Common Mistakes to Avoid When Hiring a Solar Installer
Choosing the right solar installer is one of the most important decisions you'll make when investing in solar energy. A poor choice can lead to underperforming systems, voided warranties, safety hazards, and thousands of pounds in remedial costs. Yet many homeowners and businesses rush this critical decision, focusing solely on price rather than quality and credentials.
This comprehensive guide reveals the most common mistakes people make when hiring solar installers and provides actionable advice to help you protect your investment and ensure a successful installation.
Quick Navigation
- Why Choosing the Right Solar Installer Matters
- Mistake #1: Going with the Cheapest Quote
- Mistake #2: Not Checking Installer Certifications
- Mistake #3: Skipping Research on Company Reputation
- Mistake #4: Not Getting Multiple Quotes
- Mistake #5: Ignoring Warranty Details
- Mistake #6: Failing to Ask About Experience
- Mistake #7: Not Verifying Insurance Coverage
- Mistake #8: Overlooking the Contract Fine Print
- Mistake #9: Not Asking About Permits and Inspections
- Mistake #10: Choosing an Out-of-Area Installer
- Mistake #11: High-Pressure Sales Tactics
- Mistake #12: Not Understanding the Equipment
- Mistake #13: Ignoring Post-Installation Support
- Mistake #14: Not Verifying Subcontractor Use
- Mistake #15: Skipping Site Assessment Quality
- Essential Questions to Ask Before Hiring
- Solar Installer Red Flags Checklist
- What a Professional Solar Installer Should Provide
- How to Properly Vet a Solar Installer
- Protecting Your Solar Investment
- Frequently Asked Questions
Why Choosing the Right Solar Installer Matters
Your solar panel system represents a significant investment for both domestic and commercial solar projects. Unlike purchasing a consumer product with simple returns, solar installation involves complex electrical work, structural considerations, and long-term performance commitments spanning 25-30 years.
The installer you choose directly affects system performance and energy generation. Poorly designed or installed systems can underperform significantly—in severe cases by 15-25% or more compared to properly specified installations. Even modest underperformance of 10% compounds over a 25-year lifespan, potentially meaning thousands of pounds in lost energy savings and export income through the Smart Export Guarantee.
Perhaps most importantly, only installations completed by MCS-accredited installers qualify for government incentives. If your installer lacks proper certification, you won't be eligible for payments when exporting surplus electricity to the grid, significantly impacting your return on investment.
The True Cost of Poor Installation
Remedial work on poorly installed solar systems can prove costly. Issues range from minor repairs to serious problems involving multiple panel replacements and inverter faults. In severe cases, complete system replacement may be required due to fundamental design flaws or safety hazards. Roof damage from improper mounting, electrical faults from substandard wiring, and water ingress from poor sealing are among the most common issues requiring expensive repairs.
Mistake #1: Going with the Cheapest Quote
Price comparison is sensible, but selecting solely based on the lowest quote is perhaps the most common and costly mistake solar buyers make. Unusually low quotes almost always indicate corners being cut somewhere, whether in equipment quality, installation standards, or aftercare provisions.
Why Lowest Price Is Often a Red Flag
Solar installation costs include equipment (panels, inverters, mounting systems), labour, design work, DNO applications, permits, warranties, and business overheads. When one quote comes in significantly below others, something has been reduced or removed from this equation. Common cost-cutting tactics include using lower-tier equipment with shorter warranties, rushing installations without proper quality checks, skipping important steps like structural assessments, and minimising post-installation support.
A reputable solar installation service will explain exactly what's included in their pricing and why certain components or processes are necessary. Transparency about costs indicates professional operation.
Hidden Costs in Low-Ball Quotes
Cheap quotes often exclude essential elements: scaffolding hire, DNO application fees, electrical certification, or adequate warranty coverage. Always request fully itemised quotes and compare like-for-like. What appears to be significant savings upfront could result in substantial additional expenses, repairs, or lost generation over the system's lifetime.
Mistake #2: Not Checking Installer Certifications and Licences
In the UK solar industry, certifications aren't optional extras—they're fundamental requirements that protect consumers and ensure installation quality. Yet many buyers fail to verify credentials before signing contracts.
Essential Certifications to Verify
MCS Accreditation (Microgeneration Certification Scheme) is the most critical certification for UK solar installers. MCS-accredited companies undergo rigorous assessment, maintain quality management systems, and submit to regular audits. Crucially, only MCS-certified installations qualify for Smart Export Guarantee payments. Verify any installer's MCS status directly through the official MCS database before proceeding.
Electrical Competency Certification through schemes like NICEIC, NAPIT, or ELECSA confirms the installer can self-certify electrical work under Part P building regulations. Without this, separate electrical inspection and certification adds cost and complication.
Manufacturer Certifications from panel and inverter brands indicate installers have received product-specific training. This matters for warranty support, as some manufacturers require installation by certified partners to maintain warranty validity.
How to Verify Credentials
Don't simply take an installer's word for their accreditations. Visit the MCS Find an Installer database and search for the company name. Check that their certification covers solar PV installation (not just solar thermal or other technologies). Verify their NICEIC or equivalent electrical registration through the relevant scheme's online lookup.
Request copies of certificates and check expiry dates. Legitimate installers will happily provide this documentation—reluctance to share credentials is itself a red flag.
Mistake #3: Skipping Research on Company Reputation
Even certified installers vary significantly in quality, customer service, and reliability. Thorough reputation research helps identify companies that consistently deliver excellent results versus those with concerning patterns.
Start with online reviews across multiple platforms including Google, Trustpilot, and industry-specific sites like Which? Trusted Traders or Checkatrade. Look for patterns in feedback rather than focusing on individual reviews. Consistent mentions of communication problems, installation delays, or poor aftercare suggest systemic issues.
Check how companies respond to negative reviews. Professional installers address concerns constructively and work to resolve issues. Defensive or dismissive responses indicate attitudes that could prove problematic if you encounter difficulties.
Local reputation matters particularly for ongoing support. Ask neighbours, colleagues, or local community groups about their experiences with solar installers in your area. Word-of-mouth recommendations from people you trust often prove more valuable than anonymous online reviews.
Signs of a Reputable Installer
Look for: established business history (ideally 5+ years), verifiable portfolio of completed installations, willingness to provide contactable references, active engagement with industry bodies, transparent pricing and processes, and clear communication throughout initial enquiries.
Mistake #4: Not Getting Multiple Quotes
Obtaining multiple quotes isn't just about finding the best price—it's essential for understanding what constitutes reasonable scope, specification, and cost for your specific installation. Three quotes from MCS-accredited installers should be considered the minimum.
Why Three Quotes Is the Minimum
Different installers may propose varying system sizes, equipment brands, and installation approaches. Comparing multiple proposals reveals the range of options available and helps identify both overpriced quotes and suspiciously cheap ones. With three quotes, you can recognise outliers and understand the "reasonable middle ground" for your project.
Our free quote service provides detailed proposals with clear specifications, allowing meaningful comparison with other installers.
Comparing Apples to Apples
Ensure quotes specify the same information for valid comparison. Key details to match include total system capacity (kWp), panel manufacturer and model, inverter type and brand, mounting system specification, warranty terms for equipment and workmanship, what's included (scaffolding, DNO applications, etc.), and estimated annual generation.
Price differences of 10-15% between comparable quotes are normal, reflecting different business overheads and margins. Variations of 25%+ usually indicate significant specification differences or concerning pricing approaches.
Get Your Free Solar Assessment
Receive a detailed, transparent quote from our MCS-accredited team with clear specifications you can compare against other installers
Request Your Quote Speak to Our TeamMistake #5: Ignoring Warranty Details
Warranties protect your investment over decades, yet many buyers gloss over warranty terms in their eagerness to proceed. Understanding exactly what's covered—and what isn't—prevents unpleasant surprises when issues arise.
Types of Solar Warranties
Panel Product Warranties cover manufacturing defects, typically for 10-15 years with quality brands. Panel Performance Warranties guarantee minimum output levels (usually 80-85% of rated capacity) after 25-30 years. Inverter Warranties range from 5-12 years standard, with options to extend to 20-25 years. Workmanship Warranties from your installer cover installation quality, typically 2-10 years depending on the company.
Reputable installers using quality equipment should offer comprehensive warranty packages. Our guide to installing solar PV explains warranty considerations in detail.
Warning Signs in Warranty Terms
Be cautious of warranties that require specific maintenance schedules that weren't disclosed upfront, exclude "consequential damage" from defective equipment, only cover parts without labour costs, are backed by the installer rather than the manufacturer (concerning if the installer ceases trading), or contain vague language about coverage scope.
Warranty Red Flags
Short workmanship warranties (under 2 years), excessive exclusion clauses, requirements to use only the original installer for servicing, and warranties that transfer to third-party insurers rather than being manufacturer-backed all warrant careful consideration before proceeding.
Mistake #6: Failing to Ask About Experience
Solar installation combines electrical work, construction skills, and system design expertise. Experience matters significantly—installers who've completed hundreds of installations have encountered and solved problems that newcomers haven't yet faced.
Years in Business: Established companies demonstrate sustainability and commitment to the industry. At Spectrum Energy Systems, we've been designing and installing solar systems since 2011, giving us extensive experience across diverse installation scenarios.
Installation Volume: Ask how many systems the company has installed. Higher volumes indicate operational efficiency and broad experience, though quality should never be sacrificed for quantity.
Relevant Experience: If you have specific requirements—complex roof geometry, listed building constraints, or commercial installation needs—ask about experience with similar projects. Request examples or case studies demonstrating relevant expertise.
Local Knowledge: Installers familiar with your area understand local planning requirements, DNO processes, and typical roof constructions. This local expertise streamlines installations and reduces unexpected complications.
Mistake #7: Not Verifying Insurance Coverage
Proper insurance protects both you and the installation team. If an uninsured or underinsured installer damages your property or a worker is injured on your premises, you could face significant liability.
Required Insurance Types
Public Liability Insurance covers damage to your property and third parties. Minimum coverage of £2 million is standard, with £5 million preferable for larger projects.
Employers' Liability Insurance is a legal requirement for companies with employees, covering workplace injuries. Verify this exists if the installer uses employed staff rather than exclusively self-employed contractors.
Professional Indemnity Insurance covers design errors and professional advice. This matters particularly for complex installations where incorrect system design could affect performance.
Request copies of current insurance certificates and verify they haven't expired. Legitimate companies provide this documentation without hesitation.
Mistake #8: Overlooking the Contract Fine Print
Solar installation contracts should clearly document everything discussed during sales conversations. Verbal promises mean nothing if they're not written into the agreement.
Critical Contract Elements
Your contract should specify exact equipment to be installed (manufacturer, model numbers, quantities), total price including VAT with payment schedule, installation timeline with key milestones, warranty terms for all components, who handles DNO applications and associated costs, permit responsibilities and costs, commissioning procedures and handover documentation, cancellation terms compliant with Consumer Contracts Regulations, and procedures for variations and additional work.
Red Flags in Contracts
Concerning contract elements include large upfront deposits (more than 25% before work begins), vague equipment descriptions ("high-efficiency panels" rather than specific models), missing or unclear completion dates, no mention of permits or DNO applications, and excessive penalty clauses for cancellation.
Your Cancellation Rights
Under Consumer Contracts Regulations, you have 14 days to cancel contracts signed away from business premises (including your home) or concluded remotely. Legitimate installers respect these rights and explain them clearly during the sales process.
Mistake #9: Not Asking About Permits and Inspections
Solar installations require various approvals and certifications. Understanding who handles these processes—and associated costs—prevents surprises during installation.
DNO Notification and Approval
All grid-connected solar installations require notification to your Distribution Network Operator (DNO). Systems under 3.68kW typically need only notification (G98), whilst larger systems require formal application and approval (G99). Your installer should handle this process, but confirm this is included in their quote. Our team manages all DNO applications and grid connection procedures as standard.
Building Regulations and Planning
Most domestic solar installations fall under permitted development, but installations on listed buildings, in conservation areas, or exceeding certain criteria require planning permission. Electrical work must comply with Part P building regulations, typically satisfied through MCS certification or separate electrical notification.
Clarify who is responsible for determining permit requirements, submitting applications, and obtaining approvals. Discovering mid-installation that planning permission was needed creates costly delays and potential enforcement issues.
Mistake #10: Choosing an Out-of-Area Installer
National solar companies and travelling installers may offer competitive prices, but local installers typically provide superior service, support, and accountability.
Benefits of Local Installers
Local companies respond faster to warranty issues and service calls. They understand regional planning requirements, local DNO procedures, and typical building constructions in your area. Their reputation within the community creates accountability that distant companies lack.
At Spectrum Energy Systems, we focus on the East Midlands—Nottinghamshire, Derbyshire, Leicestershire, and Lincolnshire—allowing us to provide responsive local service whilst maintaining the expertise of an established installer. Our Lincoln solar installation page demonstrates our local focus.
National installers may struggle to provide timely aftercare, particularly for warranty issues. When your system needs attention, waiting weeks for an engineer from another region proves frustrating and costly in lost generation.
Mistake #11: Being Pressured by High-Pressure Sales Tactics
Legitimate solar installers don't need aggressive sales techniques—their products and services sell on merit. High-pressure tactics indicate companies prioritising quick sales over customer satisfaction.
Common Pressure Tactics to Recognise
"Today only" pricing that disappears if you don't sign immediately is a classic pressure technique. Genuine special offers allow reasonable consideration time. Creating artificial urgency ("prices are rising next week," "limited equipment availability") pressures decisions without allowing proper evaluation.
Door-to-door salespeople working on commission may push aggressively for signatures. Cold-calling companies often have concerning business models focused on volume rather than quality.
Take Your Time
Quality solar investment deserves proper consideration. Any installer unwilling to let you review quotes, check references, and compare options isn't confident their offering can withstand scrutiny. Walk away from anyone pressuring immediate decisions.
Mistake #12: Not Understanding the Equipment Being Installed
You don't need engineering expertise, but understanding basic equipment specifications helps evaluate proposals and avoid substandard components.
Panel Quality Indicators
Panel manufacturers are typically categorised into tiers based on financial stability, manufacturing quality, and bankability. Tier 1 manufacturers (LONGi, JA Solar, Canadian Solar, Trina, etc.) offer reliable products with dependable warranty support. Lesser-known brands may offer lower prices but with uncertain long-term warranty backing.
Key specifications to compare include efficiency rating (18-22% for quality panels), power output per panel, temperature coefficient, and warranty terms. Our guide to choosing solar panels explains these factors in detail.
Inverter Considerations
Inverters convert DC panel output to useable AC electricity. Quality inverters from established brands (Fronius, SolarEdge, Enphase, GoodWe, Solis) offer reliability, monitoring capabilities, and warranty support. Understanding whether your system uses micro inverters or string inverters helps you evaluate suitability for your specific installation.
Ask installers why they recommend specific equipment. Knowledgeable professionals explain their choices based on your requirements rather than simply installing whatever they have available.
Mistake #13: Ignoring Post-Installation Support
Installation day isn't the end of your relationship with your solar company—it's the beginning of 25+ years of system operation. Post-installation support significantly affects long-term satisfaction and system performance.
Monitoring System Setup
Modern solar systems include monitoring capabilities showing real-time and historical generation data. Your installer should properly configure monitoring, create your account access, and explain how to interpret the information. Effective monitoring helps identify performance issues early.
Maintenance Services
Whilst solar systems require minimal maintenance, periodic checks ensure optimal performance. Ask about maintenance service availability, response times for issues, and whether maintenance packages are offered.
Clarify how warranty claims are handled. Does the installer coordinate with manufacturers, or must you manage claims directly? Who covers labour costs for warranty repairs? Understanding these processes before installation prevents frustration later.
Mistake #14: Not Verifying Subcontractor Use
Some solar companies operate primarily as sales organisations, subcontracting actual installation work. This model can work well if managed properly, but creates risks if subcontractors are poorly vetted or supervised.
Questions About Labour
Ask directly whether installations are completed by employees or subcontractors. If subcontractors are used, enquire about vetting procedures, supervision arrangements, and who bears responsibility if issues arise.
Companies using their own employed teams typically offer better quality control, consistent workmanship, and clearer accountability. Our installations are completed by our own qualified engineers rather than outsourced subcontractors.
Mistake #15: Skipping Site Assessment Quality
Thorough site assessment is essential for accurate system design and reliable performance estimates. Rushed or superficial assessments lead to problems during installation or underperforming systems.
What Proper Assessment Includes
A comprehensive site survey examines roof structure and condition, orientation and pitch angles, shading from trees, buildings, and other obstacles, available roof space and optimal panel placement, electrical infrastructure and consumer unit capacity, cable routing options, and access requirements for installation.
Some companies conduct assessments remotely using satellite imagery and customer-provided photos. Whilst this can work for straightforward installations, complex sites benefit from physical surveys identifying issues not visible remotely.
Assessment Red Flags
Be wary if installers provide quotes without seeing your property, rush through site visits in just a few minutes, don't check your consumer unit or electrical system, fail to discuss shading or roof condition concerns, or can't explain how they calculated performance estimates.
Essential Questions to Ask Before Hiring
Prepare these questions when meeting potential installers. Their responses reveal professionalism, expertise, and suitability for your project.
Certification Questions
- Are you MCS-accredited for solar PV?
- Which electrical certification scheme are you registered with?
- Can you provide copies of current certificates?
- Do you hold manufacturer certifications for proposed equipment?
Experience Questions
- How long have you been installing solar systems?
- How many installations have you completed?
- Have you worked on properties similar to mine?
- Can you provide contactable references?
Equipment Questions
- Why do you recommend these specific panels and inverter?
- What warranties come with each component?
- Who backs the warranties if you cease trading?
- Are there alternative equipment options to consider?
Process Questions
- Who handles DNO applications?
- What's the typical installation timeline?
- Will the same team complete the entire installation?
- What documentation will I receive at completion?
Solar Installer Red Flags Checklist
Use this checklist to identify potentially problematic installers. Multiple red flags should prompt serious reconsideration before proceeding.
↔ Swipe table left/right to view all columns
| Red Flag | Why It Matters |
|---|---|
| No verifiable MCS accreditation | Installation won't qualify for SEG; indicates lack of quality standards |
| Door-to-door sales only | Often high-pressure tactics; commission-driven rather than quality-focused |
| No physical business address | Difficult to pursue if problems arise; may indicate transient operation |
| Refuses to provide references | Suggests lack of satisfied customers or poor track record |
| Won't provide written quotes | Prevents comparison; leaves room for later price changes |
| Demands large upfront payment | Increases your risk; may indicate cash flow problems |
| Vague equipment specifications | May substitute inferior products; prevents informed comparison |
| "Today only" pricing pressure | Prevents proper evaluation; genuine offers allow consideration time |
| No workmanship warranty | Leaves you unprotected against installation defects |
| Negative review patterns | Consistent complaints indicate systemic problems |
What a Professional Solar Installer Should Provide
Quality installers distinguish themselves through comprehensive, transparent service. Here's what to expect from professional operators.
Before Installation
Detailed written proposals specifying exact equipment, system size, and pricing. Clear explanation of expected performance with realistic generation estimates. Comprehensive warranty documentation explaining all coverage terms. Financing options explained where applicable. Timeline for installation with key milestones.
During Installation
Professional conduct and site management. Regular communication about progress. Clean, safe working practices. Respect for your property and neighbours.
After Installation
Complete handover documentation including MCS certificate, electrical certificates, equipment warranties, user manuals, and performance data. Monitoring system properly configured with account access provided. Explanation of system operation and maintenance requirements. Clear contact information for support and warranty queries.
View our case studies to see examples of professional installation documentation and processes.
Experience Professional Solar Installation
With over 14 years of experience and MCS accreditation since establishment, we deliver installations you can trust
Get Your Free Quote Learn About UsHow to Properly Vet a Solar Installer
Follow this systematic approach to thoroughly evaluate potential installers before making your decision.
Step 1: Verify Credentials - Check MCS database for active accreditation. Verify electrical scheme registration. Request and review insurance certificates.
Step 2: Research Reputation - Read reviews across multiple platforms. Check Companies House for business history. Search for news articles or industry recognition.
Step 3: Request Detailed Quotes - Obtain at least three comparable quotes. Ensure all include same specification detail level. Compare equipment, warranties, and inclusions.
Step 4: Contact References - Ask for recent customer contacts. Enquire about installation experience, any issues, and how they were resolved.
Step 5: Evaluate Communication - Assess responsiveness and professionalism. Note whether questions are answered fully. Consider whether you'd trust this company for 25+ years.
Step 6: Review Contract Carefully - Read every clause before signing. Clarify anything unclear. Ensure verbal promises are documented.
Protecting Your Solar Investment
Taking time to choose the right installer protects your substantial solar investment and ensures you enjoy the full benefits of renewable energy for decades to come. Rushed decisions based on price alone frequently lead to regret, whilst careful evaluation leads to successful, high-performing installations.
Remember that quality solar installation is a long-term partnership. The company you choose will be responsible for warranty support, system maintenance, and potentially future upgrades over 25+ years. Investing time upfront to find the right partner pays dividends throughout your system's operational life.
Frequently Asked Questions
Make an Informed Decision
Avoiding these common mistakes when hiring a solar installer significantly increases your chances of a successful, trouble-free installation that delivers excellent returns for decades. The solar industry includes many excellent, professional companies—but also some who cut corners or prioritise sales over service.
By verifying credentials, researching reputations, comparing quotes properly, and understanding what to expect from professional installers, you protect yourself from costly mistakes and ensure your solar investment achieves its full potential.
At Spectrum Energy Systems, established in 2011, we're proud to meet every standard outlined in this guide. Our MCS accreditation, NICEIC certification, transparent processes, and commitment to customer satisfaction have earned us a strong reputation across the East Midlands. We welcome the scrutiny that careful buyers apply—because we know our work stands up to inspection.
Whether you're considering domestic solar panels for your home or commercial solar installation for your business, we're here to provide honest guidance and professional installation you can trust.
Ready to Start Your Solar Journey?
Get a transparent quote from an installer you can trust. No pressure, just honest advice from MCS-accredited professionals with 14+ years of experience.
Request Your Free Quote Contact Our TeamAbout Spectrum Energy Systems: Established in 2011, we're MCS-accredited solar installers serving Nottinghamshire, Derbyshire, Leicestershire, Lincolnshire, and the wider East Midlands. From initial consultation through installation to ongoing maintenance support, we deliver comprehensive solar solutions that maximise your investment. Explore our homeowner's guide to solar panels or complete business solar guide for more detailed information.
