How Can We Reduce Solar Soft Costs? Part 2: Lowering Installation Labor Costs


A PV Solar Report Series

It’s no news to anyone in the solar industry that although module costs have plummeted, soft costs for solar  — like permitting, installation, and customer acquisition — have remained high in the U.S. At over 50% of system costs, our soft costs are twice those in Germany.


We know what the issues are. But how do we bring down our soft costs and enable more people to go solar?


This series, based on sessions at Solar Power International 2013, sheds light on how we can reduce time and costs associated with solar permitting, installation, and customer acquisition.


Solar installation labor costs


When it comes to reducing solar soft costs, people often think about permitting and customer acquisition. But there’s another important category to consider: installation labor costs.


At Solar Power International last week, Jesse Morris of the Rocky Mountain Institute (RMI) talked about a joint project of RMI and Georgia Tech Research Institute (GTRI) to help lower solar installation costs. The project is looking at all sectors, but at SPI, Morris focused on residential installations.


It’s important to point out that the point is not to take revenue away from installers but to lower their costs. It’s up to them whether to pass those savings along to their customers.

The project uses two tools, an installation survey and time and motion studies. The survey collects and aggregates detailed cost data related to the installation process, in order to identify best practices for each installation step.


Time and motion studies measure waste within a system. In these studies, RMI and GTRI directly observe and document the timing and physical motion of each step of the solar installation project. The goal is to provide a quantitative basis to lower installation labor costs.


Best practices for lowering installation costs


What are the differences between U.S. and German solar installation practices? There is no one answer, but German installers are doing each step of the process faster. Yet they take more breaks, drink beer during lunch, and often have less training than their U.S. counterparts.

German installers have some advantages: They’re working on clay tile roofs that don’t require as much preparation. And they may experience efficiencies because of having bigger backlogs.

Still, the studies so far have identified some best practices and opportunities for installation:


  • Prepare rails on the ground instead of on the roof.

  • Lower installation timeframes from 3 – 5 days to 1 day. This can save 10 – 15 cents a watt by eliminating travel time and setup each day.

  • Use PV-ready electrical circuits. There isn’t much available now to facilitate this, so we need products on the market to fill this hole. This item shows that we need hardware solutions in addition to efficiencies solutions.


Next steps

RMI and GTRI are continuing their studies, and you can help.


If you’re a solar residential rooftop installer, you can participate in this program by taking the installer survey. If you’re interested in participating in their time and motion studies, you can contact them directly at