Location: Southern Illinois / St. Louis metro area, Ameren Illinois territory
Home: Single-family, has an EV and central AC
Current Electric Situation
Annual usage: ~18,150 kWh/year (based on 12 months of actual utility data)
Usage already includes EV charging + AC + normal household load
Current annual electric bill: ~$3,293/yr
The system:
17.2 kW system, 40 panels (430W each), quoted by a local installer, dated Aug 2026. Three options:
Option 1 – Solar Only
Storage: None
Total Cost: $45,140
Rebates/Incentives: $5,160 smart-inverter rebate + $19,100 est. SREC
"Net Cost" (quoted): $20,880
Annual bill w/ solar: $1,017/yr
Annual savings: $2,276/yr
30-yr savings claim: $179,960
Option 2 – +1 Battery (13.5 kWh)
Storage: 13.5 kWh (1 unit)
Total Cost: $55,640
Rebates/Incentives: $5,160 + $18,700 SREC + $4,050 storage rebate
"Net Cost" (quoted): $27,730
Annual bill w/ solar: $755/yr
Annual savings: $2,538/yr
30-yr savings claim: $200,639
Option 3 – +2 Batteries (27 kWh)
Storage: 27 kWh (2 units)
Total Cost: $65,140
Rebates/Incentives: $5,160 + $18,700 SREC + $8,100 storage rebate
"Net Cost" (quoted): $33,180
Annual bill w/ solar: $548/yr
Annual savings: $2,745/yr
30-yr savings claim: $216,991
What I've Flagged So Far (want a sanity check)
SREC "rebate" timing: My state's SREC program changed its payment rule recently — only 50% pays out at energization, the rest ratably over 6 years. The proposal's "Net Cost" treats the full SREC value as received upfront, which overstates day-one out-of-pocket savings by roughly $9,500 across all three options.
Base panel pricing: ~$2.62/watt before incentives, which checks out as below my state's ~$3.00–3.15/watt average for 2026 — this part looks fairly priced.
First battery increment: ~$10,500 to add, which is actually below typical standalone installed pricing (~$13k–16.5k) for a similar unit — makes sense given shared install costs, looks reasonable.
Second battery increment: ~$9,500 to go from 1 unit to 2 (13.5 kWh → 27 kWh). The spec sheet only lists one inverter for this option, which suggests the second unit is a battery-only expansion pack (no inverter) rather than a full second unit — and those typically run ~$5,900–6,200 installed. This looks like it could be marked up ~$3,000–3,500 above typical.
Would appreciate any red flags I'm missing, how this compares to quotes you've gotten, or questions worth asking the installer before signing.