A new type of transparent heat mirror for solar‐energy applications has been fabricated by chemically etching a Sn‐doped In2O3film to form a transparent conducting microgrid. For square openings 2.5 &mgr;m on a side, separated by lines 0.6 &mgr;m wide, the solar transmission increases from 0.8 for the original continuous film to 0.9 for the microgrid. Although 65% of the area of the film is removed by etching, the infrared reflectivity decreases by only 9%, from 0.91 to 0.83. A smaller decrease in the infrared reflectivity may be possible if materials with higher optical conductivity are used.