We have a Kohler whole house generator that runs on NG.
It will power the whole house when needed. It runs every Monday to self check.
We have a 20KW Kohler automatic whole-house system that runs from a very large propane tank and does a weekly self-test. The local dealer comes every fall and changes the oil and checks it out. It has a self-test/system status screen that you can check yourself. We are in a pretty remote Rural Electric Cooperative region that got set up when FDR was president - and it shows. Don't know what we'd do without it.