The fastest way to compare solar quotes is to stop looking at the bottom-line price first. Put the quotes side by side and check the same eight lines on each: system size, panels, inverter, mounting, extras, STC treatment, warranties and monitoring. Then read the exclusions. Only when those lines match, or you understand exactly why they differ, does comparing the price tell you anything useful.

Set up a fair comparison before you start

Quotes arrive in different formats, so copy the key details into one simple table of your own. Leave a blank wherever a quote does not say something. A blank is itself a finding, because anything not written down is not part of the deal. Ask each installer to fill the gaps in writing rather than accepting a verbal answer.

It also helps to make sure every quote starts from the same information. If one installer inspected your roof and switchboard and another priced the job from a satellite image, the two numbers are not describing the same work. Give each company the same recent electricity bills and tell them the same plans, such as a future battery or an electric vehicle, so the designs answer the same brief.

The eight lines to check on every quote

System size and equipment: compare like with like

Start with kilowatts, not panel numbers. Sixteen lower-wattage panels can add up to less capacity than fifteen higher-wattage ones, so multiply wattage by quantity and check the total matches the headline system size. Then note the inverter rating. A 6.6 kW array on a 5 kW inverter is a common and sensible design in NSW, but if one quote uses a 5 kW string inverter and another an 8 kW hybrid, you are comparing different products with different futures.

Write down the exact panel and inverter models and look up each datasheet. Two quotes can name the same brand but different product lines, with different efficiency, temperature performance and warranty terms. If a quote says "or equivalent", ask what the substitute would be and make any change subject to your written approval. The inverter guide explains which datasheet lines matter most.

Mounting rarely gets attention until something leaks. The quote should name the racking system and confirm it suits your roof, whether tile, metal or flat. Tilt frames on a low-pitch or flat roof add cost and should be listed separately. If your home is in an exposed, high-wind location, ask whether an engineering check is included.

Extras and exclusions: where quotes quietly differ

This is the line most likely to explain a large price gap. One installer may include items another leaves out and adds later. Look for each of these and mark it included, excluded or not mentioned:

• Switchboard upgrade, if your board has old fuses or no room for new protection devices
• Meter exchange and any retailer or metering fees
• Network connection application and any export limit that applies
• Double-storey or steep-roof access, scaffolding or edge protection
• Split arrays across more than one roof face
• Asbestos in the switchboard or roof, which needs specialist handling
• Removal and disposal of an old system
• Travel charges outside the metropolitan area

A quote that includes all of these is not automatically more expensive; it may simply be more complete. Once you add the excluded items you are likely to need, the cheapest quote on paper can end up in the middle of the pack.

STCs: check the price before and after the discount

Small-scale Technology Certificates reduce the upfront price of new solar at the point of sale. For a typical 6.6 kW system installed in 2026 the discount is roughly $1,700-$1,800, and the value steps down each 1 January while the scheme runs to 2030. The installer creates and assigns the certificates, so every quote should show:

• The price before the STC discount
• The number of certificates and the value applied
• The final price you pay
• What happens to the price if installation slips past 1 January

If one quote shows the discount and another does not, you cannot compare them until both are on the same basis. The STC rebate guide explains how the certificate value is worked out, and you should confirm current values on the Clean Energy Regulator's official page before signing.

Warranties and monitoring: read the terms, not the headline

Separate the four warranties before comparing them. Panel product warranties cover manufacturing defects. Performance warranties cover output loss over time, and panels commonly lose around 0.4-0.55% of output a year. Inverter warranties are usually much shorter. The workmanship warranty covers the installation itself, and it is the one only the installer can honour, so note its length and what it covers, such as roof leaks caused by the work.

For monitoring, ask whether you will see only what the panels produce or also what your home consumes. Consumption monitoring needs an extra meter or current sensors, and it is the only way to see how much of your solar you actually use. Confirm the monitoring account will be registered in your name.

Turn the quotes into a price per kilowatt

Once scope and equipment line up, divide each final price, after STCs and including the extras you will need, by the system size in kW. Published indicative prices for Sydney in 2026 put a 6.6 kW system at around $4,500-$6,500 after STCs, which works out to roughly $680-$985 per kW. A quote well below that range with premium equipment deserves questions. One well above it should come with a clear reason, such as a complex roof or a battery-ready hybrid inverter. The Sydney solar cost guide gives ranges for larger systems. All of these prices are indicative and only confirmed after a site assessment.

Next steps

Fill in your table for each quote, send each installer a short list of the blanks, and compare only once the answers are back in writing. If you would like a design-based estimate of size, yield and payback for your own roof first, the Solar Feasibility Report in the market starts from $149 (indicative). When you are ready for a quote built on a genuine in-home inspection, request a free assessment from Blue Energy Solar.

Frequently asked questions

How many solar quotes should I get?

Three is a practical number for most homes. One quote gives you nothing to measure against, two can leave you unsure which is the outlier, and more than four tends to add confusion rather than clarity. Choose installers that inspect the site in person, so each quote reflects your actual roof, switchboard and shading rather than an estimate made from a photo.

Is it reasonable to ask an installer to match another quote?

You can ask, but first make sure the quotes are genuinely comparable. If the lower quote uses a different inverter, leaves out a switchboard upgrade or offers a shorter workmanship warranty, asking another installer to match it may simply push them to cut the same corners. It is usually more useful to ask each installer to explain the specific lines where their quote differs.

Should a solar quote include an estimate of annual generation?

Yes. A good quote estimates production for your roof's orientation, tilt and shading, not a generic figure for the system size. As a rough guide, a 6.6 kW system in Sydney produces around 24-27 kWh a day on average, and less on east or west roofs or with shade. Ask how the estimate was calculated so you can compare it fairly between quotes.