What installation cost usually includes
A proper installed quote should cover the roof mounting system, panel fitting, inverter installation, DC and AC cabling, isolators, testing, commissioning and handover documents. For an MCS installation, paperwork and certification also matter because they can affect export tariff access.
Scaffolding may be included, but do not assume it is. If a quote looks surprisingly low, check whether access is provisional, excluded or priced for a very simple roof.
Labour and access are the big swing factors
A simple two-storey roof with clean access is very different from a roof split by dormers, valleys, extensions and fragile tiles. The installer is pricing risk as well as hours.
Access over a conservatory, a narrow alley or a rear extension can raise scaffolding cost. On paper, two homes may both need a 4kW system. On site, one may be a tidy job and the other may be a puzzle with invoices attached.
| Quote item | Why it matters | Question to ask |
|---|---|---|
| Scaffolding | Can materially change total cost | Is access fully included or provisional? |
| Inverter | Affects monitoring and battery options | Is it string, hybrid or microinverter based? |
| Roof mounting | Needs to suit tile type and wind loading | What mounting system is specified? |
| Electrical work | Older homes may need extra work | Is consumer unit work included? |
| MCS paperwork | Often needed for export tariffs | Will I receive MCS certification? |
Why MCS certification matters
MCS is not a magic badge, but it is a useful minimum filter for domestic solar. Many export tariff routes expect an MCS certificate or equivalent evidence, and lenders or future buyers may ask for clean paperwork.
Ask who completes the certification, what handover pack you receive and how the installer handles DNO notification. A good installer will not treat those questions as awkward.
Installation cost and system design should be read together
A design with more roof faces, optimisers or microinverters may cost more because it is solving a shading or layout problem. That can be reasonable. What you want to avoid is paying for complexity without a clear reason.
If two quotes differ by more than a small amount, ask each installer to explain the design choices in plain English. The stronger quote is often the one that survives that conversation.
Common questions
Is solar installation cheaper on a bungalow?
It can be cheaper because access may be easier, but roof shape, pitch, tile condition and cable routes still matter. A bungalow is not automatically a low-cost job.
Should scaffolding be included in the quote?
For most domestic roof installations, yes. If it is provisional or excluded, get the expected cost in writing before comparing the quote.