About the numbers
Ask for each of these as a figure, not as a range or a reassurance.
- What is the total I will pay over the whole term, not the monthly payment?
- Is the amount being financed the same as the price of the system? If not, what is the difference and what is it for?
- Does the payment change at any point? Show me the schedule.
- What is this estimate comparing against — my current utility bill, or a projected future one?
- What happens to my payment if I do not claim or do not apply the tax credit?
About the system
- How much is this system expected to produce, and does the agreement itself commit to that figure anywhere, or only the proposal?
- What proportion of my current usage will it actually cover?
- What will my utility still charge me each month after it is running?
- What happens if it produces less than estimated?
About the paperwork
- Will you email me every document I sign, today, before I sign it?
- Which company am I contracting with, and which company is financing?
- Will anything be recorded against my property?
- What is the cancellation window, and how do I use it?
Two habits that help more than any single question
Ask for the documents before the signing appointment, not during it. A company willing to sell you a twenty-five year agreement can email you a draft to read the night before.
And take the time. Pressure to sign at a single visit — an offer that expires this evening, a price only good today — is a reason to slow down, not to hurry. Nothing about a system that will sit on your roof for two decades genuinely has to be decided in one sitting.