diff --git a/install_and_test.md b/install_and_test.md
index 9df67cb6bab02dfe2fa06fe277bb33abef113af7..ad7ae3c13f20c3621cd4fcd5a0f4578243c7a2d0 100644
--- a/install_and_test.md
+++ b/install_and_test.md
@@ -64,7 +64,20 @@ To run the C and python tests of the installed `hotwheels` components, run:
 python -m hotwheels.checkup hotwheels
 ```
 
-The tests will be run using envirnoment varialbe `CC` for the C ompiler (will default to `gcc`), `MPICC` for the MPI compiler (will default to `mpicc`),   `CXX` and `MPICXX` for the c++ version (will default to `g++` and `mpicxx` respectively). 
-
-The PM run needs the `gsl` and `fftw3` to be installed. They should be either in a standard path (`/usr/{lib,include}`) or in your compiler search path (namely, in your `C_INCLUDE_PATH`, `CPLUS_INCLUDE_PATH`, and `LD_LIBRARY_PATH` env variables).
+# Environment variables
+
+Here below some relevant environment variables to change hotwheels default settings:
+
+| Environment Variable | Description                                                                                           |
+|----------------------|-------------------------------------------------------------------------------------------------------|
+| `CC`                | C compiler (defaults to `gcc`).                                                                      |
+| `MPICC`             | MPI C compiler (defaults to `mpicc`).                                                                |
+| `CXX`               | C++ compiler (defaults to `g++`).                                                                    |
+| `MPICXX`            | MPI C++ compiler (defaults to `mpicxx`).                                                             |
+| `HW_BUILD`          | Folder with runtime-generated headers, and C/C++ compiled object files.                              |
+| `HW_DATA`           | Folder where downloaded test initial conditions (ICs) should be placed.                              |
+| `DEBUG`             | Set to `1` to enable additional verbose output for debugging purposes.                               |
+| `C_INCLUDE_PATH`    | *(used by the gnu compiler)* Search path for C headers, should include paths for required libraries like `gsl` and `fftw3`.       |
+| `CPLUS_INCLUDE_PATH`|  *(used by the gnu compiler)* Search path for C++ headers, should include paths for required libraries like `gsl` and `fftw3`.     |
+| `LD_LIBRARY_PATH`   | *(used by linux)*  Search path for runtime libraries, should include paths for required libraries like `gsl` and `fftw3`.|