diff --git a/install-pi.sh b/install-pi.sh
index dabeb95..da80d37 100755
--- a/install-pi.sh
+++ b/install-pi.sh
@@ -111,7 +111,7 @@ if [ -z "$PI_BIN" ]; then
 		"$HOME/.npm/bin/pi" \
 		"/usr/local/bin/pi" \
 		"$HOME/.nvm/versions/node/$(ls "$HOME/.nvm/versions/node/" 2>/dev/null | tail -1)/bin/pi" \
-		"$NVM_DIR/versions/node/$(ls "$NVM_DIR/versions/node/" 2>/dev/null | tail -1)/bin/pi"; do
+		"${NVM_DIR:-$HOME/.nvm}/versions/node/$(ls "${NVM_DIR:-$HOME/.nvm}/versions/node/" 2>/dev/null | tail -1)/bin/pi"; do
 		if [ -x "$candidate" ]; then
 			PI_BIN="$candidate"
 			break