Solar Design Software UK: Which Platform for British Installers?

UK solar installers work with a different set of compliance requirements from their US or European counterparts. G98 and G99 DNO notifications, MCS 012 design standards, the MCS Product Directory, and SEG financial projections all need to flow naturally from the design process — not be retrofitted from a tool built for another market.

This comparison covers the main solar design software platforms available to UK installers as of 2026, with specific attention to how each handles the UK compliance workflow.

What UK Installers Actually Need from Design Software

Before comparing tools, it is worth being specific about what “UK-compatible” means in practice:

G98/G99 single-line diagram: The DNO notification process requires a single-line electrical diagram showing inverter model, protection relay settings, generation meter, and grid connection point. G99 applications particularly require detailed protection data. Software that generates a generic single-line diagram may still require manual annotation for UK DNO submissions.

MCS 012 design output: MCS 012 requires documented yield assessment, shading analysis, string configuration, and equipment list using MCS Product Directory-listed items. The documentation needs to be present in installation files for certification body surveillance visits.

UK irradiance data: UK solar resource calculations should use data derived from UK Met Office records, ERA5 reanalysis, or PVGIS (which covers GB well). Tools using only NREL TMY data for the US may have limited or lower-quality UK location coverage.

SEG financial modelling: Customer proposals in the UK should include SEG earnings projections. A proposal built on US net metering assumptions will need significant manual adjustment.

UK proposal templates: UK customers expect proposals that reference their energy tariff (p/kWh), their current electricity bill, and the system’s payback period in years — with SEG income shown separately from self-consumption savings.

Feature Comparison Table

SurgePV

Best for: UK residential and commercial installers who need G99-compliant documentation, MCS 012 output, and customer proposals in a single workflow.

SurgePV is built to handle the complete UK solar installer workflow: design, simulate, propose, and generate compliance documentation. The UK compliance focus is built in rather than patched on.

G98/G99 workflow: SurgePV generates G99-ready single-line diagrams with protection relay settings pre-populated based on the inverter model selected. The diagram format is structured to meet DNO application requirements, reducing or eliminating the need to redraw diagrams in CAD tools before submission. For G98 systems, notification form templates are provided alongside the standard system documentation.

MCS 012 documentation: The design workflow outputs the documentation MCS assessors look for — shading assessment with energy yield impact, string configuration summary, equipment list with MCS Product Directory cross-reference, and commissioning record templates. For MCS-certified installers, this means design and documentation happen in one step rather than two.

UK irradiance data: SurgePV uses UK Met Office-sourced and ERA5 reanalysis data for energy yield calculations, ensuring production estimates reflect actual UK solar resource rather than generic European averages.

SEG proposals: Customer proposals show self-consumption savings and SEG export earnings separately, using current tariff data. Proposals are formatted for UK customers — p/kWh pricing, annual payback calculation, 25-year cashflow, and a comparison against the customer’s current electricity bill.

Strengths:

• G99 SLD generation with inverter-specific protection settings
• MCS 012 commissioning documentation as standard output
• UK weather data and UK-specific financial modelling
• Solar proposals formatted for UK customers with SEG projection
• Shadow analysis integrated with energy yield calculation
• End-to-end workflow: no separate tools needed for design vs documentation

Considerations:

• Subscription-based pricing
• Primarily designed for professional installers — not suited to DIY or single-site owner use

Aurora Solar

Best for: UK installers who prioritise 3D shading analysis quality and customer-facing proposal design, and are comfortable supplementing with separate documentation tools for G99 and MCS compliance.

Aurora Solar is one of the most widely deployed solar design platforms globally, with strong 3D roof modelling capability and polished customer proposals. It has a growing UK user base, particularly among residential installers who have adopted it for its shade tree analysis and customer-facing outputs.

UK-specific capabilities: Aurora offers UK location support and has improved UK irradiance data coverage in recent versions. However, the platform was built primarily for the US market. G99 single-line diagrams require manual annotation to meet UK DNO application requirements. MCS commissioning documentation is not natively generated. SEG financial modelling requires manual setup.

Strengths:

• Best-in-class 3D shading model, including LIDAR-based shade analysis where data is available
• High-quality customer proposal templates
• Well-established platform with strong onboarding and support resources
• Large global user base and active development

Considerations:

• G99 SLD output requires supplementation for UK DNO applications
• MCS 012 documentation not natively produced
• SEG earnings not natively included in proposal financial model
• Financial modelling built around US incentive structures — requires manual UK configuration
• Higher cost at enterprise scale

OpenSolar

Best for: UK installers looking for a free-tier option with reasonable UK market coverage and basic proposal functionality.

OpenSolar offers a free tier that covers core design, simulation, and proposal functions. It has made deliberate efforts to support non-US markets, including the UK, and includes PVGIS irradiance data that gives reasonable UK coverage.

UK-specific capabilities: OpenSolar uses PVGIS data for UK energy yield calculations, which provides acceptable accuracy for residential design work. Proposal templates can be customised and adapted for UK format. SEG earnings can be included in financial projections with manual configuration.

Strengths:

• Free tier available — meaningful for sole traders and small installers
• PVGIS irradiance data covers UK reasonably well
• Active development with growing international market support
• Reasonable residential design workflow

Considerations:

• G99 single-line diagram generation is limited — typically requires supplementation
• MCS 012 specific documentation not natively produced
• Free tier has design and project limits; paid plans required for volume work
• Less suited to complex commercial projects
• Support resources thinner than Aurora or SurgePV

Helioscope

Best for: UK commercial solar designers who need engineering-grade energy simulation accuracy for large or complex systems, and handle documentation separately.

Helioscope (owned by Folsom Labs, now part of the Aurora Solar group) is recognised for very accurate energy simulation, particularly for commercial and utility-scale projects with complex array configurations, multiple roof planes, or ground-mounted systems with near-field shading.

UK-specific capabilities: Helioscope supports UK locations and uses meteorological data sources that provide reasonable UK coverage. However, it was not designed with UK regulatory compliance documentation in mind. G98/G99 forms, MCS documentation, and UK customer proposals are all outside the scope of the tool.

Strengths:

• Industry-recognised simulation accuracy for commercial projects
• Detailed shading and irradiance loss reporting (useful for MCS 012 shading assessment evidence)
• Good for multi-section commercial roof and carport design
• Trusted by engineering teams for production guarantee modelling

Considerations:

• Not a compliance documentation tool — G99, MCS, and proposals all require separate processes
• Residential workflow is not optimised
• Customer proposal quality significantly below Aurora or SurgePV
• Additional cost on top of any compliance or proposal tool
• Helioscope and Aurora Solar now share ownership — product roadmaps may converge

PVsyst

Best for: UK engineering consultants and designers who need peer-reviewed simulation accuracy for commercial, utility, or technically complex projects — not for MCS residential workflow.

PVsyst is the simulation tool of reference for solar energy yield assessment in professional engineering practice. Lenders, insurers, and technical due diligence teams accept PVsyst reports as a standard for production guarantee modelling on larger commercial and utility projects.

UK-specific capabilities: PVsyst supports Meteonorm weather data which covers UK locations well. Its simulation engine handles complex configurations: bifacial modules, tracker systems, partial shading, terrain topography. For projects where bankable yield assessment is required, PVsyst is the standard tool.

Strengths:

• Best-in-class simulation engine for engineering-grade accuracy
• Widely accepted in technical due diligence for project finance
• Bifacial, tracker, and ground-mount modelling
• Detailed loss breakdown and uncertainty analysis

Considerations:

• Not a field installer tool — steep learning curve, engineering-focused interface
• Does not generate MCS documentation, G99 forms, customer proposals, or commissioning records
• Licence model (not SaaS subscription) — upfront cost plus annual maintenance
• Standalone simulation tool — must integrate with other tools for the rest of the project workflow

How to Choose for Your UK Workflow

For MCS-certified residential installers (volume): Solar design software that generates G99 SLD, MCS 012 documentation, and UK proposals in one workflow is the priority. Separate documentation tools create process overhead that compounds at volume. SurgePV is specifically built for this combination.

For smaller installers or sole traders starting out: OpenSolar’s free tier covers core design and basic proposals without upfront cost. As volume grows, the documentation gap will become a limiting factor — plan for the transition to a full-featured platform before compliance becomes a bottleneck.

For commercial solar designers: SurgePV handles commercial G99 and MCS documentation well. For projects requiring bankable yield assessment (project finance, EPC performance guarantees), PVsyst is the standard for the simulation component — used alongside SurgePV for design documentation and proposals.

For installers prioritising shading analysis quality: Aurora’s LIDAR-based 3D shading is a differentiator on complex residential rooftops. For UK installers where shading is a particular sales objection or technical challenge, Aurora’s shading model justifies the manual G99/MCS documentation overhead.

The Documentation Gap Problem

The most common pain point for UK installers using US-market or general-purpose solar software is what might be called the documentation gap — the difference between what the software produces and what MCS 012 and DNO applications actually require.

In practice, this gap is filled by:

• Manual CAD redraws of single-line diagrams (30–90 minutes per project)
• Spreadsheet-based NEC/BS 7671 calculations for string voltage, cable sizing, and OCPD
• Word processor templates for commissioning records
• Separate yield simulation in PVGIS for MCS 012 shading evidence

Every project in this gap costs time. At 100 installations per year, 45 minutes of manual documentation per project is 75 hours — roughly two full working weeks annually. At 300 installations, it is six weeks.

Solar software that closes this gap — producing the G99 SLD, yield report, and commissioning template as a natural output of the design workflow — converts documentation time directly into installation capacity.

Solar designing workflows built around UK compliance standards eliminate the most common cause of delayed DNO applications and MCS certification body non-conformances: incomplete or inconsistent documentation.

Frequently Asked Questions

What does solar design software need to do for UK installers specifically?

UK-specific requirements include: G98/G99 documentation (single-line diagram with protection relay settings, DNO notification form support), MCS 012 design output (yield calculation, shading assessment, system drawing), UK weather/irradiance data (Met Office or ERA5-sourced, not US NREL data), UK-format customer proposals with SEG earnings projections, and commissioning record templates formatted to MCS requirements. Software built primarily for the US market may lack several of these.

Can Aurora Solar be used for UK solar projects?

Yes, Aurora Solar can be used for UK projects and has a growing UK user base. However, it was built primarily for the US market. UK-specific features such as G99-format single-line diagrams, MCS commissioning documentation, and SEG financial projections require manual supplementation or are handled outside Aurora. For straightforward residential design and proposal work, Aurora is functional in the UK; for compliance-heavy workflows, installers typically supplement it with additional documentation tools.

Is PVsyst suitable for MCS solar design in the UK?

PVsyst is an engineering-grade simulation tool used by designers and engineers for accurate energy yield assessment. It does not generate MCS commissioning documentation, customer proposals, or G98/G99 forms. UK installers use PVsyst for simulation accuracy on commercial or technically complex projects and use a separate tool (or manual process) for MCS documentation and customer-facing output.

Does SurgePV work with UK DNO G99 applications?

Yes. SurgePV generates G99-ready single-line diagrams with protection relay settings pre-populated for UK inverter models, formatted to ENA Engineering Recommendation G99 requirements. The diagram output can be attached directly to a DNO G99 application without redrawing. G98 notification forms are also supported for smaller residential systems.

This guide is part of the UK Solar Compliance hub. For grid connection requirements, see the G98 vs G99 guide. For the MCS certification process, see the MCS certification guide.