In this guide
Short answer: rooftop solar is the bigger investment and the bigger saving: about $31,000 for a typical system that can cover most of your bill, best for homeowners with a good roof. Plug-in solar costs $600 to $2,000, covers roughly 5 to 15% of a typical bill, needs no installer and suits renters, condos and anyone who wants to start small.
Side by side
| Plug-in kit (800 W) | Rooftop system (12 kW) | |
|---|---|---|
| Upfront cost | $600 to $2,000 | About $31,000 before incentives |
| Cost per watt | About $1 to $2.50 | About $2.60 |
| Yearly output | About 600 to 1,200 kWh | About 14,000 to 18,000 kWh |
| Share of a 10,000 kWh/yr home | 5 to 12% | Often 100% or more |
| Typical payback | 4 to 12 years | About 10 years (EnergySage) |
| Exports credited | Usually no | Usually yes (net metering or export rate) |
| Installer and permits | No (in states with a law) | Yes: permit, inspection, interconnection |
| Renters | Yes, with permission | No |
| Take it when you move | Yes | No (adds to home value) |
Rooftop figures: EnergySage's 2026 marketplace average for a 12 kW system, about $2.60 per watt. Plug-in figures: our savings estimates by state.
Why rooftop saves so much more
Size is most of it: 12 kW is 15 times bigger than an 800 W kit. The other part is exports. Rooftop systems are interconnected with the utility, so midday surplus usually earns a credit, through net metering or a lower export rate depending on your state. Plug-in kits, in nearly every state, give their surplus away. That's why a plug-in kit should be sized to your daytime use, not your whole bill. See which kit size you need.
Why plug-in still makes sense for many people
- Renters and condo owners can't put panels on a roof they don't control.
- Low upfront cost: no loan, lease or 25-year contract.
- No roof work: nothing drilled, nothing to remove when the roof needs replacing.
- Fast: a kit can be producing the day it arrives, where rooftop projects take weeks to months.
- Portable: it moves with you.
Tax credits and incentives
The federal 25D residential clean energy credit (30%) ended for systems installed after December 31, 2025, which raised the net cost of rooftop solar in 2026. It never applied in a clear way to plug-in kits. Some states, utilities and cities offer rebates or performance payments for rooftop systems; few cover plug-in kits yet.
Which should you choose?
- You own a house with a sunny roof and plan to stay 10+ years: get rooftop quotes first.
- You rent, live in a condo or have a shaded roof but a sunny balcony: plug-in, if your state allows it.
- You're unsure or short on cash: start with a plug-in kit. It shows you how much sun your home really gets.
- No roof, no balcony: look at community solar.
Already have rooftop solar? Check your interconnection agreement, and in Vermont, note that net-metered customers can't add a plug-in device.
Frequently asked questions
Is plug-in solar cheaper than rooftop solar?
Upfront, by a lot: $600 to $2,000 for a plug-in kit versus about $31,000 for a typical 12 kW rooftop system before incentives (EnergySage, 2026). Per watt, rooftop is cheaper (about $2.60 per watt versus $1 to $2.50 for kits), and it covers far more of your bill.
Which pays back faster, plug-in or rooftop solar?
It depends on your state. EnergySage reports about 10 years for rooftop systems on average. A well-placed plug-in kit pays back in 4 to 8 years in high-price states and 8 to 12 or more in low-price states, because exported power usually isn't credited.
Can I have both plug-in and rooftop solar?
Sometimes. Vermont's law says a customer with a net-metered system can't also install a plug-in device. Other states don't address it, but your utility's interconnection agreement may. Check before adding a kit.
Is there a tax credit for plug-in solar?
Not federally anymore. The 25D residential clean energy credit ended for systems installed after 2025. Some states and utilities have their own incentives; check your state energy office.
Update log
- Guide published with EnergySage 2026 cost data.
Sources and official texts