Solar prices by system size
Compare 3kW, 4kW and 6kW side by side, with or without a battery. Then use the checklist to read your quotes line by line.
Compare 3kW, 4kW and 6kW at a glance
Swipe sideways to see every size
| 3kW | 4kW | 6kW | With battery | |
|---|---|---|---|---|
| Panels | 7 or 8 panels | 9 or 10 panels | 14 or 15 panels | Any size here, plus a battery |
| Space | around 15m² of clear roof | around 20m² of clear roof | around 30m², often over two roof faces | Plus a spot for the battery: garage, utility room or outside wall |
| Often suits | Terraces, smaller semis and dormer bungalows | The typical 1930s semi with one good roof face | Detached homes and bigger or split roofs | Homes out in the day, or on a cheap overnight rate |
| Birmingham range | Being gathered | Being gathered | Being gathered | Being gathered |
| Request quotes | Get quotes | Get quotes | Get quotes | Get quotes |
Panel counts and space assume panels of about 400 to 450W, each about 1.7m by 1.1m. The installer's survey sets the real layout. Birmingham ranges: we'll add dated price ranges once we hold enough real quotes for West Midlands homes. No figure beats a made-up one.
Add a battery: what changes
| Panels only | Panels and battery | |
|---|---|---|
| Daytime | Your home uses the solar first | Your home uses the solar first |
| Spare daytime power | Goes to the grid | Charges the battery first |
| Evenings | From the grid | From the battery until it runs low |
| Cheaper overnight rates | No change | The battery can charge overnight |
| Space | Roof only | Roof, plus a spot for the battery |
| On the quote | Panels, inverter, scaffold, fitting | All of that, plus the battery and often a hybrid inverter |
6 things that move the price
- System size. More panels cost more in total, but often less per panel.
- Scaffold. Two-storey bays, conservatories and hillside streets need more of it.
- Roof shape. Hips, dormers, chimney stacks and rear wings cut usable space and add fitting time.
- Panels and inverter. All-black or higher-output panels, and hybrid inverters, cost more.
- A battery. Usually the biggest single extra. Compare batteries by usable kWh.
- Electrics. An older fuse box or a long cable run to the inverter adds work.
Check a quote line by line
Lay your quotes side by side. Each one should show:
- System size in kW, the number of panels, and the panel make and model
- The inverter make and model, and whether it can take a battery later
- Battery size in usable kWh, if there is one
- Scaffold, fitting, electrics and any bird protection, each listed
- Expected yearly generation, and how they worked it out
- Who tells the network operator (National Grid Electricity Distribution in the West Midlands)
- Warranties on panels, inverter, battery and the work, and who stands behind each
- The certification scheme the installer belongs to. Check it on the scheme's own website.
- The total including VAT, the deposit, and when the rest is due
Why don't you show prices yet?
We don't yet hold enough real Birmingham quotes to give an honest range. Prices swing with scaffold, roof shape and kit. When we do, the ranges go in the table with the date they were checked.
Is a bigger system always better?
Not always. The sweet spot is a size that fits your roof and the way you use power. Bigger systems often cost less per panel, so get both sizes quoted if you're torn.
Does a 6kW system need the network operator's approval?
Larger systems can need approval from National Grid Electricity Distribution before fitting, rather than a notice afterwards. Your installer applies for you and should tell you if it affects the timing.