Volume pricing exists because a trader that sells certificates in bulk to liable entities prefers predictable, clean supply. The STC market is tight: spot has been roughly $38 to $40 at the time of writing, against a clearing house ceiling of $40. That leaves a narrow band for any premium.
Where the money actually is
On a 6.6 kW system, one dollar of rate difference is only a few dozen dollars per job. A fee of the same size, or a week of waiting for payment, can cost you more. So compare the full picture:
| Factor | Why it matters |
|---|---|
| Headline rate | Visible, but the band between traders is small |
| Fees | Any processing, admin or monthly fee comes straight off |
| Settlement days | Cash tied up is cost for a small crew |
| Rate lock | Is it fixed at lodgement or at payout? |
| Tiers | Do perks arrive at a set number of STCs per month? |
How to ask
Give the trader your monthly STC count and ask three things: what tier you fall in, what changes at the next tier, and whether the rate is locked on lodgement. If the answer is a vague “we will look after you”, ask for numbers in writing.
A worked comparison
Say you lodge about 400 STCs a month. A trader offering a premium of 50 cents per STC on a 400 STC tier pays you $200 extra a month. Another trader with no premium but a 24-hour settlement avoids having about a third of a month of certificate value, roughly $5,200, tied up compared with a 10 day wait. If your overdraft costs you even a modest rate, the faster settlement can be worth more than the premium. The right choice depends on your cash position, not on the rate card alone, so run your own numbers before deciding.
What this means for installers
Pick a trader whose rate is published and who shows how perks scale. Our Partner Program has three tiers and rewards volume without charging fees, and today’s rates are listed publicly. For a broader comparison method, use the certificate trader checklist and the switching guide.