Hidden Solar Installation Costs Nobody Tells You About

The headline price on a solar quote rarely tells the full story. Between scaffolding extras, consumer unit upgrades, and bird proofing, the actual cost of going solar can be £1,000–£2,500 more than the number you first see. Here's every hidden cost you should know about before you sign anything.

1. Scaffolding (£300–£600)

Most solar quotes include basic scaffolding for a standard two-storey house with straightforward roof access. But "basic" is doing a lot of heavy lifting in that sentence.

If your roof has complex access — multiple levels, a dormer, chimneys that need working around, or a conservatory below — scaffolding costs more. A three-storey property or one on a steep slope can push scaffolding to £800 or more.

What to ask: "Is scaffolding included in the quote, and does that cover my specific roof access?"

2. Consumer Unit Upgrade (£300–£600)

Your consumer unit — the fuseboard — needs to meet current regulations (BS 7671 18th Edition) before solar can be connected. If your board predates 2008, it almost certainly needs replacing.

This isn't optional. It's a safety requirement, and a responsible installer will flag it during the site survey. The problem is that some installers don't mention it until installation day, leaving you with an unexpected bill.

What to ask: "Have you assessed whether my consumer unit needs upgrading, and is that cost included?"

3. DNO Application Wait (£0, but 4–8 Weeks Delay)

This one isn't a cost — it's a delay that nobody mentions upfront.

Systems up to 3.68kW per phase need only a G98 notification, which is instant. But most modern systems are larger than 3.68kW, meaning they need G99 approval from your Distribution Network Operator. This is free but takes 4–8 weeks for approval.

If you're expecting panels on your roof in two weeks after signing, a G99 requirement changes that timeline significantly. Your installer should tell you which application applies during the quoting stage.

4. Bird Proofing (£200–£400)

Pigeons love solar panels. The gap between the panel and your roof tiles creates a warm, sheltered nesting spot that birds will find within months. Once they're in, they cause noise, mess, and can damage wiring.

Bird proofing — mesh clips fitted around the perimeter of the panels — is simple and relatively cheap when done at the same time as installation, because the scaffolding is already there. Retrofitting it later means paying for scaffolding again, roughly doubling the cost.

Many installers don't include bird proofing as standard. Some don't even mention it.

What to ask: "Is bird proofing included? If not, what's the cost to add it now versus later?"

For more on this specific issue, see our guide on bird proofing solar panels.

5. Roof Repairs (Varies)

Your installer isn't a roofer, and most solar companies won't fix broken tiles, cracked flashing, or structural issues. If problems are discovered during installation — cracked tiles that weren't visible from the ground, weak battens, or water damage — work stops until the roof is sorted.

A pre-installation structural survey (£150–£300) can prevent expensive surprises. This is especially worth considering if your roof is over 20 years old or you've noticed any damp in the loft space.

What to ask: "Do you inspect the roof condition during the site survey, and what happens if you find issues on installation day?"

LONGi Hi-MO X6 450W

£85

watt peak

450

efficiency pct

23

dimensions mm

1722 x 1134 x 30

weight kg

21.3

View on Amazon

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6. Trenching (£200–£500)

If the cable route between your panels and your consumer unit isn't straightforward — for example, if your consumer unit is in a detached garage or outbuilding — the installer may need to trench a cable underground.

Trenching involves digging a channel (typically 600mm deep), laying ducting, running the cable, and backfilling. It's not complex work, but it adds £200–£500 depending on distance and surface type (grass is cheap; concrete or paving is expensive).

What to ask: "Where will the cable route run, and is trenching required?"

7. Export Meter

To get paid for the electricity you export to the grid via the Smart Export Guarantee, your energy supplier needs to know how much you're exporting. Most modern smart meters handle this automatically.

If yours doesn't — or if you don't have a smart meter — your supplier should replace it free of charge under the smart meter rollout. This isn't a cost to you, but it's worth confirming before your system goes live so there's no delay in starting SEG payments.

What to ask: "Will my current meter handle export readings, or do I need to request a smart meter upgrade?"

8. Monitoring Equipment (£0–£80)

Most modern inverters include WiFi-based monitoring — an app that shows your generation in real time, daily and monthly totals, and system health. But not all do.

Some inverters need a separate WiFi dongle or monitoring stick (£30–£80) to connect to your home network. Others have monitoring built in but require the installer to set it up during commissioning.

Your quote should confirm that monitoring is included and configured as part of the installation handover.

What to ask: "Does the inverter include WiFi monitoring, and will you set it up before you leave?"

The Total Hidden Cost

In the worst case — consumer unit upgrade, bird proofing, roof repairs, and trenching — you could be looking at £1,000–£2,500 on top of the quoted price.

In the best case? A thorough installer includes everything in the quote, the site survey catches any issues beforehand, and there are no surprises on installation day.

JA Solar JAM54D41 450W N-type TOPCon

£82

watt peak

450

efficiency pct

22.8

dimensions mm

1722 x 1134 x 30

weight kg

21.5

View on Amazon

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How to Protect Yourself

1. Get at least 3 quotes and compare them line by line using the same criteria
2. Ask about every item on this list during the site survey — don't assume anything is included
3. Get a roof survey first if your roof is over 20 years old
4. Confirm the DNO application type (G98 or G99) and timeline before agreeing to an installation date
5. Add bird proofing at install time — it's always cheaper now than later

For a full breakdown of what solar panels cost in 2026, see our guide on solar panel costs in the UK. And for help comparing installer quotes, read how to read a solar quote.

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