diff --git a/scripts/install b/scripts/install
index c4f2d02..99e3b7e 100755
--- a/scripts/install
+++ b/scripts/install
@@ -7,6 +7,7 @@
 #=================================================
 
 source _common.sh
+source ynh_exec_as
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -94,14 +95,24 @@ ynh_app_setting_set --app=$app --key=final_path --value=$final_path
 # Download, check integrity, uncompress and patch the source from app.src
 ynh_setup_source --dest_dir="$final_path"
 
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Configuring system user..." --time --weight=1
+
+# Create a system user
+ynh_system_user_create --username=$app --home_dir=$final_path
+
 #=================================================
 # Install through npm
 #=================================================
 ynh_script_progression --message="Installing node-red..." --time --weight=2
 
+chown -R $app: $final_path
+
 pushd $final_path
 ynh_use_nodejs
-npm install --production
+exec_as $app env PATH=$PATH npm install --production
 popd
 
 #=================================================
@@ -114,14 +125,6 @@ ynh_script_progression --message="Configuring nginx web server..." --time --weig
 # Create a dedicated nginx config
 ynh_add_nginx_config
 
-#=================================================
-# CREATE DEDICATED USER
-#=================================================
-ynh_script_progression --message="Configuring system user..." --time --weight=1
-
-# Create a system user
-ynh_system_user_create --username=$app --home_dir=$final_path
-
 #=================================================
 # PHP-FPM CONFIGURATION
 #=================================================
diff --git a/scripts/upgrade b/scripts/upgrade
index 383b9fd..4ee9635 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -7,6 +7,7 @@
 #=================================================
 
 source _common.sh
+source ynh_exec_as
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -115,14 +116,24 @@ then
 	ynh_setup_source --dest_dir="$final_path"
 fi
 
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Making sure dedicated system user exists..." --time --weight=1
+
+# Create a dedicated user (if not existing)
+ynh_system_user_create --username=$app --home_dir=$final_path
+
 #=================================================
 # Install through npm
 #=================================================
 ynh_script_progression --message="Installing node-red..." --time --weight=2
 
+chown -R $app: $final_path
+
 pushd $final_path
 ynh_use_nodejs
-npm install --production
+exec_as $app env PATH=$PATH npm install --production
 popd
 
 #=================================================
@@ -133,14 +144,6 @@ ynh_script_progression --message="Upgrading nginx web server configuration..." -
 # Create a dedicated nginx config
 ynh_add_nginx_config
 
-#=================================================
-# CREATE DEDICATED USER
-#=================================================
-ynh_script_progression --message="Making sure dedicated system user exists..." --time --weight=1
-
-# Create a dedicated user (if not existing)
-ynh_system_user_create --username=$app --home_dir=$final_path
-
 #=================================================
 # PHP-FPM CONFIGURATION
 #=================================================
diff --git a/scripts/ynh_exec_as b/scripts/ynh_exec_as
new file mode 100644
index 0000000..11b056b
--- /dev/null
+++ b/scripts/ynh_exec_as
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+# Execute a command as another user
+# usage: exec_as USER COMMAND [ARG ...]
+exec_as() {
+  local USER=$1
+  shift 1
+
+  if [[ $USER = $(whoami) ]]; then
+    eval "$@"
+  else
+    sudo -u "$USER" "$@"
+  fi
+}