Complete DIY Solar Panel Installation Guide for UK Homes
Installing your own solar panels can save you £5,000 to £10,000 compared to hiring an installer. But it's not a weekend project — you need to understand the regs, plan carefully, and be comfortable working on a roof.
This guide walks through the entire process for a standard UK domestic installation. We assume a typical 4kW system (10–12 panels) on a pitched roof — the sweet spot for most 3-bed homes.
Can You Legally DIY Solar in the UK?
Yes — but with caveats. There's no law saying only MCS-certified installers can fit panels. However:
- The final electrical connection must be signed off by a Part P qualified electrician
- Grid connection (G98/G99) must be approved by your Distribution Network Operator (DNO)
- Building Regulations apply — the roof must be structurally sound for the extra weight
- Planning permission is rarely needed for domestic solar (permitted development), but check if you're in a conservation area or listed building
- MCS certification is not required for DIY, but you need it to access SEG payments (Smart Export Guarantee). A workaround: pay an MCS electrician to do the final sign-off
Step 1: Assess Your Roof
Direction and Pitch
South-facing is ideal, but east/west splits work well with modern panels. North-facing is usually not worth it in the UK. A pitch of 30–40° is optimal. Flat roofs need tilted mounting frames.
Shading
Walk around your property at different times of day. Chimneys, trees, and neighbouring buildings can cast shadows. Even partial shading on one panel can drag down a whole string if you're not using optimisers or microinverters.
Structural Check
A typical 4kW system adds roughly 250–300kg to your roof, spread across multiple mounting points. Most UK roofs built after 1970 can handle this, but if your roof is older or showing signs of sagging, get a structural engineer's opinion before ordering panels.
Step 2: Size Your System
Work backwards from your annual electricity usage. Check your bill for kWh/year. A typical UK home uses 2,700–3,600 kWh/year. A 4kW system in the UK generates roughly 3,400–3,800 kWh/year — enough to cover most of a typical home's usage (though not all at the time you need it).
Rough sizing:
| Annual Usage | Recommended System | Panels (400W) |
|---|---|---|
| 2,000 kWh | 2.4 kW | 6 |
| 3,000 kWh | 3.6 kW | 9 |
| 4,000 kWh | 4.8 kW | 12 |
| 5,000+ kWh | 6.0 kW+ | 15+ |
Use our solar savings calculator for a personalised estimate based on your postcode and usage.
Step 3: Choose Your Equipment
Solar Panels
For DIY, stick to standard 60-cell or 120-half-cell monocrystalline panels in the 400–440W range. They're the sweet spot for price, efficiency, and handling weight (~21kg each). Brands to consider: JA Solar, Longi, Canadian Solar, Jinko. Expect to pay £80–130 per panel. Browse solar panels on Amazon →
Inverter
The inverter converts DC from your panels to AC for your home. Options:
- String inverter — cheapest, one central unit. Good if you have no shading. (£400–800)
- String + optimisers — small devices per panel to handle shading. (£200–400 extra)
- Microinverters — one per panel, best for complex roofs with shading. Most expensive. (£80–150 per panel)
Popular UK models: Solis, Growatt, SMA, SolarEdge. Compare inverters on Amazon →
Mounting System
You need roof hooks, aluminium rails, and clamps. Systems are roof-type specific (tile, slate, metal). Companies like Renusol, K2 Systems, and Van der Valk make kits for UK roofs. Expect £300–500.
Cables and Isolators
You need 4mm² or 6mm² DC solar cable (double-insulated), MC4 connectors, a DC isolator, an AC isolator, and standard T&E cable from the inverter to your consumer unit. Budget £150–250.
Step 4: Notify Your DNO
Before you connect anything, you must notify your Distribution Network Operator. For systems under 3.68kW (16A per phase), you use the G98 form — it's a simple notification, install then inform. For systems 3.68kW and above, you need G99 pre-approval — they can take 4–6 weeks to respond, so apply early.
Find your DNO at energynetworks.org.
Step 5: Mount the Rails
- Mark out rafter positions (use a stud finder or tap and listen)
- Lift tiles carefully — slide them up, don't crack them
- Fix roof hooks to rafters with appropriate screws (usually 8mm coach screws)
- Flash around hooks with lead or aluminium flashing to maintain waterproofing
- Attach aluminium rails to hooks, ensuring they're level
Safety: Use roof ladders, a harness, and don't work alone. Most DIY solar injuries are falls.
Step 6: Fit the Panels
- Lift panels onto the roof one at a time (two people for this)
- Clamp them to the rails — end clamps for outer panels, mid clamps between them
- Check they're secure and there's a 50–100mm gap under them for airflow
- Connect MC4 cables between panels before connecting to the inverter — the DC voltage builds up fast
Step 7: Wire the Inverter
This is the part where you need an electrician. Even if you physically mount the inverter and run cables, the final connection to your consumer unit must be done by a Part P qualified spark.
The rough sequence:
- Mount inverter on a solid wall near your consumer unit (garage, utility room)
- Run DC cables from panels through the roof and down to the inverter location
- Install DC isolator near the inverter
- Electrician connects AC side to a dedicated MCB in your consumer unit
- Electrician tests and signs off
Step 8: Commissioning
- Switch on DC isolator first, then AC
- Inverter should power up and start scanning for the grid
- Configure country settings to UK G98/G99
- Monitor for a full day — check production matches expectations
Total DIY Cost vs Installer
| Component | DIY Cost | Installer Cost |
|---|---|---|
| 10× 400W panels | £900–1,300 | £2,000–2,500 |
| Inverter (5kW) | £500–800 | £800–1,200 |
| Mounting system | £300–500 | £500–800 |
| Cables & isolators | £150–250 | £250–400 |
| Electrician sign-off | £200–400 | Included |
| Scaffolding (if needed) | £500–800 | Included |
| Total | £2,550–4,050 | £5,000–9,000 |
Saving: £2,500–5,000 minimum. If you can avoid scaffolding (bungalow or dormer access), save even more.
Common Mistakes to Avoid
- Not notifying the DNO — they can force you to disconnect
- Undersizing cables — voltage drop kills efficiency over long DC runs
- Mixing panel orientations on the same string — they'll all perform at the weakest panel's level
- Ignoring ventilation — panels lose ~0.3% efficiency per °C above 25°C
- Skipping the electrician — your home insurance is void if there's an electrical fire from un-certified work
Is DIY Solar Worth It?
If you're comfortable with physical work, can follow electrical diagrams, and have a straightforward roof: yes, absolutely. You'll save thousands and learn a valuable skill. If your roof is steep, three storeys up, or you're not confident with tools: hire someone.
Next: Use our calculator to see your payback period →
Frequently asked questions
Can you legally install solar panels yourself in the UK?
Yes. No law requires an MCS-certified installer to fit panels, but the final electrical connection must be signed off by a Part P qualified electrician, you must notify your DNO via a G98 or G99 form, and the work must meet Building Regulations. MCS certification is only needed to claim Smart Export Guarantee payments.
How much can you save installing solar yourself?
A DIY 4kW system typically costs £2,550–£4,050 in materials plus electrician sign-off, versus £5,000–£9,000 from an installer — a saving of at least £2,500–£5,000, more if you can avoid scaffolding.
Do I need to notify the DNO before installing solar?
Yes. For systems under 3.68kW per phase you submit a G98 notification (install then inform). For 3.68kW and above you need G99 pre-approval, which can take 4–6 weeks, so apply early.
Does DIY solar still need an electrician?
Yes. You can do the mounting, panel fitting and cable runs, but the final AC connection to your consumer unit must be made and certified by a Part P qualified electrician. Skipping this can void your home insurance.