When investing in a solar PV system, most homeowners focus on system size, savings and payback period. While these factors are important, an often forgotten and misunderstood factor is just as important: solar warranties.
Not all warranties are created equal. Understanding what is covered, for how long and by whom can make a significant difference to the long term value and reliability of your solar panels. This guide explains the three key types of solar warranty you should expect when installing solar in the South East.
Solar Panel Warranties Explained
Solar panels usually come with two separate warranties, both of which matter.
Product Warranty (Manufacturer Warranty)
The product warranty covers defects in materials or manufacturing faults. This typically ranges from 12-15 years for standard panels and 20-25 years for premium panels. If a panel fails due to a manufacturing issue, the manufacturer will replace or repair it under this warranty.
Performance Warranty
The performance warranty guarantees your solar panels will continue generating electricity above a stated output level over time. Most modern solar panels guarantee around 90-82% output after 10 years and 80-87% after 25 years. This ensures your solar PV system continues delivering long term savings rather than rapidly degrading.
Why This Matters
In the South East, where rooftops are ideal for solar generation, long term performance guarantees protect your return on investment for decades.
Inverter Warranties: The System’s Power Hub
The inverter is the heart of your solar PV system, converting the DC electricity generated by your panels into usable AC electricity for your home.
Standard Inverter Warranty
The warranty on your inverter is typically 5-10 years but can often be extended to 15years or more. As inverters work continuously and contain sensitive electronics, they are more likely to need replacement than panels over a system’s lifetime.
Optimisers and Smart Monitoring
Many modern systems include power optimisers and advanced monitoring, which often carry longer warranties than traditional string inverters. These systems also allow faster fault detection, improving system reliability.
Why This Matters
A longer inverter warranty reduces future costs and ensures consistent system performance – especially important in homes with partial shading or complex roof layouts common across the South East.
Workmanship Warranty: The Installer Guarantee
One of the most overlooked aspects of solar warranties is the workmanship warranty = the part that covers how the system is installed. This warranty is provided by the installer, not the manufacturer.
What a workmanship warranty covers
- Roof penetrations and mounting systems
- Electrical connections
- System design and installation errors
Typical workmanship warranties range from 2-5 years.
Why This Matters
Even the best solar panels can underperform if poorly installed. A strong workmanship warranty protects your roof, electrics and your peace of mind.
Manufacturer vs Installer Warranties: What’s the Difference?
| Warranty Type | Who Provides It | What It Covers |
| Panel Product Warranty | Manufacturer | Faulty or defective panels |
| Panel Performance Warranty | Manufacturer | Long-term energy output |
| Inverter Warranty | Manufacturer | Inverter and electronics |
| Workmanship Warranty | Installer | Installation quality and roof integrity |
A reliable solar PV system warranty package includes all four elements, clearly explained before installation begins.
What to Look for in a Solar Warranty
Before choosing a solar installer, make sure you ask:
- Are manufacturer warranties fully UK backed?
- Who handles warranty claims – the installer or manufacturer?
- Is labour included for replacements?
- Is monitoring included to identify faults quickly?
- Are warranties insurance backed?
Strong warranties reflect installer confidence and system quality.
Why SolarTherm UK Takes Warranties Seriously
At SolarTherm UK we design systems with long term performance and reliability in mind. Every installation is supported by:
- Tier one manufacturer warranties
- Proven inverter technology
- Clear workmanship guarantees
- Ongoing system support
We believe your solar PV system should deliver dependable savings, not unexpected surprises.
Thinking About Solar in the South East?
If you’re considering going solar and want clarity – not confusion – around warranties we’re here to help. A well-designed system with the right warranties will protect your home, your savings, and your investment for decades to come.
Contact SolarTherm UK today for a free, no obligation quote and design, tailored to your property, usage and future energy needs. No hard sell, just honest, expert advice.
Your home. Your energy. Your future.
