What to look for
- Soft brushes and purified or deionized water
- Liability insurance and safe roof practices
- Clear pricing per panel and any minimum fee
- An inspection for cracks, loose wires and pests
- Reviews from solar owners
Questions to ask before you hire
- What cleaning method and water do you use?
- Is there a minimum job fee?
- Do you check panels and wiring while you're up there?
- Do you offer bird-proofing or critter guards?
- Will this cleaning meet my panel warranty's rules?
Getting and comparing quotes
Give each company your panel count and roof height. Compare per-panel prices and minimum fees, since small systems often hit the minimum.
Red flags
- Uses a pressure washer on panels
- Walks on the panels
- No insurance for roof work
- Can't explain their method