Battery Backup question

[matt.thompson05@gmail.com]

Has anyone installed a battery backup on either their whole house electrical panel, or on a propane/gas fueled radiant heat system?  We're looking at Tesla Powerwall, but it's very expensive and there is an added cost due to our 400 amp electrical meter.  We have a plug-in whole house generator, but we would ideally like to have an automatic backup up the heating system (which requires VERY little electricity) and possibly the well pump.  Thanks!