Solar Inverter Buyer's Guide (UK 2026)
The inverter is the brain of a solar system: it converts the DC your panels produce into the AC your home uses, manages grid export, and, on hybrid models, charges a battery. Get it wrong and you throttle a good array or fail your DNO connection. This guide covers the three types, how to size one, and the best models on sale in the UK in 2026.
Which type is right for your roof?
Pros
- Cheapest option (£400-800)
- Highest efficiency, fewer conversion stages
- Easy to service, one unit at ground level
- Simple wiring, panels in one series string
Cons
- Whole string drops if one panel is shaded
- No per-panel monitoring
- High-voltage DC on the roof
- Can't mix orientations on the same string
Pros
- Every panel operates independently
- Per-panel monitoring via app
- No high-voltage DC on the roof
- Easy to expand, one at a time
Cons
- Most expensive per watt (£80-150/panel)
- More connectors to fail on the roof
- Harder to service (on the roof)
- Slightly lower efficiency than string
Pros
- Manages solar AND battery in one unit
- Can charge battery from cheap overnight grid
- Future-proof, add battery later
- DC-coupled, highest round-trip efficiency
Cons
- More expensive upfront (£700-1,400)
- Needs battery to justify the premium
- More complex commissioning
- Battery compatibility varies by brand
Have shading but want string pricing? Add DC optimisers (e.g. SolarEdge, Tigo) -- small per-panel devices that give you microinverter-style shade tolerance and monitoring while keeping a central inverter.
Best solar inverters compared (UK 2026)
Tap any column heading to sort. ★ marks our pick in each type.
| Model | Type | Power | Approx price | Warranty | Best for |
|---|---|---|---|---|---|
| Solis S6 5G | String | 3.6 kW | £450-650 | 5 yr | Simple unshaded roof |
| Growatt MIN 3600TL-X | String | 3.6 kW | £420-600 | 10 yr | Budget grid-tie |
| Sunsynk 5.5kW Hybrid | Hybrid | 5.5 kW | £1,050-1,350 | 10 yr | Solar + battery |
| GivEnergy 5.0 Hybrid | Hybrid | 5.0 kW | £1,100-1,400 | 12 yr | UK support + battery |
| Enphase IQ8 (per panel) | Micro | 384 W | £110-150 | 15 yr | Shaded / complex roof |
| SMA Sunny Boy 4.0 | String | 4.0 kW | £700-900 | 5 yr | Premium reliability |
Compare current inverter prices on Amazon →
🛒 Where to buy these inverters
Prices checked live on Amazon UK. DIY Solar UK earns from qualifying purchases.
Browse full inverter range at Sunstore Solar
Sunstore stocks Solis, Growatt, Sunsynk and GivEnergy at trade prices with UK warranty.
Shop Sunstore inverters →How to size an inverter
Match the inverter to your array's peak DC power (kWp), not your battery or your usage. The array-to-inverter ratio should sit between roughly 1.0 and 1.25:
| Array size | Inverter size | Notes |
|---|---|---|
| 3.0 kWp | 2.5-3.0 kW | Under 3.68kW → G98 notification |
| 4.0 kWp | 3.6-4.0 kW | Most common 3-bed setup |
| 5.0 kWp | 4.0-5.0 kW | G99 pre-approval usually needed |
| 6.0 kWp | 5.0-6.0 kW | Consider a hybrid for future battery |
Mild undersizing is normal in the UK: our panels rarely hit their rated output, so a slightly smaller inverter runs closer to its efficient range and clips only a handful of peak-summer hours. Don't oversize "to be safe" -- it just costs more and runs less efficiently in low light.
The must-check: UK grid-code certification
For any grid-connected system the inverter must hold a valid G98 or G99 compliance certificate and appear on the Energy Networks Association type-test register. Your DNO can refuse connection for a non-compliant unit. All the models above are certified; the risk is with cheap unbranded inverters. See the installation guide for the full DNO notification process.
Not sure what size system to build?
Our calculator sizes the array (and therefore the inverter) against your electricity bill.
Open the solar calculator →Frequently asked questions
What size inverter do I need for my solar panels?
Size the inverter between about 80% and 105% of your array's peak DC power. A 4kWp array pairs well with a 3.6-4kW inverter. Slight undersizing (a ratio up to ~1.25) is normal in the UK because panels rarely hit rated output, and it improves low-light efficiency.
Should I get a string inverter or microinverters?
Choose a string inverter for a simple, unshaded roof on one or two planes -- cheapest and most efficient. Choose microinverters (or add DC optimisers) if you have shading, multiple orientations, or want per-panel monitoring and safety.
What is a hybrid inverter?
A hybrid inverter can charge and discharge a battery as well as convert solar DC to AC. It's the best choice if you plan to add battery storage now or later, and it can charge the battery from cheap overnight grid electricity on a time-of-use tariff.
Does the inverter need to be certified for the UK grid?
Yes. For any grid-connected system the inverter must hold a valid G98 or G99 grid-code certificate and be listed on the ENA type-test register. Your DNO can refuse connection for a non-compliant inverter, so check before you buy.