Most solar businesses don’t fall out with their subbies over the rate. They fall out over the money arriving late, a variation nobody agreed to, or a job that got paid twice while another one never got paid at all.
When I search for how to pay installers per job, nearly everything that comes up is a software vendor’s page. You’ll find a US-focused roundup of invoicing tools (SubcontractorHub, 2026), a solar CRM’s invoicing feature page (Solar Hub CRM, n.d.) and an explainer on accounts payable automation (Vergo, n.d.). They’re all about which tool to buy. None of them tells you how to set up the pay itself.
This article covers that part. I’ll go through the rate card, what triggers a payment, the invoice model, the pay run, compliance, and paying for quality. Software comes last, because it can only automate a process you’ve already defined.
Why per-job pay goes wrong
I’ve watched the same failure play out across a lot of install businesses. The owner agrees a rate with a new subbie over the phone. Nobody writes down what it includes, and it all works fine until the first two-storey tile roof with a switchboard nobody quoted for.
After that the arguments start. Does the subbie get paid on the day of install or once the paperwork is in? Who covers the second trip when the metre wasn’t ready? Does disposal of the old inverter cost extra? Every one of these turns into a phone call, and those phone calls add up to a relationship problem.
Paying per job works well when three things are written down before the first job goes out:
- What each job type pays and what that price includes.
- What evidence has to exist before a job counts as payable.
- When and how the money moves.
Step 1: Build a per-job rate card
A rate card is one page listing your job types, the pay basis for each, what’s included, and what counts as a variation. It should go out with the subcontractor agreement and get reviewed whenever system sizes or product mix shift.
I haven’t put dollar figures in the table below on purpose. Rates depend on your state, your market, roof types and how much of the work your subbies do, so a number from me would just be a guess. Fill in your own figures.
| Job type | Pay basis | Included in the rate | Variation applies when |
|---|---|---|---|
| Standard rooftop PV system | Per job, or per panel / per kW with a minimum | Travel within your defined zone, standard mounting, cabling, consumables, rubbish removal, commissioning | Second storey or steep pitch, tile or slate, split arrays, travel beyond zone |
| Battery add-on (at time of PV install) | Flat add-on per job | Mounting, cabling, commissioning, customer walkthrough | Bollards or protection needed, wall or location change on the day |
| Battery retrofit (standalone visit) | Per job | Travel, install, commissioning | Existing system faults found, extra protection required |
| Switchboard upgrade | Per job by board size, or quoted separately | Standard board replacement and labelling | Asbestos backing, metre relocation, mains upgrade |
| Inverter swap | Per job | Removal, disposal, install, commissioning | Isolator or cabling replacement needed |
| Callback (installer fault) | Unpaid | Rectification of their own workmanship | Not applicable |
| Callback (not installer fault) | Hourly or flat call-out | Diagnosis and minor fix | Parts or extended work, agreed in advance |
Some notes from experience:
- Per-panel or per-kW rates need a floor. Panel wattage has gone up a long way over the years I’ve been in the trade. A rate per panel that worked a few years ago can underpay on small systems and overpay on big ones. A minimum job rate deals with the first problem. Reviewing the rate whenever your standard panel changes deals with the second. Piece-rate structures for solar crews have their own setup and compliance questions, and there are guides that go through them in more detail (Piecework Pro, n.d.).
- Define your travel zone on a map, not in words. “Metro” means something different to everyone.
- Variations have to be approved before the work starts. The rule I’d use: if the subbie rings or messages the office from site and gets a yes, the variation gets paid. If they just do the work and add it to the invoice, it doesn’t. Write that rule down.
- Unpaid callbacks for installer fault are standard in most agreements I’ve seen, but the subcontractor agreement should spell out what “fault” means.
If you aren’t yet tracking what each job actually costs you compared with what you quoted, sort that out first. A rate card only protects your margin if you can see where the margin goes. I’ve written about that in job costing for solar installers.
Step 2: Tie payment to completion evidence, not just completion
“Install complete” doesn’t mean the job is finished from a cashflow point of view. You get paid when the customer pays and when your certificates are created and sold. Both depend on paperwork your subbie produces on the day.
Small-scale technology certificates (STCs) aren’t a rebate. They’re tradeable certificates created from an eligible system’s deemed generation, and liable entities have to buy and surrender them under the Renewable Energy Target. Creating them involves a set process and set documentation (Clean Energy Regulator, n.d.-a). The installer and designer also have their own eligibility requirements (Clean Energy Regulator, n.d.-b). If the photos, serial numbers or signed forms are missing, the certificates stall and your cash stalls too. I’ve covered that cashflow gap in STC lodgement and the cashflow gap, and the certificate mechanism in why STCs are not a rebate.
So a job becomes payable when all of these are true:
- Install and commissioning complete.
- Full photo set uploaded to the job file, matching the CER’s current evidence requirements for that system type.
- Panel and inverter (and battery) serial numbers recorded.
- Installer and designer declarations and the customer’s STC assignment paperwork completed.
- Electrical safety certificate issued, plus any inspection sign-off your state requires.
- Site left clean, with the customer walkthrough done.
Put this list in the agreement and on the rate card. Then apply it every time. If you pay one subbie before their paperwork is in, everyone will expect the same treatment.
Step 3: Choose an invoice model
There are two common ways to do this. Pick one and use it for everyone.
Subcontractor-submitted invoices. The subbie sends you a tax invoice for each job or each week. This is the default, and it puts the subbie in charge of their own billing. The downside is how messy it gets: different formats, missing job numbers, wrong amounts, invoices turning up weeks late, and the occasional duplicate.
Self-billing (recipient-created tax invoices). You create the invoice for the subbie from your approved jobs and send them a copy. Your rate card and job records drive the amount, so you lose most of the back-and-forth. The ATO has specific requirements for this arrangement, including a written self-billing agreement, and you’ll need to keep track of whether each subbie is GST-registered. Talk to your accountant before you set it up.
For a small installer business with a handful of regular subbies, I’d lean towards self-billing once your job records are reliable. If your job data is still scattered across texts and spreadsheets, start with subcontractor invoices and a strict template (job number, address, job type, approved variations, ABN, GST status). That’s easier than generating invoices from records you can’t trust.
Step 4: Run the approval-to-payment flow
The AP automation vendors describe this flow as job-cost coding, approval and payment (Vergo, n.d.). The idea holds up whatever tool you use. Here’s how it looks for a solar business.
- Code every line to a job. Each payment line carries a job number and a cost category (labour, variation, callback). If it doesn’t have a job number, it doesn’t get paid.
- Check against evidence. Someone in the office ticks off the completion checklist from Step 2.
- Approve. One named person approves. Approval checks the job against the rate card, not against the subbie’s memory.
- Batch. Run payments on a fixed day each week or fortnight. A predictable pay day stops most “where’s my money” calls before they start.
- Pay and send remittance. Each subbie gets a remittance advice listing every job paid, the amount, any variation, and any job held back with the reason.
A worked pay-run example
These are made-up round numbers to show how it works. They aren’t a market rate.
One subcontractor finished four jobs this week:
- Job A: standard rooftop system. Evidence complete. Payable at the rate card amount, say $1,000.
- Job B: standard rooftop system plus an approved tile-roof variation. Evidence complete. Payable at $1,000 plus a $150 variation.
- Job C: standard rooftop system. Photos missing for the inverter serial. Held, and the remittance says why.
- Job D: callback on their own earlier job. Unpaid under the rate card.
Payable this run: $2,150 plus GST if the subbie is registered, so $2,365. The remittance lists A and B as paid, C as held pending photos, and D as an installer-fault callback at no charge. When the photos come in, Job C goes into the next run.
Nobody has to make a phone call about any of this. Everything is on the remittance.
Pay-run checklist
- Every job coded to a job number and cost category
- Completion evidence checklist ticked for each job
- Variations matched to a recorded prior approval
- Subbie’s ABN and GST status checked against your records
- Insurance and licence/accreditation still current
- Duplicate check (same job, same subbie, previous runs)
- Held jobs listed with reasons
- Batch approved by the named approver
- Remittance sent the same day as payment
Step 5: The compliance side most guides skip
This part isn’t legal or tax advice. These are the questions you should take to your accountant and lawyer before you scale up per-job pay.
Contractor or employee? Calling someone a subbie doesn’t make them one. If one person works only for you, uses your gear, follows your schedule and can’t send someone else in their place, the relationship might look like employment. Sham contracting is a real risk for trades businesses. The ATO and Fair Work both publish guidance on working out the difference, and it’s worth reading before you sign people up.
ABN checks. Check every subbie’s ABN when you onboard them and again regularly after that. If a subbie doesn’t quote an ABN, you may have to withhold tax from their payments. I’ve written about checking ABN registration, and choosing subbies more generally is covered in how to select solar subbies.
GST. Only pay GST to subbies who are actually registered for it, and keep that status on file.
Super. This one catches a lot of owners out. If a contractor is paid mainly for their labour, you can still owe superannuation for them even though they have an ABN. Ask your accountant to look at each arrangement.
Payment times and Security of Payment. Every state has security of payment legislation, and it can give subcontractors the right to make payment claims and to take disputes to adjudication. In Queensland that’s the Building Industry Fairness Act, and the QBCC publishes guides on contractor payments and on how the security of payment laws work (Queensland Building and Construction Commission, n.d.-a; Queensland Building and Construction Commission, n.d.-b). Whether a particular solar job falls under these rules depends on the contract and the work. Assume your subbies know their rights, and set your payment terms so they never need to use them.
Step 6: Pay for quality, not just speed
If all you pay for is the finished install, subbies have every reason to go fast. If rework is free for them, you’ve given them a reason to cut corners.
Here are some ways to build quality into the pay:
- Unpaid rework. Installer-fault callbacks get fixed at no charge, as in the rate card. This is the simplest and most common approach.
- Holdbacks. You keep a small percentage of each job until a defect period ends. Be careful with this. In Queensland, retention money held under some contracts may have to go into a retention trust, and there are specific trustee obligations (Queensland Building and Construction Commission, n.d.-c; Housing Industry Association, n.d.). Get advice before you start holding back money.
- Quality bonuses. You pay a periodic bonus for a clean record: no callbacks, complete paperwork first time, good spot-check results. Encouraging good work usually goes down better than penalising bad work.
You can only pay for quality if you actually measure it. Regular inspections, which I’ve covered in spot-checking solar install quality, together with tracking defect rectification against jobs, give you the numbers. If you have the data, a conversation about quality doesn’t have to turn into an argument.
Step 7: Pick the tools last
Once the process is written down, here’s how the usual options handle it.
Xero and MYOB. Both are very good at bills, batch payments and remittance once a bill exists. Their weakness is that they don’t know if a job is finished, if the photos are uploaded, or if the STC paperwork is in. That check still happens by hand, outside the accounting software.
CRM-based invoicing (such as SolarHub CRM). Solar CRMs with invoicing features (Solar Hub CRM, n.d.) are mainly built around invoicing customers. Most don’t put subcontractor pay, completion evidence and rate cards together in one place. Check this carefully before you commit.
US-focused roundups. Vendor comparison lists (SubcontractorHub, 2026) are a reasonable place to start a shortlist. They don’t cover STC evidence, Australian GST or state security of payment rules, though.
The gap is the same in every case: the evidence that makes a job payable sits in one system and the payment sits in another. I’ve written about that pattern in the solar software three-tool problem.
That gap is why I’m building CurrentFlow. It’s designed to link completed jobs, subbie sign-off and completion evidence, so a job that reaches “complete” with its paperwork in can go straight into an approved pay run. It will keep rate cards, evidence and payment status in one place and work with Xero rather than replace it. It isn’t built yet. If that’s the problem you’re dealing with, you can join the waitlist at currentflow.com.au.
Whatever tools you use, start with the rate card, the payment triggers and a fixed pay day. Those three alone will stop most of the arguments.
References
Clean Energy Regulator. (n.d.-a). Create small-scale technology certificates. https://cer.gov.au/schemes/renewable-energy-target/small-scale-renewable-energy-scheme/small-scale-technology-certificates/create-small-scale-technology-certificates
Clean Energy Regulator. (n.d.-b). Rooftop solar installers and designers. https://cer.gov.au/schemes/renewable-energy-target/renewable-energy-target-participants-and-industry/rooftop-solar-installers-and-designers
Housing Industry Association. (n.d.). Requirements for retention trust accounts. https://hia.com.au/resources-and-advice/working-with-contractors/requirements-for-retention-trust-accounts
Piecework Pro. (n.d.). Piece rate pay for solar installation crews. https://pieceworkpro.com/blog/piece-rate-solar-installation
Queensland Building and Construction Commission. (n.d.-a). Contractor guide to payments [PDF]. https://www.qbcc.qld.gov.au/sites/default/files/documents/guide-contractor-payments.pdf
Queensland Building and Construction Commission. (n.d.-b). Industry guide to security of payment laws [PDF]. https://www.qbcc.qld.gov.au/sites/default/files/documents/guide-security-payment.pdf
Queensland Building and Construction Commission. (n.d.-c). Trust accounts. https://www.qbcc.qld.gov.au/running-your-business/trust-accounts
Solar Hub CRM. (n.d.). Solar invoicing software and automated billing. https://www.solarhubcrm.com.au/solutions/invoicing
SubcontractorHub. (2026). Best solar invoice software in 2026. https://www.subcontractorhub.com/blog/best-solar-invoice-software
Vergo. (n.d.). Best AP automation software for solar contractors. https://www.getvergo.com/learn/best-ap-automation-software-for-solar-contractors
FAQ
Should I pay solar subcontractors per job, per panel or a day rate?
It depends on your job mix. Per-job rates are easiest to administer when your systems are fairly similar. Per-panel or per-kW rates work better when system sizes vary a lot, provided you set a minimum job rate and review it when panel wattage changes. Day rates suit work that’s hard to scope, such as fault-finding. Whichever you choose, put it on a written rate card.
When should a subcontractor’s job become payable?
When the install is complete and the evidence is in: the photo set, serial numbers, STC paperwork, the electrical safety certificate and any inspection sign-off your state requires. Payment is tied to evidence because your own cash, including certificate value, depends on that paperwork.
Is self-billing better than having subbies send invoices?
Self-billing cuts down on errors and chasing once your job records are reliable. It does need a written self-billing agreement and careful GST tracking under ATO rules. If your job data is still messy, use subcontractor invoices with a strict template until it’s sorted.
Can I hold back part of a subbie’s payment for defects?
You can, but get advice first. Under Queensland’s framework, retention money held under some contracts may have to go into a retention trust. Unpaid rework for installer-fault callbacks is usually simpler and causes fewer arguments.
Do I have to pay super for subcontractors with an ABN?
Possibly. If a contractor is paid mainly for their labour, super obligations can apply even though they have an ABN. Ask your accountant to review each arrangement.