Complex sentence: Modern ghost hunters employ heat sensors, such as digital thermal scanners which measure instant temperature changes--despite a lack of scientific evidence or theory to support equating the temperature with ghosts and the fact that temperatures can vary throughout a building due to normal causes.
Split into simpler sentences: Modern ghost hunters employ heat sensors, such as digital thermal scanners which measure instant temperature changes. The practice persists despite a lack of scientific evidence or theory to support equating the temperature with ghosts and the fact that temperatures can vary throughout a building due to normal causes.