Plug-In Solar vs Full Rooftop Solar with the ITC: Which Pays Back Faster?

The 30% federal Residential Clean Energy Credit (ITC) makes a $30,000 rooftop system effectively cost $21,000. That's a meaningful subsidy — but it doesn't automatically make rooftop the right choice for every household. Plug-in kits sit in a different economic zone: no ITC access, but 30–50× lower upfront cost.

The comparison

Rooftop 10kW system with ITC

• Gross cost: ~$30,000
• After 30% ITC: $21,000
• Annual generation: 14,000 kWh
• Annual savings (at 16.5¢): $2,300
• Payback: ~9 years
• Warranty: 25 years

Plug-in 800W kit

• Gross cost: ~$800
• ITC eligible? No (system must be permanently installed and permitted)
• Annual generation: 1,000 kWh
• Annual savings (at 16.5¢): $110–$165
• Payback: ~5–7 years
• Warranty: 5–10 years

Rooftop wins on absolute savings ($/year). Plug-in wins on:

• Capital risk — $800 vs $30,000 is a much smaller commitment
• Renter friendly — rooftop needs owned property; plug-in doesn't
• Move-friendly — take plug-in with you when you sell
• No roof modifications — critical for HOAs, historic districts, tile roofs

When plug-in is the right call

• You rent (no rooftop option period)
• You plan to move within 5 years
• Your roof is unsuitable (heavy shading, wrong orientation, tile that installers avoid)
• You want to dip a toe in before committing $30k
• You can't access the ITC (low tax liability)

For state-specific numbers see the California plug-in guide.