Every house is unique, and many are subtly altered over time as owners and contractors make a variety of changes and improvements. It could take up to 2 weeks for the engineers to fully survey the house and gather all of the specific information they need. The gathered data isn’t limited to the house itself – the engineers will also be looking at your utility connections and generally making sure that the house is ready to have a solar system installed. This is rarely a problem for newer homes, but old houses may actually have faulty wiring or other issues. There is a small chance that an electrician may need to do some work before the solar installation can proceed – if so, you may experience delays until the electrician is available. Most electricians can complete a job on a residential home in several hours (at most).