A demand forecast for 2027 is a bet. We do not publish one with a number in it, because the number would be invented. What we can do is set out what is known, which is a lot, what is uncertain, and how an installer can plan across a range. That is more use than a headline figure, and it will not embarrass you in March.
What is known
Several scheduled facts shape 2027 for installers:
- Deeming steps down. Small-scale solar moves from 5 to 4 deeming years on 1 January 2027. A 6.6 kW zone 3 system creates 36 STCs rather than 45, about $345 less at $38.50.
- The battery factor steps down. From 6.8 to 5.7 on 1 January 2027, and 5.2 on 1 July 2027. A 14 kWh battery creates 79 STCs from January and 72 from July, versus 95 now. Tiers apply: 100% of the factor to 14 kWh, 60% from 14 to 28 kWh, 15% from 28 to 50 kWh.
- Mid-scale solar is in. Systems above 100 kW and up to 1 MW installed from 1 October 2026 create STCs with a fixed five-year deeming period. Applications open mid to late November 2026, per the CER.
- The scheme ends on 31 December 2030. The slope to 2030 is public.
- Some state incentives have closed. NSW’s PDRS home battery incentive was suspended from 1 July 2025, and several loans and top-ups have gone.
What the regulator’s projections say
The Clean Energy Regulator publishes small-scale technology certificate projections, prepared by consultants, each January, and sets the Small-scale Technology Percentage for the year. The 2026 percentage is 11.67%, built on the high-scenario projections, to allow for demand from the battery program, and consistent with about 3.4 GW of rooftop solar. The projections also estimated around 24.1 million STCs from rooftop solar in 2026, excluding battery STCs. Those are a guide to industry volume, not to your own pipeline. Find the 2027 percentage and the updated projections on the CER’s site, and treat them as the best available public evidence.
Four forces for 2027
| Force | Direction for installer demand | Why |
|---|---|---|
| Smaller STC discount on rooftop solar | Slightly down | About $345 less on a standard system, and the headline “rebate drops” can deter fence-sitters |
| December 2026 pull-forward | Down in Q1, up in Q4 2026 | Jobs brought forward to beat 1 January |
| Battery program, factor 5.7 then 5.2 | Mixed | Smaller discount, but strong customer interest, and tiers favour 14 kWh |
| Mid-scale commercial solar | Up | New segment with a fixed five-year deeming period |
Add household economics. Retail tariffs, the cost of equipment and the pace of electrification all matter, and none of them are things we can forecast.
Three scenarios
Steady. Pull-forward produces a clear Q4 2026 peak and a soft Q1 2027. Batteries and commercial work fill the gap, and annual volume is close to 2026. Installers who diversified do well.
Slow. The January step and a less generous battery factor dampen household appetite. Quote conversion falls. Pressure is on smaller installers with thin margins, and consolidation continues.
Strong. Mid-scale commercial solar turns out to be a large untapped market, batteries stay popular at 14 kWh, and retail prices make self-consumption attractive. Crews are booked out.
We have no basis to pick one. Plan for the middle, and know what you would do in the other two.
Planning moves that work in every scenario
- Price to the install date. Put the date clause in every contract, so the January and July steps do not erode your margin.
- Build a battery capability. Accreditation, supplier terms, photo discipline and evidence. See battery installer accreditation.
- Look at commercial. If you have installed 30 to 99 kW systems, the 100 kW to 1 MW range is a natural next step. Read mid-scale solar and STCs.
- Control cash. Settle certificates quickly and keep a buffer for the seasonal swing. Faster settlement is worth more when volume is lumpy.
- Keep costs variable. Use subcontract capacity and flexible rosters rather than permanent headcount sized for a December peak.
From the desk: Sketch three numbers for each month of 2027: jobs you expect, jobs you could handle, and jobs you would need to break even. If the first is always above the third, you are comfortable. If it dips below in February, that is the month to line up commercial quotes or maintenance work now.
What 2027 will mean for the certificate market
For traders and installers alike, the volume of STCs is a function of installs and deeming. Rooftop volume per job falls. Battery STCs create 79 per 14 kWh job rather than 95, but jobs may rise. Mid-scale solar creates bulky claims: a 200 kW zone 3 system creates 1,382 STCs. At the time of writing the STC spot has been roughly $38 to $40 against a $40 ceiling, and the percentage sets demand. We do not expect the picture to change quickly, but we would not be surprised by lumpy claim volumes, especially around the turn of the year. See the future of the STC market.
Signals worth watching
- The CER’s 2027 percentage and quarterly reports
- Network connection queues and approvals, since delays push jobs across date lines
- Supply of CEC-approved batteries and inverters
- Retail tariff changes and any state program announcements
- Evidence and audit notices from the CER
Reading customer demand signals early
The best leading indicators are in your own business: enquiry volume, the share of enquiries that ask about batteries, quote conversion rate, average system size and the time from quote to signature. Track them monthly. If enquiries hold but conversion falls after a rebate headline, the issue is explanation, not demand. If enquiries fall everywhere, the cause is wider. Compare against what you know about the schedule: December should be strong, and January should be soft. Anything outside that pattern is news.
See also the question of rebates after 2030 and installing now or waiting, two of the questions your customers will be asking.
What to do next
- Map your 2027 jobs by month under the three scenarios
- Re-quote with the 2027 deeming and factor figures in the STC calculator and battery STC calculator
- Read pull-forward demand in December 2026 and new solar rules for 2027
- See pricing, how it works and the Partner Program
- Use the scheme changes hub for dates