Features
Heat includes a number of Features:  
Syntax highlighting: Keywords, symbols and variables are displayed in different colours to make Haskell programs easier to read.
Error message explanations: Whenever compilation or evaluation produces an error, the information window displays further explanations and related examples, including suggestions of possible solutions. This feature can be turned on/off in the Options.  
Status: Informs about the compilation state of the code in the Editor Window
The green tick means that the code compiled successfully and evaluation of expressions in the console is enabled.
The red cross means that compilation aborted with an error.
the blue ball with a '?' means the code was modified and has not yet been compiled.
 
Help: The Help gives a brief description of how to use HEAT, including simple how to tutorials to operate HEAT.  

Error Line Focusing: When a compilation error occurs, the editor displays and highlights the line mentioned in the error message.

Code Navigation: The summary tree window provides a structured list of defined entities, aiding the locations of functions, algebraic types, type synonyms and properties in the code.

Testing: All Boolean test properties, i.e. constants whose name starts with prop_ are evaluated. In the summary tree window successful and unsuccessful test properties are marked as such. open file.

Interrupt: An evaluation, whether of a normal expression or testing of properties, can be interrupted through press of a button.