Residential
Solar EnergyNambucca Heads NSW

FREE RESOURCE

The Solar Quote Comparison Checklist

Fifty questions. Every one is something a good installer answers without flinching, and something a bad quote hopes you never ask. Print it, take it to the appointment, and write the answers next to each line.

If an installer cannot or will not answer, that is your answer.

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01

System sizing and design

  1. 01How did you arrive at this system size? Was it based on my last 12 months of usage, or on a roof limit?
  2. 02What is my annual usage in kWh, and what will the proposed system generate annually?
  3. 03What percentage of my usage do you expect the system to offset, and what self consumption rate did you assume?
  4. 04Which roof planes are being used, and what are the orientation and tilt of each?
  5. 05How was shading assessed, and can I see the report?
  6. 06Am I single phase or three phase, and does the design suit that?
  7. 07What is my export limit from the network, and does the inverter stay inside it?
  8. 08Is the inverter oversized relative to the panels, or the other way around, and why?
  9. 09What happens to my production on a cloudy day and in December versus June?
  10. 10If I add a battery or an EV later, what changes in this design?
02

Equipment, named and specified

  1. 11Exact panel brand, model and wattage. Not tier 1, the actual model.
  2. 12Panel product warranty in years, and performance warranty with the guaranteed degradation per year.
  3. 13Exact inverter brand and model, and whether it is a hybrid.
  4. 14Inverter warranty in years, and who performs the warranty work locally if it fails.
  5. 15For batteries: chemistry, total capacity, usable capacity, and round trip efficiency.
  6. 16Battery warranty in years and in cycles, and what state of health it guarantees at year ten.
  7. 17Battery backup: what actually stays on during an outage, and what is the changeover time?
  8. 18Are the mounting system, isolators, cable and switchboard gear specified, or left to the day?
  9. 19Is anything in this quote reconditioned, second hand or end of line stock?
03

Warranty, accreditation and insurance

  1. 20Who is the CEC accredited installer who will be on site, and who is the accredited designer?
  2. 21What is the electrical contractor licence number for the business doing the work?
  3. 22Public liability insurance amount, and is the certificate current?
  4. 23Who holds the contract, the company or a subcontractor?
  5. 24In NSW, what home building compensation cover applies to this work?
  6. 25If the company stops trading, which warranties survive and who honours them?
  7. 26Are the warranties transferable to a new owner if I sell the house?
  8. 27What voids the warranty: roof type, coastal corrosion, vermin, unauthorised changes?
04

Savings, tariffs and the honest numbers

  1. 28Show me the savings calculation with the self consumption rate, feed in tariff and degradation assumption used.
  2. 29What feed in tariff did you use, and what happens to savings if it drops again?
  3. 30Have you assumed 100 percent of generation is used at my retail rate? If so, why?
  4. 31What are the network and retailer charges that changed in the last two years and affect this?
  5. 32What is the payback in years at your assumptions, and at half the self consumption rate?
  6. 33What is the STC rebate amount in dollars, shown separately from the system price?
  7. 34Are there any proposed rule changes or tariff reforms I should know about before signing?
05

The battery decision, the one most people get wrong

  1. 35What share of my usage happens after the sun goes down, based on my actual data?
  2. 36What is the battery payback in years at current tariffs, not at best case tariffs?
  3. 37If the payback is longer than the warranty, say so plainly. Is this battery being sold to me for backup rather than savings?
  4. 38What is my evening peak load in kW, and can this battery cover it?
  5. 39Is this battery approved for virtual power plant participation, and what does that pay?
  6. 40If I wait twelve months, what is likely to change in price and in product?
06

Quote hygiene and contract terms

  1. 41Is the price itemised by equipment and labour, or one lump sum?
  2. 42Is the price fixed, and what can trigger a variation after signing?
  3. 43What is the deposit, and does it exceed the legal limit in NSW?
  4. 44What is the payment schedule, and how much is due before the work is finished?
  5. 45What is the installation date window, and what is the remedy if it slips?
  6. 46Who lodges the connection application with the network, and how long does approval take?
  7. 47What happens if the roof needs work, or the switchboard needs replacing, and is that in the price?
  8. 48What is the process if I find a fault in the first 12 months?
  9. 49Are there exit fees, restocking fees or cancellation charges?
  10. 50Put the answers in writing with the quote. Will you?

How to score the quotes

Give each quote a mark out of ten for how completely it answers sections one to three, the design and the paperwork.

A cheap quote that scores six is not cheap. An expensive quote that scores ten is usually the better buy, because the risk sits with them, not you.