With that kind of investment I'd highly recommend a back up generator. The bad news of this is that cheap generators and proportional controls (I am not 100% sure of helix but herpstats absolutely) don't play well together (anything other than PURE SINE WAVE can cause the thermostat to 'stick' wide open and cook the collection) I know Honda are pure but I am not sure about others most are modified sine wave which is questionable.

sorry for that one but I believe it is prudent unless you live someplace warmer than I do!