Solar Panel Optimisers UK: Tigo vs SolarEdge vs Microinverters (2026)

Solar panel optimisers sit behind each panel and let it produce power independently from the rest of the string. If one panel is shaded or dirty, the others keep working at full output instead of being dragged down. But optimisers are not the only way to achieve this. Microinverters do the same job and more. This guide compares all three approaches honestly so you can decide what fits your roof.

A note on this article: I am a DIY homeowner with a Tigo installation since May 2023 on a north-west facing string with intermittent shading. That gives me hands-on experience with one product, not all of them. I have tried to present the data fairly, but my perspective is limited. Get quotes and opinions from multiple installers before committing.

Three Approaches to Panel-Level Optimisation

There are three ways to give each panel independence from the rest of the string. Each has trade-offs.

Tigo vs SolarEdge: Side-by-Side

Prices are approximate UK retail figures as of early 2026 and will vary by supplier, quantity, and installer margins. Check current wholesaler pricing on sites like SegenSolar or CED Greentech, and always get multiple quotes.

Tigo Optimisers

Tigo’s main advantage is inverter independence. They clip onto the back of any panel and work with any string or hybrid inverter, making them the only practical option for retrofitting optimisers to an existing system.

Selective deployment: Unlike SolarEdge (which requires an optimiser on every panel in the string), Tigo optimisers can be fitted only to the panels that actually suffer from shading. If you have a 10-panel array but only two panels are affected by a chimney shadow, you buy two Tigo units (£70-100) rather than ten. This is Tigo’s biggest cost advantage and one that most comparison articles miss.

Tigo’s own global dataset of 105,000 sites across 122 countries reports an average 8.7% energy gain from mismatch loss recovery (Tigo, 2024). Their Photon test results show:

Downsides: Panel-level monitoring requires the CCA hub (~£150 extra). Without it, the optimisers work but you cannot see individual panel data. Some users in forums report additional subscription or API access limitations for full historical data.

SolarEdge Optimisers

SolarEdge optimisers are tightly integrated with SolarEdge inverters. You get panel-level monitoring out of the box with no extra hardware, and built-in SafeDC shutdown reduces string voltage when the inverter is off — a genuine safety advantage for installers and firefighters.

SolarEdge’s PV Performance white paper reports:

Note that SolarEdge reports a significantly higher gain under horizontal shading (34.6% vs Tigo’s 20.8%). This matters if your roof has obstructions like dormers, chimneys, or nearby buildings that cast wide horizontal shadows.

A note on the data: Both manufacturers report identical figures for no-shading (1.5-1.7%) and pole shade (9.7%). These come from different white papers using different test setups, so the coincidence is worth flagging. Both sets of figures are manufacturer-sourced and should be treated as indicative rather than guaranteed. The independent research section below provides a more balanced picture.

Downsides: Only works with SolarEdge inverters. If you have a Sunsynk, Solis, Growatt, or any other brand, SolarEdge optimisers are not an option. Some installer forums note that strings with many heavily shaded panels can cause string voltage issues on SolarEdge systems, though this is an edge case. Worth noting: Huawei also offers optimisers (SUN2000-P series) for their own hybrid inverters, with a small but growing UK presence — a third proprietary ecosystem to consider if you are already buying Huawei hardware.

What About Microinverters?

This article originally compared only Tigo and SolarEdge, but that misses a major option. Microinverters (Enphase IQ8 series, Hoymiles HMS/HMT, APSystems) convert DC to AC at each panel individually. There is no DC string at all.

For the exact use cases where optimisers shine — complex roofs, heavy shading, mixed orientations — microinverters often perform as well or better. Independent tests and YouTube comparisons (search “Enphase vs SolarEdge shading test”) consistently show microinverters matching or exceeding optimiser setups under variable shade, because each panel operates completely independently with no string voltage constraints.

Advantages over optimisers:

• No single point of failure (no central inverter to go down)
• Each panel is fully independent — no string voltage issues even under heavy shade
• Safer: no high-voltage DC on the roof at all
• Easier to expand one panel at a time
• Better outage resilience with compatible batteries (Enphase IQ Battery)

Disadvantages:

• Higher cost per panel (typically £80-120 per microinverter vs £35-55 per optimiser)
• More components on the roof means more potential failure points over 25 years
• Cannot retrofit to an existing string inverter setup (you replace the inverter entirely)
• Battery integration is brand-specific (Enphase works best with Enphase batteries)

If you are designing a new system from scratch and have a complex roof, get quotes for both an optimiser-based string setup and a microinverter system. The price gap has narrowed significantly since 2024, and for heavily shaded or multi-orientation roofs, microinverters can be the better long-term investment. For a deeper look at how inverter types compare, see the inverter guide.

What Does Independent Research Say?

The manufacturer data above is useful but inherently promotional. Here is what independent studies found.

A study by the University of Southern Denmark tested both SolarEdge and Tigo optimisers and confirmed that they improve output under shading conditions. However, the study also found that in completely unshaded, uniform conditions, optimisers can slightly reduce total output due to their own power consumption. This is not a minor footnote — it means that on a clean, unshaded south-facing roof, adding optimisers may cost you energy rather than gain it. The 1.5-1.7% “gain” reported by manufacturers in unshaded conditions should be treated with scepticism.

NREL field data shows gains of 3-4.5% under light shading, 15-18% under moderate shading, and 18-22% under heavy shading compared to a plain string inverter. A 2019 paper from the University of Campinas found a general positive effect across conditions, arguing that real-world panel mismatch (from manufacturing tolerances, ageing differences, and thermal variation) means strings rarely run at truly uniform output.

There is also a scenario where neither optimisers nor microinverters are necessary even with shade. Most modern solar panels have built-in bypass diodes that allow current to route around a completely shaded cell group. If you have thick, persistent shade covering entire panels (for example a large tree canopy across half your array), the bypass diodes already handle this at no extra cost. Optimisers add value when shade is partial or intermittent — a chimney shadow that moves across one or two panels during the day, or a vent pipe that shades a few cells on an otherwise productive panel. That is the mismatch scenario where the rest of the string gets dragged down and an optimiser can recover the lost output.

The honest takeaway: if your shade is partial and intermittent, optimisers or microinverters will measurably help. If your panels are heavily and persistently shaded, bypass diodes already handle it. If your roof is clean and unshaded, the money is probably better spent on an extra panel or a battery.

Reliability

Optimisers add a component to every panel, so reliability matters. Industry data generally shows very low early failure rates for optimisers — lower than string inverters, though exact numbers vary by study and year. Both Tigo and SolarEdge offer 25-year warranties. In practice, failures do happen and warranty claims can take time, so factor in the practicality of accessing roof-mounted components if a single unit fails years down the line.

What Do Optimisers Add to the Cost?

The cost depends on which system you choose. SolarEdge requires an optimiser on every panel in the string, so a 10-panel install means 10 units at £40-55 each (£400-550). Tigo allows selective deployment — if only 2-3 panels are shaded, you only buy 2-3 units (£70-150 total). Whether that pays back depends entirely on how much shading your roof gets. On a fully unshaded south-facing roof, the gains are marginal and may not justify the cost. On a partially shaded or multi-orientation roof, the case is much stronger — particularly if the alternative is losing 15-25% of a panel’s output to string-level mismatch.

My Experience With Tigo

I installed Tigo TS4-A-O optimisers on a north-west facing string with intermittent shading from a neighbouring building in May 2023. They have worked reliably for nearly three years. I chose Tigo because I already had a Sunsynk inverter and SolarEdge was not an option.

I cannot speak to SolarEdge or Enphase from personal experience. If I were building a new system today on a complex roof, I would seriously consider microinverters — the price gap has narrowed and the full panel independence is appealing. For a straightforward retrofit where you want to reclaim shading losses on an existing string, Tigo remains the practical choice because nothing else works with a non-SolarEdge inverter.

Which Should You Choose?

• Retrofitting an existing system: Tigo. It is the only optimiser that works with any inverter brand.
• New install with a SolarEdge inverter: SolarEdge optimisers. Built-in monitoring and SafeDC make the most of the ecosystem.
• New install on a complex or heavily shaded roof: Get quotes for both Tigo + string inverter and Enphase/Hoymiles microinverters. Compare total system cost and projected output.
• Clean, unshaded south-facing roof: Consider skipping optimisers entirely. The gains may not justify the cost — spend the money on an extra panel or a battery instead.

For a broader look at how optimisers fit into a system, see the guide to solar panel optimisers and the inverter comparison.

Nikola Nedoklanov

UK-based solar DIY enthusiast with 5+ years hands-on experience.

About the author

Published: April 1, 2026

Last updated: April 1, 2026