Quick answer
Roof-mount solar is cheaper and works for most Illinois homes. Ground mounts usually cost more per watt because of foundations and trenching, but they can face due south at the ideal tilt, avoid roof penetrations and fit larger systems, which suits rural and large-lot homes. Check local zoning first: some towns, such as Mount Prospect, allow ground-mounted systems only in commercial areas.
How do ground-mount and roof-mount solar compare?
| Roof mount | Ground mount | |
|---|---|---|
| Cost | Lower | Usually higher per watt (foundations, trenching, longer wire runs) |
| Output | Depends on roof direction and pitch | Can face due south at the best tilt |
| Roof work | Penetrations and roof condition matter | None, so roof age doesn't matter |
| Space | Uses the roof you have | Needs open, unshaded yard space |
| Snow and maintenance | Harder to reach | Easy to reach from the ground |
| Zoning | Usually allowed with a permit | Often limited by yard, setback and height rules |
When does a ground-mount system make sense?
- Your roof faces the wrong way, is heavily shaded, or is too small for the system you need
- Your roof needs replacing soon and you'd rather not tie solar to it; see replacing your roof before solar
- You have an open, sunny yard, common on rural and large suburban lots
- You want a larger system for an EV, heat pump or farm buildings; see solar with an EV or heat pump
What zoning rules apply to ground-mounted solar in Illinois?
There's no single statewide rule; each city, village or county sets its own. Examples from towns we've researched:
- Mount Prospect allows ground-mounted systems only in commercial and industrial areas, not on home lots.
- Arlington Heights allows ground-mounted systems on residential lots in the rear yard.
- Normal adopted a Solar Energy Code in 2022 with separate rules for roof- and ground-mounted systems.
- Belleville sets height and size limits for ground-mounted home systems in its zoning code.
Unincorporated areas follow county zoning. Check setbacks, height limits and any HOA rules before you choose a design. Find your town's details on its city page.
Do ground-mounted systems qualify for the same incentives?
Yes. Ground-mounted home systems can receive the $300/kW ComEd or Ameren rebate and Illinois Shines payments like rooftop systems, as long as they meet the program rules and interconnection requirements.
Sources
This guide is general information, not tax, legal or financial advice. Incentive programs change, so confirm current terms with your installer, your utility and a tax professional.