In Balance Energy

Solar & Electrical | Services & Systems

Home Services Systems About Contact

 

Solar Panels - PV System Sizing and Power Yield Calculator

Updated: December 2019, inc updated solar panel outputs and irradiance datasets

How many solar panels are needed to power a house? How much space is needed to put solar panels on a roof? Home much power will a new solar PV system produce?

The simple PV array size calculator below roughly estimates the amount of space a solar power system will take up on a roof and the amount of power the system might generate.

The given measurements are for unobstructed and unshaded areas of south facing roofspace i.e. ideal roofspace for installing solar panels. Any deviation from due south will see a reduction in power. Lower pitched roofs and roofs pitched at 45 degrees or greater than the 30 degrees used in the illustration, will also see a reduction in overall power generation.

In our opinion, in the UK, solar panels should not be installed on a north facing roof, significant reductions in power will also be seen on NW and NE roofs, any roof beyond due East or due West. Although power will be generated by solar panels installed on these roofspaces it is rarely worthwhile in terms of power generation to install on any northerly facing roof, in many cases often due to the roof itself shading these roofspaces as the sun rises in the East passing through South and setting in the West.

The more directly a solar panel faces the sun, the more light the panel will receive, the more power it will produce. It can achieve this best and will generate the most power throughout the course of the day by facing South. This being said East/West combinations can also be sensible design choices when based on a well matched time of day power usage requirement.

This calculator will definitely not be accurate for any real world system and should only be used to get a very quick idea of how much space a solar panel system might take up on a roof and how much power different combinations of solar panels will produce over a year. If you are thinking about installing solar also feel free to ask us for a kit price, advice on roofspaces including how you might work around shading and obstructions, for an estimate to supply and fit and or anything else you might need. Estimates and pricelists are provided with no obligation or sales pressure, we won't add you to a mailing list or share your data.

Back to Articles

Use this calculator to quickly estimate how many large solar panels you could fit onto a roof and roughly calculate how much power they could generate (kWhrs). The number of panels, the roof layout, the overall system size allowing space for roof mounting equipment and example power output figures (kWhrs) are provided for each system.

Solar panels: Length: 1675mm, Width: 1001mm, Output: 320 Watts (per panel)
Mounting: Roof mounted, South Facing, 30° roof pitch, No shading or obstructions.
MCS Irradiance Dataset: Zone 5E - Bristol and surrounding areas.

Energy output estimates are based on the following calculation:

kWhrs (kilowatt hours generated over a year) = kWp (max system size in kilowatts) x kk (Annual Solar Radiation (source: MCS Irradiance datasets) x SF (Shading Factor)

Solar Panels can be mounted in portrait or landscape to best fit the available space. The quickest way to use the calculator is to start from the width, then the height of the available mounting area and match the system size from there. Remember, where possible it is better to allow for space between the panels and the eaves, ridge and sides, mainly so wind can't get behind them and put pressure on their mounts. One of the services we include with our installations, offer separately and can include with kits is to carry out mounting system roof loading calculations.

This calculator should only be used for quick reference; let us know if you would like us to prepare something more accurate.

Another useful free tool that is easy to use and works well with the information provided in the tables below, but again should not be used for anythng other than rough calculations is the PVGIS solar estimation utility, where power output estimates can be generated using inputed roof pitch and location data.

Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 4 4 4.06m 1.68m 6.82m sq 1.280kWp 1233.92 kWhrs
Portrait 2 4 8 4.06m 3.37m 13.68m sq 1.96kWp 1682 kWhrs
Portrait 3 4 12 4.06m 5.06m 20.54m sq 2.94kWp 2524 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Landscape 1 3 3 5.06m 1m 5.06m sq 0.735kWp 631 kWhrs
Landscape 2 3 6 5.06m 2.02m 10.22m sq 1.47kWp 1262 kWhrs
Landscape 3 3 9 5.06m 3.04m 15.38m sq 2.2kWp 1888 kWhrs
Landscape 4 3 12 5.06m 4.06m 20.54m sq 2.94kWp 2524 kWhrs
Landscape 5 3 15 5.06m 5.08m 25.7m sq 3.67kWp 3150 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 5 5 5.08m 1.68m 8.53m sq 1.22kWp 1047 kWhrs
Portrait 2 5 10 5.08m 3.37m 19.55m sq 2.45kWp 2103 kWhrs
Portrait 3 5 15 5.08m 5.06m 25.7m sq 3.67kWp 3150 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 6 6 6.1m 1.68m 10.25m sq 1.47Wp 1262 kWhrs
Portrait 2 6 12 6.1m 3.37m 20.56m sq 2.94kWp 2524 kWhrs
Portrait 3 6 18 6.1m 5.06m 30.87m sq 4.41kWp 3786 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Landscape 1 4 4 6.76m 1m 7.92m sq 0.98kWp 841 kWhrs
Landscape 2 4 8 6.76m 2.02m 13.66m sq 1.96kWp 1682 kWhrs
Landscape 3 4 12 6.76m 3.04m 23.76m sq 2.94kWp 2524 kWhrs
Landscape 4 4 16 6.76m 4.06m 27.45m sq 3.92kWp 3365 kWhrs
Landscape 5 4 20 6.76m 5.08m 34.34m sq 4.9kWp 4206 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 7 7 7.12m 1.68m 11.96m sq 1.71kWp 1468 kWhrs
Portrait 2 7 14 7.12m 3.37m 23.99m sq 3.43kWp 2944 kWhrs
Portrait 3 7 21 7.12m 5.06m 36.03m sq 5.14Wp 4412 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 8 8 8.14m 1.68m 13.68m sq 1.96kWp 1682 kWhrs
Portrait 2 8 16 8.14m 3.37m 27.43m sq 3.92kWp 3365 kWhrs
Portrait 3 8 24 8.14m 5.06m 41.19m sq 5.88kWp 5047 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Landscape 1 5 5 8.45m 1m 9.9m sq 1.22kWp 1047 kWhrs
Landscape 2 5 10 8.45m 2.02m 19.8m sq 2.45kWp 2103 kWhrs
Landscape 3 5 15 8.45m 3.04m 29.7m sq 3.67kWp 3150 kWhrs
Landscape 4 5 20 8.45m 4.06m 34.31m sq 4.9kWp 4206 kWhrs
Landscape 5 5 25 8.45m 5.08m 42.93m sq 6.1kWp 5236 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 9 9 9.16m 1.68m 17.82m sq 2.2kWp 1888 kWhrs
Portrait 2 9 18 9.16m 3.37m 35.64m sq 4.41kWp 3786 kWhrs
Portrait 3 9 27 9.16m 5.06m 53.64m sq 6.61kWp 5674 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Landscape 1 6 6 10.14m 1m 10.14m sq 1.47kWp 1262 kWhrs
Landscape 2 6 12 10.14m 2.02m 20.48m sq 2.94kWp 2524 kWhrs
Landscape 3 6 18 10.14m 3.04m 30.83m sq 4.41kWp 3786 kWhrs
Landscape 4 6 24 10.14m 4.06m 41.17m sq 5.88kWp 5047 kWhrs
Landscape 5 6 30 10.14m 5.08m 51.51m sq 7.35kWp 6309 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 10 10 10.18m 1.68m 17.10m sq 2.45kWp 2103 kWhrs
Portrait 2 10 20 10.18m 3.37m 34.31m sq 4.9kWp 4206 kWhrs
Portrait 3 10 30 10.18m 5.06m 51.51m sq 7.35kWp 6309 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 11 11 11m 1.68m 19.8m sq 2.69kWp 2541 kWhrs
Portrait 2 11 22 11m 3.37m 39.6m sq 5.39Wp 4627 kWhrs
Portrait 3 11 33 11m 5.06m 59.4m sq 8.08kWp 6936 kWhrs
Panel Orientation No. Panel Rows No. Panel Columns Total No. Panels PV Array Width PV Array Height Mounting Area (m2) Max Power (Wp/kWp) Output (kWhrs, Year)
Portrait 1 12 12 12.22m 1.68m 20.53m sq 2.94kWp 2524 kWhrs
Portrait 2 12 24 12.22m 3.37m 41.18m sq 5.88kWp 5047 kWhrs
Portrait 3 12 36 12.22m 5.06m 61.83m sq 8.82kWp 7571 kWhrs

Top of page

Professional Solar PV System Design & Planning

The success of any renewable energy project is always in the quality and robustness of the system design, our experienced in-house design team has been designing innovative and ground breaking solar PV and other renewable energy systems since 2007.

Solar PV System Design
We take a collaborative and open approach and often find the very best systems are those where the system owner/developer has taken an active involvement with the design.

We can help prepare cost effective designs, roof layouts and documentation for all types and size of solar PV project; including drawings, bills of materials and detailed custom installation/owners manuals. We work with installers and developers as well as private clients and businesses, so if you need any technical information prepared then contact us, we have specialist knowledge and experience at your disposal, you will find us easy to work with and happy to help.

Solar PV System Design & Planning

Solar PV Equipment and Installation Kits

If we are supplying systems and equipment to Solar PV installers or for DIY solar installations, we are always happy to include system designs, testing and bespoke documentation as part of the package.

Solar PV Equipment Suppliers
This can include:
  • System Performance Statements
  • Line Drawings and Schematics
  • Roof Layouts
  • Grid Connection Documents
  • Solar Panel Testing and Records

Solar PV Systems & Equipment

 

Articles

Further reading and calculators related to designing, installing, repairing and maintaining solar photovoltaic and electrical systems:

Types of Solar Photovoltaic (PV) System

Introduction to the different types of Photovoltaic (PV) System available including Grid Tied, Off-Grid, Hybrid and Batteryless solar PV systems.

Solar PV System Components

Overview of the basic components needed to install a complete solar PV system. Introduction to solar PV panels. power inverters, AC & DC isolators and mounting systems.

Free Solar PV Calculators

A list of free solar PV calculators, solar design tools and software, Use to calculate solar yields and the Return on Investment (ROI) for solar PV systems.

Evaluating Solar PV Panels - Which panels to buy?

What to look for when evaluating and selecting solar PV panels for UK installations. Electrical characteristics of solar PV arrays and the safety factors used for selecting BoS equipment, also mounting options.

Flat Roof Solar PV Array Spacing / Shade Calculator

The minimum required space between parallel rows to avoid shading is decided by the height of the array immediately in front, the slope of the roof and the lattitude of the installation site. This table illustrates the different row spacings required for optimum positioning in different locations.

Engineering Recommendation G98

Grid Connections for Micro-Generators including Solar PV Systems and Elecricity Storage Systems in the UK. Under 16Amps Per Phase, grid synchronised.

Solar PV: Smart Export Guarantee

Interesting times ... The Smart Export Guarantee came into affect in January 2020. The Smart Export Guarantee is an obligation set by the government for licensed electricity suppliers to offer a tariff and to pay small-scale low carbon Generators and Micro-generators for any electricity that they export to the National Grid.

Solar Electricity - Frequently Asked Questions (FAQs)

How to size a system?, What is kWp?, What is the difference between a kilowatt (kW) and a kilowatt hour ( kWh)?, How does a solar PV system work? Can I add more solar panels to my system? How do I know if my solar panels are working?

Preparing for a Solar Panel Installation

As with any construction project the success and efficiency of a solar PV panel installation comes down to good planning. Some advice for potential system owners preparing for a new solar panel installation.

Planning Permission for Solar Photovoltaic (PV) Systems

A solar PV installation can be classed as 'permitted development' subject to conditions and when not located within a conservation area, AONB or world heritage site.

Solar PV, Safety & The Building Regulations

Residential PV systems notifiable under Part P. Special consideration needed for Part A. A combination of serious risks for solar PV installers.

Safely Retrofitting Solar PV Roof Mounts

The things to consider before installing a retrofited solar PV system on a roof and an introduction to the type of equipment used to secure an on-roof solar PV system.

Smart Switching / Solar PV Power Switching

Available as an addition to existing solar PV systems or installed as a package alongside a new system, Smart switching puts full control of a solar PV system's power output firmly in the hands of the system owner.

Solar Photovoltaic (PV) & Electrical Glossary of Terms

An alphabetical list of many of the industry and technical terms you are likely to come across when installing a solar PV system. The glossary also defines terms that are used in roofing and electrical work as well as in solar PV installation and solar manufacturing.

Mains Power Supplies & Earthing Systems

Mains Supply and Earthing Systems: Location & accessability, supply systems, earthing, bonding, labelling, installing RCDs.

Electrical Warning Signs & Labelling

A quick overview of some common electrical warning signs and labels that you might find attached to electrical equipment.

ABB / Power One Aurora Inverter Faults and Repairs

Power One, at one point were the second ranked inverter manufacturer in the world and there are many Power One Aurora Inverters installed in the UK. The most popular models being the Uno PVI-3.0-TL-OUTD and the Uno PVI-3.6-TL-OUTD.

Fronius IG / IG Plus Inverter Faults and Repairs

Fronius IG and IG Plus series inverters have LCD displays on the front of the chassis that providing it's working, will highlight any errors with the inverter or the solar PV system that it runs.

Mastervolt Inverter Faults and Repairs

Mastervolt Sunmaster and the smaller Soladin ranges of inverters were widely installed in the UK between 2011 and 2014. Popular Sunmaster models being the Sunmaster XS2000, Sunmaster XS3200 and the Sunmaster XS4300.

SMA Sunnyboy Inverter Faults and Repairs

SMA Sunnyboy Inverters have been widely installed in the UK, some of the most popular being the SB1200, SB2000 and SB3000. High frequency models include the SB2000HF, SB2500HF, and SB3000HF. Transformerless models include the SB3000TL and the SB3600TL.

SolarEdge Inverter and Optimser Faults and Repairs

The SolarEdge system is unique and in our opinion unrivalled in terms of it's ability to monitor system performance down to panel level. This is achieved through the installation of a small unit called an optimiser.

Sonnen Macht Inverter Faults and Repairs

The problem we often find with these inverters are damaged relays, the tell tale sign of a relay failure is an Error 19: Relay or Error 19: Relay Fault warning displayed on the inverter's display.

Top of page

Areas Served:

Swindon: Abingdon, Aldbourne, Andover, Banbury, Basingstoke, Bath, Berkshire, Bicester, Blunsdon, Box, Bracknell, Bradford on Avon, Bristol, Burford, Calne, Camberley, Carterton, Cheltenham, Chippenham, Chipping Norton, Chipping Sodbury, Cirencester, Corsham, Cricklade, Devizes, Didcot, Evesham, Faringdon, Fleet, Gloucester, Gloucestershire, Hampshire, Henley-on-Thames, Highclere, Highworth, Hook, Hungerford, Keynsham, Kingsclere, Lambourn, Lechlade, Lyneham, Maidenhead, Malmesbury, Marlborough, Marshfield, Melksham, Minety, Newbury, Oxford, Oxfordshire, Pewsey, Purton, Ramsbury, Royal Wootton Bassett, Salisbury, Shalbourne, Slough, Stow, Swindon, Tewkesbury, Thatcham, Trowbridge, Wanborough, Wantage, Warminster, Wiltshire, Winchester, Windsor, Witney, Wokingham, Worcester, Wroughton and Yate.

Torquay: Babbacombe, Bantham, Barnstaple, Bideford, Bodmin, Bridgewater, Brixham, Bude, Burnham-on-Sea, Chard, Cleveden, Cornwall, Crewkerne, Devon, Dorset, Exeter, Exmouth, Frome, Glastonbury, Holsworthy, Honiton, Ivybridge, Kingskerswell, Launceston, Lyme Regis, Lynton, Marldon, Minehead, Newquay, Newton Abbot, Okehampton, Painton, Plymouth, Salcombe, Seaton, Sidmouth, Somerset, Street, Stroud, Taunton, Tiverton, Torquay, Totnes, Wellington, Wells, Weston-super-Mer, Weymouth and Yeovil.

Derby: Ashbourne, Ashyby-de-la-Zouch, Bakewell, Beeston, Birmingham, Burton upon Trent, Buxton, Cannock, Cheadle, Chesterfield, Coalville, Congleton, Corby, Coventry, Crewe, Derby, Grantham, Kettering, Leek, Leicester, Lincoln, Long Eaton, Loughborough, Macclesfield, Matlock, Melton Mowbray, Newark-on-Trent, Nuneaton, Oakham, Peterborough, Sheffield, Sleaford, Stafford, Stamford, Stoke-on-Trent, Sutton Coldfield, Sutton-in-Ashfield, Swadlincote, Tamworth, Telford, Uppingham, Uttoxeter, Wigston, Wolverhampton and Worksop.

York: Barnard Castle, Barnsley, Beverley, Boroughbridge, Bradford, Bridlington, Burnley, Castleford, Darlington, Doncaster, Driffield, Easingwold, Goole, Halifax, Harrogate, Hartlepool, Helmsley, Hessle, Hornsea, Huddersfield, Hull, Keighley, Leeds, Malton, Manchester, Market Weighton, Middlesborough, North Yorkshire, Pocklington, Pontefract, Ripon, Rotherham, Scunthorpe, Selby, Sheffield, Skipton, South Yorkshire, Stockport, Thirsk, Wakefield, West Yorkshire, Wetherby, Whitby, Withernsea, York and the Yorkshire Dales.

East London Basildon, Barking, Bexley, Blackheath, Braintree, Brentwood, Brixton, Bromley, Burnt Oak, Canvey Island, Chatham, Chelmsford, Cheshunt, Chigwell, City of London, Croydon, Dagenham, Dartford, Dulwich, Edgware, Enfield, Essex, Gravesend, Grays, Greater London, Grenwich, Harlow, Hatfield, Hertfordshire, Hornchurch, Ilford, Kent, London Docklands, Maidstone, Mill Hill, Orpington, Peckham, Rainham, Rayleigh, Rochester, Romford, Sevenoaks, Sidcup, Southend-on-Sea, Stoke Newington, Stratford, Tilbury, Waltham, Walthamstow, Westminster, Wickford, Woodford and Woolwich.

Residential - Commercial - Agricultural - Industrial

©2007 - 2020 In Balance Energy Ltd