Republican and Democratic lawmakers on Friday defended U.S. installers of rooftop solar panels and made an effort to beat back a pending decision that could make imported solar panels more expensive.

Bipartisan letters from 16 senators and 53 congressman were sent to International Trade Commission Chairman Rhonda Schmidtlein, and urged the agency to reject a petition by Chinese and German-owned companies that manufactured solar panels and cells in the U.S., but have since gone bankrupt.