Danfoss has introduced a roof clip that is the same as the other manufacturers: https://morelectricheating.com/products/MANUFACTURERS/DANFOSS/RX-C%20ROOF%20CLIP.aspx They have a real nice installation guide it is linked below. It says DO NOT NAIL OR SCREW TO YOUR ROOF! They say to only use adhesive and to consult roofing supplier for recommended adhesives and specifically mention asphalt shingles. https://morelectricheating.com/contentonly.aspx?file=product_pdf_info/RX-C_Roof_Clips_Data_Sheet_VDLWA122_3_16.pdf […]