systems installed.

So not only will you be paid back while you use your solar PV electricity for the 20 years after it is installed, allowing many systems to be paying for themselves within 7 years as it is, but you will also be reaping the rewards when you sell your house.

12. Do solar arrays require a lot of maintenance?

Solar PV requires virtually no maintenance at all. We advise that you check your array annually for debris such as leaves, dust or bird dropping and occasionally they may need to be cleaned with soapy water and a soft bristled brush but other than that they can be left to operate themselves. Part of the beauty of solar PV is there reliability.

13. Does a solar PV installation come with any warranties?

All our solar PV panels come with up to 25 year manufacturer’s warranty. Our inverters also come with at least 5 years warranty and as a company we offer a further 10 year, insurance backed warranty to cover our workmanship and equipment. At Solar Power Intl we also offer our customers a call out service in case you face any problems or need assistance after the installation has taken place.

14. How much does a solar panel installation cost?

An average domestic installation of 4kWp would cost approx £5,800. For the larger projects over and above 10kWp the cost per kWp can be significantly reduced based on bulk purchase and supply. There is also the option for businesses to opt for a free system (the Feed-in tariff is not received by the business but electricity generated by the system is sold back to the customer at a heavily reduced rate through a Power Purchase Aggreement). Use our online quote calculator or contact us today for your free quotation.

Solar Panels:

Domestic Solar PV Panels - Quick Quote
Commercial Solar Panels - Quick Quote
Free Commercial Systems

Useful tools and Information:

Cash Generator for Solar PV
Technical Information about:
Solar PV Panels, Solar Invertors, Mountings
FITs Information

About Solar Power Intl:

Why Choose Solar Power Intl
Our Solar Installation Map
Contact Us:
Phone Solar Power Intl on 0844 504 1317 : 0844 504 1317
@ : sales@solarpowerintl.co.uk

Copyright © 2018 Solar Power Intl    Dorset web designers - The Web Booth