diff --git a/README.md b/README.md
index a720e0d..74d629f 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Generally, installing from source (see section `Source Installation from Git`) l
 
 ## Role Variables
 
-The variable `certbot_install_from_source` controls whether to install Certbot from Git or package management. The latter is the default, so the variable defaults to `no`.
+The variables `certbot_install_from_source` and `certbot_install_with_package` control whether to install Certbot from Git or package management. The latter is the default, and you can set both variables to `no` to use a Certbot installed outside of this role.
 
     certbot_auto_renew: true
     certbot_auto_renew_user: "{{ ansible_user | default(lookup('env', 'USER')) }}"
diff --git a/defaults/main.yml b/defaults/main.yml
index 7002b26..3ed8ef6 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -27,6 +27,10 @@ certbot_create_standalone_stop_services:
   # - apache
   # - varnish
 
+# To install Certbot with the OS package, set this variable to `true`.
+# If you are installing from source (see below) or manually, set this to `false`.
+certbot_install_with_package: false
+
 # To install from source (on older OSes or if you need a specific or newer
 # version of Certbot), set this variable to `yes` and configure other options.
 certbot_install_from_source: false
diff --git a/tasks/main.yml b/tasks/main.yml
index 52aa6af..32e38bd 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -5,7 +5,7 @@
   when: ansible_os_family == 'RedHat'
 
 - import_tasks: install-with-package.yml
-  when: not certbot_install_from_source
+  when: certbot_install_with_package
 
 - import_tasks: install-from-source.yml
   when: certbot_install_from_source