The short version
- A linear performance warranty specifies how a panel's energy output will degrade over time.
- Common degradation rates range from 0.3% to 0.8% a year; lower means slower efficiency loss.
- Warranties often run for 25 to 30 years.
- Keep records of installation, maintenance and performance data in case you need to claim.
Solar panels have become an increasingly popular choice for homeowners and businesses looking to harness clean, renewable energy.
When considering solar panel options, you’ll likely come across the term “linear performance warranty”. But what exactly does it mean, and how does it affect your solar panel investment?
What is a linear performance warranty?
A linear performance warranty is a guarantee offered by solar panel manufacturers that specifies how the energy output of their panels will degrade over time. It assures customers that the panels will maintain a certain level of efficiency for a predefined period.
This warranty is essential because it gives you a clear understanding of how your solar panels will perform throughout their lifespan.
Key elements of a linear performance warranty
- Degradation rate: manufacturers typically specify a degradation rate, usually expressed as a percentage. This shows how much the panel’s efficiency will decrease each year. Common degradation rates range from 0.3% to 0.8%. A lower degradation rate means slower efficiency loss.
- Warranty duration: the linear performance warranty usually covers a specific number of years, often 25 to 30 years. Check the warranty duration for the panels you’re considering.
Your solar panels will maintain a certain level of efficiency over the years, so your investment in solar energy continues to pay off.
Knowing how your panels will perform over time lets you predict the savings and energy production of your system more accurately.
Solar panels are a significant investment, and the warranty helps protect it by offering cover for an extended period.
Tips for evaluating linear performance warranties:
- Look for panels with lower degradation rates, as they maintain efficiency better over time, and compare the rates offered by different manufacturers.
- Choose panels from well-established, reputable manufacturers known for honouring their warranties.
- Keep a record of your installation, maintenance and performance data. This will be valuable if you ever need to make a warranty claim.
Making an informed choice
Understanding linear performance warranties gives you a clear picture of how your panels will perform over time, helping you make an informed decision and protect your solar investment.
When you choose panels with Solar Select, we’ll advise you of the degradation rate and warranty duration so you can pick panels that best suit your energy needs and long-term goals, and enjoy clean, renewable energy for decades to come.
Published .
Written by
Terry Hayward
Managing Director, Solar Select
Terry leads Solar Select, the family-run solar and battery installer in Droitwich. The business started in 2011 with a man and a van, and is now a team of local engineers, sales, admin and support staff.
Checked by Jack Gartshore, Solar Electrical Engineer.About Solar Select
- MCS-certified installer, fitting solar and batteries locally since 2011
- Rated 5.0 from 33 reviews on Google and 10/10 on Checkatrade
- Written by our own team and checked by one of our engineers
How we write our articles: every guide is written by the Solar Select team from what we see on real installs, checked by a qualified engineer, and reviewed when tariffs or rules change. Spotted something out of date? Email info@solarselect.net. Solar Select Limited, Salwarpe Business Park, Droitwich WR9 9BN. Company No. 10335489. Our accreditations.
