Best Solar Power Inverters

Introduction

A solar inverter is the component that converts the DC power generated by your solar panels into AC power suitable for use in your home and for export to the national grid. It is the most complex component in a solar system and, over a 25-year system lifetime, the one most likely to need replacing, so choosing the right one matters.

This guide covers the best inverters available in the UK market, what to look for when choosing, and which brands we recommend for different types of installation.

If you are installing solar with battery storage, you will also want to read our hybrid inverter page, most modern battery systems use a hybrid inverter rather than a standard string inverter, and the choice of inverter and battery are closely linked.

Our inverter recommendations at a glance

For most domestic solar-only installations, we recommend Solis as our standard inverter, reliable, well-supported in the UK, and excellent value. For customers wanting a premium option, Fronius is our choice: one of the best-built and best-supported inverters on the market. Where shading is a factor, SolarEdge is the clear answer.

The full comparison table and brand-by-brand detail is set out below.

Solis

Solis, made by Chinese manufacturer Ginlong Technologies, is one of the most widely installed inverter brands in the UK and globally. It sits in the mid-market on price but punches above its weight on reliability and features. The monitoring platform, the Ginlong portal, is straightforward and gives a clear view of system performance. Warranty is 5 years as standard, extendable to 10 years.

For most domestic solar installations, Solis represents the best combination of quality, reliability and value available. It is our standard recommendation.

Fronius

Fronius are an Austrian manufacturer with a decades-long track record in solar inverters and a reputation that consistently ranks among the best in the industry. The Fronius Primo is their flagship single-phase residential inverter, covering outputs from 1.5kW to 15kW, and it is regularly voted the top choice among professional installers for build quality and after-sales support.

Fronius inverters are more expensive than mid-market alternatives, but that premium buys you a notably lower failure rate, an excellent monitoring platform in Solar.web, and a support network that is responsive and well-established in the UK. Warranty is 5 years standard, extendable to 10 years free on registration.

For customers where long-term reliability and support are the priority, Fronius is our recommendation.

SolarEdge

SolarEdge takes a fundamentally different approach to most inverters. Rather than optimising the output of the array as a whole — which means performance is pulled down by the weakest panel, SolarEdge uses a power optimiser attached to each individual panel, allowing every panel to perform at its own maximum regardless of what the others are doing.

The practical result is that shading, soiling, or panels in different orientations have far less impact on total system output than they would with a standard string inverter. SolarEdge also provides panel-level monitoring, which makes it much easier to identify and diagnose faults.

The trade-off is cost, the power optimisers add to the upfront price of the system, and every panel requires one. SolarEdge will typically add around 10% to the overall system cost, but on a shaded or complex roof can add up to 25% to lifetime output. The warranty is also notably strong: 12 years on the inverter as standard, and 25 years on the power optimisers.

For straightforward unshaded roofs, SolarEdge is not necessary and the cost premium is hard to justify. For complex roofs, it is often worth it.

SMA

SMA are a German manufacturer and one of the longest-established names in the solar inverter market, founded in 1981. Their Sunny Boy range has been a benchmark for quality for many years. Efficiency on current models is 97.5%, warranty is 5 years standard extendable to 10 years on registration.

SMA sit at the premium end of the market alongside Fronius. For most domestic installations we would lean towards Fronius or Solis, but SMA remains a highly respected brand and a solid choice for customers who specifically request it.

SolaX

SolaX are a Chinese manufacturer with a strong hybrid inverter range, making them particularly relevant for solar-plus-storage installations. Their standard inverters cover 0.7–8kW with a notably strong warranty, 10 years as standard, extendable to 20 years. Efficiency is up to 97.8%.

Growatt

Growatt are another well-established Chinese manufacturer occupying a similar space to Solis, competitive on price, reliable in the field, and widely installed in the UK. Monitoring is via the ShinePhone app or ShineServer browser portal. Warranty is 5 years standard, extendable to 10 years. A solid choice for budget-conscious installations.

Victron

Victron are a Dutch manufacturer occupying a distinct niche: their inverters are highly configurable and can handle DC-coupled solar, AC-coupled solar, battery storage, and generator input in combination, making them the go-to choice for off-grid systems, complex three-phase setups, and installations that fall outside the scope of standard residential inverters. Monitoring is available via app, the Victron Energy Portal, and locally via a GX Touch display. Warranty is 5 years standard, extendable to 10 years.

Inverter type

For most domestic roofs, a standard string inverter is the right choice. The array is optimised as a whole, which works well when panels are unshaded and in broadly the same orientation. Where shading is a factor, SolarEdge is the recommended alternative.

For installations that include battery storage, a hybrid inverter is almost always the better route. See our hybrid inverter page for more detail.

Quality and reliability

A typical inverter can be expected to last 12–14 years, meaning one replacement over a 25-year system lifetime is normal. Industry estimates suggest around 2–6% of inverters fail within the first 10 years.

The most common causes of failure are:

• Inadequate ventilation. Inverters installed in hot lofts or enclosed spaces will overheat. A free flow of air around the unit is essential.
• Incorrect specification. Under- or over-sizing causes the inverter to run outside its design parameters, generating excess heat.
• Poor installation. Incorrect cabling, connections, or programming.
• Over-voltage. High grid voltages, which are not uncommon in parts of the UK, can repeatedly stress internal components over time. If over-voltage is a persistent issue, your DNO has a legal obligation to address it.
• Water or dust ingress. Humid or dusty environments accelerate failure.

Warranty and manufacturer support

For most domestic inverters, 10 years is the effective standard, either as the base warranty or via a free extension on registration. Always check the conditions carefully, as installation outside manufacturer guidelines can void the warranty.

At Spirit, our domestic installations are covered by a five-year workmanship warranty, and we handle any manufacturer liaison during that period on your behalf.

Monitoring

All the inverters we install include monitoring via an app or online portal. At the basic level this shows daily and cumulative generation, useful for checking the system is performing as expected and for timing high-consumption appliances (washing machines, dishwashers, EV chargers) to coincide with peak solar output. SolarEdge goes further, providing panel-level data that makes it much easier to identify where losses are occurring on more complex systems.

Efficiency

Modern inverters typically convert 97–99% of DC input into usable AC output, with the remaining 1–3% consumed by the inverter itself. When comparing models, look at the Euro efficiency figure on the datasheet rather than peak efficiency, it is a weighted average across realistic European irradiance conditions and is a more accurate reflection of real-world performance.

G98/G99 and export limitation

Grid-tied inverters in the UK must comply with G98 (systems up to 3.68kW) or G99 (systems over 3.68kW). For systems under 3.68kW, DNO notification is handled retroactively. For systems over 3.68kW, we apply for permission on your behalf, this can take up to three months.

Where the local grid cannot accommodate full export, export limitation caps the power sent to the grid at a set threshold. The best inverters handle this proportionally, reducing output to just below the limit rather than shutting down entirely, so you can still generate and export up to the threshold and continue to benefit from your export tariff. Fronius handles export limitation this way.

Battery systems with backup capability require DNO permission, which now applies to most batteries. We recommend applying for a higher permission level than you currently need to allow for future expansion.