If solar quotes differ, check whether they describe the same job.
A lower headline price can still leave you unsure what is included. If you have written proposals, use the same questions to compare scope, assumptions and terms before choosing. This page is a self-guided check; it does not compare documents for you.
A side-by-side check you can use now
For each proposal, note its answer to these questions. If you only have one proposal, the same checks help you spot questions to ask before accepting it. Until differences in equipment, included work and warranty coverage are resolved, a headline price cannot tell you whether the proposals cover the same job; signing without clarifying them can leave scope or support expectations uncertain. Ask each installer to explain the differences in writing before you decide.
1. Make the scope comparable
What exactly is included in the installed price?
Write down panel count and kWp, exact panel and inverter models, any battery's usable kWh and power rating, roof layout, scaffolding, electrical work, monitoring and commissioning. Mark missing items as 'not stated', not zero. Ask for a revised written scope before comparing totals.
2. Separate output from savings
Are the forecasts built on the same assumptions?
Compare annual kWh estimates with roof orientation, pitch, shading and system losses stated. Then compare assumed self-use, export, electricity rates and future usage. A higher generation estimate or shorter payback may reflect different inputs; neither is a guarantee.
3. Check what could change the price
Which costs are fixed, excluded or subject to a survey?
Check VAT treatment, roof repairs, access, grid connection work, deposit, payment stages and chargeable variations. If a site survey or network response is outstanding, ask what happens if the design or price changes before you commit.
4. Know who stands behind the work
Who is the contracting party and who handles problems later?
Compare workmanship, product and performance warranties separately, including exclusions, labour and claim routes. Verify the installer's current credentials directly with the relevant scheme and ask for handover documents and aftercare terms.
If a line is missing from one proposal, ask that installer to clarify it in writing. If you have only one proposal, use the questions to identify what is still unclear. An estimate is not a final design; independently check technical and contractual claims before signing.
More ways to prepare
- Read a guide to checking solar quotes for modelling and contract questions.
- Download the printable home quote checklist to take notes.
- For a commercial roof, explore business solar considerations before comparing site proposals.
Want to talk through your solar plans?
Tell us about the property and the questions you have. If you request contact, a person can review the enquiry and follow up to discuss them with you. This form does not compare uploaded proposals or return an instant price. An installer introduction is optional and requires separate permission; we do not promise multiple quotes or an installer match.