The TES Level 1B products are written in NCSA's HDF5 format. The Level 2 and Level 3 data products are written in HDF-EOS 5 (based on HDF5) format. TES Level 2 Lite Products are in netCDF-4 format.
Below are links to tools that will assist you in reading the data:
The HDF-EOS Tools and Information Center provides more information about the use of HDF formats.
The HDFView software can be used to browse and edit HDF5 files.
TES Read Software is provided by the NASA Langley Atmospheric Science Data Center (ASDC)
The ASDC supports a subsetting tool for TES data