When you’re researching solar panels for your Northern Ireland home, the sheer number of options can feel overwhelming. Should you focus on price? Quality? Warranty? What’s actually worth paying attention to?
The truth is, most people focus only on cost and miss critical differences that affect how much you’ll save over 25 years. This guide walks you through exactly what to compare so you can make a decision you won’t regret.
Why Comparing Solar Panels Matters
Solar systems vary significantly in price, efficiency, durability and warranty coverage. Two 6kW systems might differ by £2,000 to £3,000 between installers, and these differences usually reflect real quality variations rather than just business overhead.
The trap most homeowners fall into is choosing based on price alone. That’s understandable, but it’s where the real mistakes happen. A system that costs £500 more upfront often saves thousands in maintenance and replacement costs over its 25-year lifespan.
A proper comparison weighs price against performance, reliability, warranty and installer reputation. Let’s look at each factor.
What System Size Do You Actually Need?
Before comparing anything else, you need to know what size system your home requires.
System size depends on two things: your annual electricity consumption and available roof space. A typical household uses 2,500 to 4,000 kWh annually, which usually requires 4 to 8kW of installed capacity. Your specific needs depend on:
- Your current annual kWh usage (check your electricity bills)
- Available roof space (south or southwest-facing roofs work best)
- Your roof angle and orientation
- Whether you want battery storage
Here’s a quick sizing rule: if your annual usage is 2,500 kWh, a 5kW system is usually appropriate. If it’s 4,000 kWh, aim for 7 to 8kW. Each kW of installed capacity generates roughly 700 to 800 kWh annually in Northern Ireland.
Panel Quality and Efficiency
Not all solar panels are created equal. Quality varies significantly and this directly impacts your energy generation and how long the system lasts.
Efficiency Ratings
Panel efficiency tells you how much sunlight converts to electricity. Modern panels range from 18% to 22% efficiency. A 1% difference in efficiency means roughly 5% to 10% more energy generation over 25 years.
Compare panels with efficiency ratings of 20% or higher for best results. Lower-efficiency panels cost less upfront but generate less energy in limited space, so you’d need more panels to reach your target output.
Panel Brands and Tiers
Industry analysts categorise solar panels into tiers based on manufacturer reliability and track record. Knowing these tiers helps you understand why quotes vary so much.
Tier 1 manufacturers have 25+ years in business with strong warranty support and highest efficiency. Examples include Canadian Solar, Trina and JinkoSolar. You’re paying for proven reliability here.
Tier 2 manufacturers have been around 10 to 20 years and offer solid quality. Examples include Q Cells and Longi. These represent good value – quality products without the premium pricing.
Tier 3 includes newer or less established brands. Variable quality and potentially limited support. These are budget options and you’re taking more risk.
The recommendation: choose Tier 1 or Tier 2 panels. The £200 to £500 premium per system pays for itself through better efficiency and reliability over 25 years.
Understanding Inverters
The inverter converts DC electricity from your panels into AC electricity for your home. It’s the second most important component after the panels, yet often overlooked.
You have three main options:
String inverters use one central unit and are the most common choice. Cost-effective but less efficient if panels receive partial shading.
Microinverters put one unit per panel. Better performance with shading but significantly higher cost (£2,000 to £3,000 extra). Worth it if your roof receives patchy sunlight.
Hybrid inverters include battery storage capability. Essential if you want to add storage later.
When comparing quotes, check the inverter type, warranty length (10 years standard), and monitoring capabilities. Better inverters include real-time app monitoring so you can track performance.
What’s Included in Solar Quotes
Price varies significantly across Northern Ireland. You’ll see 6kW systems priced anywhere from £9,000 to £14,000 depending on installer and components.
What these prices typically include:
- Hardware: panels, inverter, racking, wiring
- Installation labour
- Electrical certification and compliance
- Roof assessment and structural work (if needed)
- Building regulations approval
When comparing three quotes for the same system size, make sure you’re checking:
- Panel brand and efficiency rating (same brand and rating as other quotes?)
- Inverter type and brand
- Warranty coverage: panels (typically 25 years), inverter (10 to 12 years), workmanship (10 years)
- Roof work included or charged separately?
- Is monitoring included?
- Building regulations approval included?
If two quotes are identical system specs but differ by £2,000, the cheaper option likely cuts corners somewhere. Usually that’s on installation quality or using lower-tier components elsewhere.
Choosing the Right Installer
The installer matters as much as the components. Poor installation reduces efficiency by 5% to 15% and creates warranty headaches.
Look for these credentials:
- MCS certification – required for government grants and Feed-in Tariff eligibility
- NICEIC or Trustmark accreditation – demonstrates electrical competence
- Customer reviews – check Google, Trustpilot, and Which? ratings
- How long in business – established companies (5+ years) carry less risk
- Clear warranty claim process – responsive aftercare matters when issues arise
- References – can they provide customer contact details you can actually verify?
When an installer gets these basics right, you’re much more likely to have a smooth experience.
Calculating Your Return on Investment
The real test is which system gives you the best return on investment.
Payback period = (System cost) divided by (Annual savings)
Example: If a 6kW system costs £11,000 and saves you £1,200 annually, your payback period is 11,000 divided by 1,200 = 9.2 years.
Since panels last 25+ years, you get 15+ years of free electricity after payback. A lower initial cost isn’t always better if it sacrifices efficiency or durability.
A £500 premium for higher-efficiency panels (20% vs 18%) might reduce payback time by 1 to 2 years. That’s a smart investment.
Warranty and Support
Warranties differ significantly between installers. Here’s what to compare:
Panel warranty (25 years standard) covers manufacturing defects and progressive power loss (typically 0.5% annually maximum).
Inverter warranty (10 to 12 years standard) covers inverter failure. Often you can extend this for £500 to £1,000.
Installation or workmanship warranty (10 years typical) covers installer errors and poor installation quality.
Compare warranty lengths carefully – longer is always better. A 12-year inverter warranty instead of 10 years provides genuine peace of mind.
Real-World Comparison Example
Let’s compare three scenarios for a typical 6kW system in Belfast:
Quote A (Budget): £9,500, 18% panel efficiency, estimated annual output 4,900 kWh, estimated annual savings £1,175, payback period 8.1 years, 25-year savings £21,000
Quote B (Mid-range): £11,200, 20% panel efficiency, estimated annual output 5,250 kWh, estimated annual savings £1,260, payback period 8.9 years, 25-year savings £23,400
Quote C (Premium): £13,000, 21% panel efficiency, estimated annual output 5,400 kWh, estimated annual savings £1,296, payback period 10.0 years, 25-year savings £23,300
Analysis: Quote B offers the best balance. The extra £1,700 upfront saves you money on energy over 25 years compared to Quote A. Quote C is expensive without enough additional benefit to justify the extra cost.
Solar Comparison Checklist
Use this when comparing solar quotes:
- System size: are all quotes for the same kW capacity?
- Panel brand and efficiency: Tier 1 or Tier 2 preferred
- Inverter type: string, micro or hybrid? Brand and warranty?
- Warranty: panel (25 years), inverter (10+ years), workmanship (10 years)
- Installation scope: what’s included versus charged separately?
- MCS and NICEIC accreditation: both present?
- Monitoring system: real-time app included?
- Building regulations: approval process and cost?
- Customer reviews: Google, Trustpilot, Which?
- Estimated annual output: kWh generation and cost savings
Common Mistakes When Comparing
Choosing only by price is the biggest mistake. The cheapest quote often cuts corners on quality, installer reliability or components. You pay the difference over 25 years through lower efficiency or maintenance costs.
Not comparing like-for-like systems creates confusion. You can’t compare a 5kW quote to a 6kW quote. Ensure quotes are identical in system size and components.
Ignoring the installer leaves you vulnerable. A reputable installer is as important as quality components. Poor installation compromises performance and creates warranty hassles.
Not calculating payback period means missing the bigger picture. Always compare long-term savings, not just upfront cost. A £2,000 premium that reduces payback time by 2 years is money well spent.
Getting Multiple Quotes
Get at least 3 quotes, ideally 5, from MCS-certified installers. This shows you price patterns and identifies outliers.
Ask each installer about their quality standards. How long have they been installing? What happens if something goes wrong? Do they stand behind their work?
Verify certifications and check reviews. MCS, NICEIC and Trustmark matter. Read at least 10 customer reviews on independent platforms before deciding.
Use this guide to calculate ROI yourself. Don’t just pick the cheapest. Pick the system with the best long-term value for your situation.
Ready to Compare?
You now know exactly what to look for when evaluating solar options for your Northern Ireland home. The next step is getting quotes from installers who meet these standards.
Instead of contacting multiple installers individually and coordinating everything yourself, we’ve already done the vetting work for you. We work exclusively with MCS-certified installers who meet the criteria outlined in this guide.
Fill out the form below to get connected with installers in your area. We’ll handle the comparison legwork so you can focus on making the right decision.