How Long Do Commercial Solar Panels Last? Lifespan, Warranties and Recycling

How long commercial solar panels last

RC62 says the PV system itself may not change over its 25 to 35 year life expectancy, but that trees, lichen, nesting birds, new buildings and more extreme weather around it can change how it performs and add risk (RC62). The Church of England's guidance says the warrantied lifespan of a solar panel tends to be between 20 and 30 years, and advises doing any major roof repairs before installing if the roof would need them within that time (Church of England).

• Plan the roof first. If the roof needs replacing within the panels' life, do it before installing, or in the same scaffold
• Lease length. On a rented building, the lease should outlast the system's life or deal with it at the end
• Keep it maintained. Inspection, cleaning and monitoring keep output up and risk down

See solar maintenance and solar on leased property.

Degradation: what the warranties say

Panels produce slightly less each year. Rather than rely on a general figure, read the performance warranty for the panels you are offered: it states the minimum share of the original output the manufacturer guarantees after a set number of years. Ask the installer which figure their generation estimate and payback assume, and whether the proposal's savings allow for it. See how much electricity solar produces and payback.

Inverters and other parts

The panels are usually the longest-lived part. Inverters, isolators and connectors work harder and wear sooner: RC62 cites a 2017 BRE study that found DC connectors, inverters and DC isolators accounted for 84% of PV system related fires, and recommends live monitoring to catch faults early (RC62). Ask how long the inverter warranty runs, whether it can be extended, and budget for at least one inverter replacement over the life of the system.

Warranties: product, performance and workmanship

On the roof, the MCS installation standard says that where the existing roof covering is under warranty, the roof warranty provider should be consulted to establish whether the installation will invalidate it (MIS 3002, 3.9.2). Our guide to choosing an installer covers comparing proposals.

Recycling at end of life

GOV.UK says all PV panels are electrical and electronic equipment under the WEEE Regulations, in category 14, and that because they are of a generic size and design they "must be reported as household (B2C) regardless of where they're installed", including on commercial premises and in solar farms (GOV.UK). In practice, panels removed at the end of their life go through the WEEE collection and treatment system, not general waste. Ask the installer how they handle removal and recycling, and include it in any decommissioning plan or roof lease.