How to Quote Solar Installation Jobs

Why solar quoting demands precision

Solar installation sits at the intersection of electrical work, engineering, and government rebate schemes. A roofing quote has materials and labour. A solar quote has panels, inverters, mounting hardware, electrical balance of system, STC rebate calculations, grid connection applications, and compliance documentation. Miss one component and you either absorb the cost or renegotiate mid-job.

The Australian residential solar market is competitive. Homeowners collect two to four quotes and compare them side by side. A quote that shows clear component specifications, an accurate STC rebate, and a transparent pricing breakdown wins over a lump-sum number every time. Conversely, a quote built on last quarter's panel prices or an incorrect STC calculation costs you margin before the first panel goes on the roof.

This guide covers each part of the solar installation quote with 2026 Australian benchmarks so you can price accurately, size systems correctly, and present a proposal that converts.

Step 1: Calculate your true cost per installation

Before pricing a system, work out what a day of installation actually costs your business. Solar installers typically price by the job rather than the hour, but you need to know your daily cost to set margins that sustain the business.

For a sole-operator solar installer, total annual costs typically land between $114,000 and $192,000. At around 220 billable days per year, your loaded cost per day sits between $520 and $870. Most solar businesses run a crew of two on residential installs, so your daily site cost is roughly double that: $1,040 to $1,740 before margin.

Labour accounts for approximately 25-30% of a residential solar installation. The rest is components and compliance. Your margin comes from efficient installation (more jobs per week), smart component procurement (volume pricing from distributors), and accurate quoting (no margin erosion from pricing errors).

If you employ staff, add workers compensation premiums (electrical trades carry moderate WHS risk ratings), redundancy contributions, and any allowances under the Electrical, Electronic and Communications Contracting Award.

Step 2: Size the system to the customer

System sizing is the first step in any solar quote. An undersized system leaves the customer disappointed. An oversized system wastes their money. Getting the size right builds trust and reduces post-install complaints.

Residential sizing guide

The 6.6kW system is the most common residential size in Australia. It pairs with a 5kW inverter (the single-phase export limit in most DNSP areas) and produces roughly 24-28kWh per day in capital cities, covering most household consumption.

Factors that affect sizing

• Available roof space: a standard 440W panel is approximately 1.9m x 1.1m (2.1m2). A 6.6kW system needs 15 panels and roughly 32m2 of suitable north-facing roof. East-west split arrays work but produce 10-15% less per panel than true north.
• Shading: nearby trees, chimneys, or neighbouring buildings that cast shadows on the array reduce output significantly. Microinverters or optimisers mitigate partial shading better than string inverters.
• Single-phase vs three-phase: single-phase homes are typically limited to 5kW inverter export. Three-phase homes can run larger inverters (8-15kW) without export restrictions. Check the customer's supply before designing the system.
• Future plans: if the customer is considering a battery, EV charger, or pool pump in the next few years, size the system larger now. Adding panels later is more expensive per watt than doing it in one install.

Always confirm the customer's most recent electricity bill. Daily usage in kWh is printed on every bill, usually as an average over the billing period. Design from real consumption data rather than assumptions.

Step 3: Choose and price the components

A solar system has four main cost categories: panels, inverter, mounting hardware, and electrical balance of system. Each should appear as a line item in your quote.

Solar panels

All panels used in Australian installations must be listed on the CEC Approved Products list. Tier-1 panels from Bloomberg NEF's bankability list carry the lowest warranty risk. Standard product warranties are 12-15 years; performance warranties are 25-30 years. Higher-efficiency panels (22%+) justify a premium where roof space is limited.

Inverters

A 6.6kW system with 15 panels and Enphase microinverters totals $2,250-$3,750 for inverter hardware alone, compared to $1,000-$2,800 for a single string inverter. Microinverters carry a 25-year warranty and handle shading better, which justifies the cost premium on partially shaded roofs. Hybrid inverters cost more up front but save the customer a second inverter when they add a battery later.

All inverters must be CEC-approved and comply with AS/NZS 4777.2 for grid connection. Match the inverter capacity to your local DNSP's export limits.

Mounting and racking

Mounting hardware is a small percentage of the total system cost but affects installation time significantly. Metal roofs are fastest: brackets clamp to the roof seams without penetrating the sheeting. Tile roofs require lifting tiles, installing hook brackets on the battens, and replacing tiles around the mount, adding 30 to 60 minutes of labour. Flat roofs require tilt frames at the correct angle for your latitude and wind-rated ballast or penetration fixing.

Electrical balance of system

Electrical BOS totals $500-$1,100 for a standard residential install. Switchboard upgrades push toward the higher end: older homes with full switchboards or outdated boards may need a sub-board or a full switchboard replacement ($800-$2,500 additional). Always inspect the switchboard during the site visit and include any upgrade in the quote rather than discovering it on install day.

Step 4: Calculate the STC rebate

Small-scale Technology Certificates are the federal solar rebate under the Small-scale Renewable Energy Scheme (SRES). The customer earns STCs based on the system size, location, and the remaining years of the scheme. In practice, the customer assigns their STC entitlement to you at the point of sale, and you pass the value on as a discount on the installation price.

STC calculation formula

Number of STCs = Zone Rating x Deeming Period x System Size (kW)

In 2026, the deeming period is 5 years (the scheme ends in 2030). The zone rating depends on the installation postcode and reflects the average solar irradiance at that location.

Worked examples (2026, STC spot price ~$40)

The STC spot price fluctuates on the open market. The STC Clearing House guarantees $40 per certificate but has a queue. Many installers sell through STC aggregators who pay slightly below spot for immediate settlement. Factor your actual expected STC revenue into the discount you offer the customer.

The STC rebate reduces each year as the deeming period shrinks (4 years in 2027, 3 in 2028, and so on). This is worth mentioning to customers who are hesitating: the rebate today is the largest it will be.

Show the STC rebate as a visible line-item discount on your quote. Customers appreciate seeing the full system price and the rebate separately rather than a net number with no explanation of how the discount was calculated.

Step 5: Factor in roof type and site complexity

The roof determines your installation time, mounting hardware, and risk profile. Always inspect the site before quoting. Satellite imagery and Google Maps give you a head start on roof layout, but they miss shading, roof condition, and access constraints that affect the price.

Installation cost modifiers by roof type

For a standard single-storey metal roof with the switchboard on the same side of the house as the array, the installation is straightforward. Each complication adds time and materials, and each should be reflected in the quote. Customers accept cost additions when you explain the reason clearly: "Your tile roof requires each panel mount to be individually anchored to the roof battens, which adds about an hour of labour and $500 in mounting hardware compared to a tin roof."

Access and safety

Working-at-height regulations apply to every solar installation. Single-storey homes are typically manageable with ladder access and a harness system. Two-storey installations may require scaffolding or a roof-edge protection system ($500-$2,000 depending on the house). If scaffolding is needed, quote it as a separate line item.

Check access to the roof for panel and equipment delivery. Tight side gates, no rear access, or second-floor arrays may require panels to be passed up by hand rather than carried directly from the truck, adding installation time.

Step 6: Compliance, licensing, and warranties

Solar installation in Australia is regulated at federal, state, and industry levels. Compliance costs are real and belong in your pricing model, not absorbed as overhead that erodes margin.

Accreditation and licensing

Grid connection

Every solar installation requires a grid connection application to the local Distribution Network Service Provider (DNSP). The application must be submitted before installation in some networks and within a set period after installation in others. Common DNSPs: Ausgrid (Sydney), Endeavour Energy (Western Sydney), Essential Energy (regional NSW), Energex (SE QLD), SA Power Networks (SA), Western Power (WA metro), AusNet / Powercor / Jemena / CitiPower (VIC).

Grid connection applications cost $0-$250 depending on the DNSP. Some are free for standard residential systems under 5kW export; larger systems or those requiring export limiting may incur fees. The application process and meter changeover timeline (one to four weeks post-install) should be communicated to the customer in the quote.

Warranty structure

Solar systems carry three layers of warranty that you should specify in every quote:

• Panel product warranty: 12-15 years for manufacturing defects (premium panels offer 25 years).
• Panel performance warranty: 25-30 years, guaranteeing the panel produces at least 80-87% of rated output at end of term.
• Inverter warranty: 5-12 years standard (Fronius and Enphase offer 10+ years; Enphase microinverters carry 25 years). Extended warranties available from most brands.
• Workmanship warranty: your own warranty covering the installation quality. Industry standard is 5-10 years. This is your liability, so factor the cost of potential callbacks into your pricing.

Step 7: Build a clear line-item quote

An itemised quote converts better than a lump sum. It shows the customer what each component costs, makes add-ons like batteries easy to price, and reduces disputes. Solar quotes benefit from itemisation because customers actively compare component brands and specifications across multiple quotes.

Worked example: 6.6kW solar installation on a single-storey tin roof in Sydney

Standard Colorbond roof, north-facing array, no shading, switchboard in good condition, single-phase supply. Mid-range tier-1 panels with a Sungrow string inverter.

Each line carries its own cost, so the customer sees where the money goes. If they want to upgrade to a Fronius inverter, you adjust one line item. If they add a battery, it appears as new lines. If the site inspection reveals a tile roof or a switchboard upgrade, those are visible additions rather than a renegotiation of the whole price.

The STC rebate is shown as a discount, not buried in the net price. Customers who see the full system cost and the rebate separately understand the value they are receiving from the scheme and can verify the calculation themselves.

Note: GST applies only if your business is GST-registered (required once turnover exceeds $75,000). If you are below the threshold, your quotes show totals without GST.

How this quote benchmarks

At $5,962 inc GST after rebates, this system sits in the middle of the 2026 national range of $5,000-$8,500 for a 6.6kW installation. That translates to $0.90 per watt after rebates. Budget systems with entry-level panels and inverters come in at $4,500-$5,500. Premium systems with Fronius or Enphase and high-efficiency panels reach $7,500-$8,500. If a competing quote is substantially below $4,500, that is a red flag for the customer: it likely uses uncertified products, undersized cabling, or a business that will not be around to honour the warranty.

Step 8: Quote battery storage as an add-on

Battery storage is a growing part of the residential solar market. Always quote it as a separate, optional section rather than bundling it into the system price. This lets the customer decide on solar and battery independently, and keeps your core solar quote competitive against installers who quote solar only.

The federal Cheaper Home Batteries Program provides approximately $3,500 off eligible battery installations in 2026. State rebates may stack on top: Victoria offers up to $2,950 for eligible homes, and the ACT offers interest-free loans. Check eligibility for each customer and show all applicable rebates on the quote.

If the customer wants a battery later, a hybrid inverter installed now saves them the cost of a second inverter. A Sungrow SH5.0RS hybrid adds roughly $350-$700 over the standard SG5.0RS string inverter. Present this as an option: "Battery-ready now for $X extra, or standard inverter with full battery retrofit later at higher cost."

Step 9: Present the quote so it converts

Homeowners buying solar are making a long-term investment. The way you present the quote affects their confidence in you as much as the price itself.

What to include

• System specifications: panel brand, model, wattage, and quantity. Inverter brand, model, and capacity. Total system size in kW. This lets the customer verify your components against the CEC approved list and compare across quotes.
• Estimated annual output: in kWh per year for your location. A 6.6kW system in Sydney produces approximately 9,000-10,000kWh per year. Show this alongside the customer's current usage to demonstrate the system covers their needs.
• STC rebate breakdown: show the calculation (zone rating, deeming period, system size, STCs, dollar value). Transparency here builds trust and differentiates you from installers who show only a net price.
• Itemised pricing: panels, inverter, mounting, electrical, labour, design, grid connection, and STC rebate as separate lines. This is your strongest trust signal.
• Warranty summary: panel product warranty, panel performance warranty, inverter warranty, and your workmanship warranty. Spell out the years and what each covers.
• Timeline: site inspection to installation to grid connection to meter changeover. Set realistic expectations for the DNSP approval and metering timeline.
• Inclusions and exclusions. Include what is covered (all equipment, installation, grid application, compliance certificates). Exclude what is not (tree trimming, switchboard upgrade if not assessed, roof repairs, asbestos removal). Clear exclusions prevent scope disputes.
• Validity period of 14-30 days. Panel prices, inverter availability, and STC spot values all move.
• Payment terms. A deposit (typically 10-20%) to secure the installation slot, and the balance on completion before the system is commissioned. Some installers offer finance through partners like Brighte or Plenti.
• Your accreditation number and insurance. SAA accreditation number, electrical licence number, and public liability insurance certificate. These are trust signals that separate accredited installers from the operators who cannot process STCs.

Timing and follow-up

Send the quote within 24-48 hours of the site inspection. Solar customers are actively shopping and often have another installer visiting the same week. Speed matters.

Follow up within three days if you have not heard back. Most homeowners collect two to four solar quotes and take one to two weeks to decide. A brief follow-up call or text keeps you in the conversation. Ask if they have questions about the components or the STC calculation rather than simply asking if they have decided.

Quoting mistakes that cost solar installers money

• Getting the STC calculation wrong. Using last year's deeming period (6 instead of 5 in 2026) inflates the rebate and costs you money when you sell the actual STCs. Always use the current year's deeming period and verify the zone rating for the specific postcode.
• Forgetting the switchboard. Older homes may need a switchboard upgrade to accommodate the solar breaker, RCD, and isolator. If you discover this on install day, you either absorb the cost or delay the job. Always inspect the switchboard during the site visit.
• Quoting from satellite only. Google Maps shows roof orientation and approximate area, but it misses shading from new trees, roof condition (sagging battens, rusted sheeting), access constraints, and the state of the switchboard. A site visit before quoting prevents costly surprises on install day.
• Using stale component pricing. Panel and inverter prices move with supply chains and exchange rates. A quote built on last quarter's distributor price list can cost you 5-10% of margin. Use current pricing from your distributor and set a 14-30 day validity on every quote.
• Undersizing the system. A customer who installs 5kW and wishes they had gone 6.6kW is an unhappy customer. Adding panels later is more expensive per watt and may require a new DNSP application. Size conservatively upward based on their actual consumption and future plans.
• Ignoring shading. A 6.6kW system with two panels shaded by a chimney for three hours each afternoon produces significantly less than rated output. String inverters are particularly affected because shade on one panel reduces the output of the entire string. If shading is present, specify microinverters or optimisers and price them into the quote.
• Burying the STC rebate. Showing only the net price after rebates looks cheaper but makes your quote harder to compare. Customers who see the full pre-rebate price at one installer and a lower net price at another cannot tell which system is actually cheaper. Show both, and explain how the rebate works.
• No workmanship warranty. Customers compare warranties across quotes. An installer who specifies a 10-year workmanship warranty wins over one who says nothing about it, even if their price is slightly higher. State your warranty term clearly.

For more on common quoting errors across all trades, see 7 Quoting Mistakes That Cost Tradesmen Money.

How to quote faster without cutting corners

The biggest bottleneck in solar quoting is the gap between the site inspection and the customer receiving a proposal. You drive to the site, inspect the roof, check the switchboard, assess shading, and by the time you sit down at the laptop you have three quotes to build, STC calculations to run, and component specs to look up. By then the customer has another installer booked for tomorrow.

FlowSpec cuts that loop. You speak your line items into your phone while you are still on site: "15 Trina Vertex S 440 watt panels, one Sungrow SG5 inverter, tin roof rail mount kit, standard electrical, two installers one day, for Sarah Chen at 42 Banksia Street Paddington." Your Xero price list fills in the numbers, and the quote lands in Xero as a draft ready to send. A job that used to take 30 minutes at the desk takes 30 seconds on site.

See how it works at FlowSpec, or check pricing ($50/month for your first quoting seat).