Solar Inverter Replacement in Wales
The inverter is the most likely component to fail on a solar PV system. While panels routinely last 25-30 years, most inverters have a typical service life of 10-12 years, and many will need replacement at least once during the lifetime of the system. The good news is that replacement is straightforward, relatively quick, and often substantially less expensive than the original installation.
Welsh Solar provides inverter replacement services across Wales for all major manufacturers, including SMA, Solis, GoodWe, Huawei, Fronius, SolarEdge, Growatt, and older brands no longer trading.
How to tell if your inverter is failing
Most inverter failures are signalled clearly on the inverter display or in the monitoring app — error codes, warning lights, or a simple "no power" status. Less obvious failures include reduced output (the inverter is working but not at full capacity), intermittent operation, or odd noises such as buzzing or whirring fans that did not previously run continuously.
A failing inverter often produces gradually declining generation over weeks or months before failing completely. If you monitor your system, you may notice the daily generation peak dropping by 10-20% even on bright days. This is a good early warning that the inverter is in trouble.
What replacement involves
Most inverter replacements are straightforward day jobs. We disconnect and isolate the existing inverter, remove it from the wall, fit the replacement, and reconnect the DC strings from the panels and the AC connection to your consumer unit. Commissioning, configuration, and testing typically take a couple of hours, after which the system is back generating.
Where the replacement inverter is from the same manufacturer and family as the original, the swap is usually direct. Where you are upgrading to a different brand — common when older inverters are no longer supported — there may be additional work to update DC isolators, monitoring equipment, or labelling, but this is usually modest.
- Same-brand replacement: usually direct swap
- Cross-brand replacement: minor additional work
- Hybrid inverter upgrade: enables battery addition
- String reconfiguration if increasing system size
- New monitoring platform if upgrading to smart inverter
- Updated MCS certification for new inverter
Typical costs and timescales
Replacement inverter costs vary widely with size and brand. A 3.6 kW single-phase replacement currently runs around £600-£900 for the unit itself, plus £200-£300 for installation and commissioning. Larger or three-phase inverters cost proportionately more, and hybrid inverters that integrate battery management cost £800-£1,500 for typical residential ratings.
Lead times for common inverter models are typically 1-2 weeks from order. We carry stock of the most popular residential models for faster turnaround. Emergency same-week service is sometimes possible for an additional charge.
Upgrading at the same time
Inverter replacement is often a good moment to consider upgrading the system. Modern hybrid inverters can manage battery storage as well as solar generation, which means a single replacement gives you a path to adding a battery later. Modern inverters also include better monitoring, smart-tariff integration, and EV charger compatibility that older units typically lack.
We always discuss upgrade options at the survey stage so you can make an informed choice between a like-for-like replacement and a strategic upgrade.
Frequently asked questions
How long do solar inverters typically last?
Most string inverters have a service life of 10-12 years. Higher-end inverters may last 15+. Microinverters and panel-level optimisers typically carry longer warranties (often 25 years) and last accordingly.
Should I replace with the same brand?
Where the original brand is still trading and supported, a direct same-brand replacement is usually simplest. Where the original brand has ceased trading, we typically replace with a current Tier 1 alternative.
Can I upgrade to a hybrid inverter?
Yes, this is one of the most popular upgrade choices. A hybrid inverter replacement gives you future battery-ready capability without further wiring changes.
Do you stock common inverters?
Yes, we carry stock of the most popular residential models for faster turnaround. Larger or specialist models typically have 1-2 week lead times.
Is my inverter still under warranty?
Standard inverter warranties are 5-12 years from installation date depending on brand and tier. Check your handover pack or contact the original installer if it is still trading. We can also check warranty status for many major brands.
Choosing the right replacement inverter
When an inverter needs replacing, the choice is usually between a like-for-like replacement (simplest, often cheapest) and a strategic upgrade that adds capabilities the original lacked. The most common upgrade paths are:
- String inverter to hybrid inverter: adds battery-ready capability for future battery installation. Adds £200-£400 to the unit cost.
- String inverter to inverter with panel-level monitoring: adds per-panel performance data, useful for diagnosing shading or panel-level issues.
- Old inverter with poor monitoring to modern unit with smart-tariff integration: works with time-of-use tariffs like Octopus Agile to optimise self-consumption.
- Three-phase inverter upgrade: if your system has grown beyond what the original single-phase unit can support, or you have moved to three-phase supply.
We discuss these options at quote stage and present the financial and practical case for each so you can choose what fits your circumstances.