diff --git a/flake.nix b/flake.nix
index f342daf..ebc2072 100644
--- a/flake.nix
+++ b/flake.nix
@@ -94,6 +94,7 @@
           ++ (with python3Packages; [
             numpy
             matplotlib
+            pythermostat
           ]);
         shellHook = ''
           export PYTHONPATH=`git rev-parse --show-toplevel`/pythermostat:$PYTHONPATH