We use the most accurate and recent aerial imagery available and are conservative in our placement of solar panels with respect to space on the roof. In addition, we require homeowners to upload photos of their roof, main panel and any subpanels so that we can assess the full scope of work. But there will be times when the site conditions don’t exactly match the information we based our design and spec on. In those cases, we allow the homeowner to choose whether they would like Sentinel to update the project spec and re-issue the request for bids or whether they would like to continue with the current quotes and contractors. If the project spec is updated and a second bid is required, Sentinel does not charge a fee for the second bid.