the US power grid is not in any way unreliable. US residents enjoy some of the highest grid availability figures for anywhere in the world. Sure, sometimes things go horribly wrong but their system is not unreliable by design as this comment insinuates.

I live in a rural part of New England with an electricity company that everyone dislikes because it's super expensive and sometimes things go bad. Since 2010 we've had the following major outages:

* October 2011 Snow Storm - Lost power for 4 days, didn't end up being that cold

* October 2019 Thunderstorms - Lost power for 3 days, thankfully generator kept the house going

* August 2020 Tropical Storm Isaias - Caused widespread grid damage, but only lost power for 18 hours. Internet was out for 36 hours.

* August 2021 Hurricane Henri - Widespread grid damage, lost power for about 6 hours. By this point I had powerwalls. I didn't even turn down the air conditioner.

That's it - every other outage has been a few hours. And that's living in a rural area that is heavily wooded with most of the power lines above ground and often long runs close to trees. If I lived in a suburb or city those times would be even less.

The grid in the United States, despite some widespread and documented regional failures (2021 Texas, 2003 NE Blackout), is remarkably resilient.

I would say it depends on where you live. The grid in CA has (in some parts) not been reliable for 5+ years. To Chris' point below though, it's not really relevant because gas furnaces need electricity to operate, too.

A common misconception is that you can use your forced air furnace when the power is out - you can't because the blower relies on electricity to move air around. Your point on the cloud service is a good one, which is why cloud services are value-add but unnecessary for core system functionality, ie your system works if there's no internet.

In California power outages are very frequent (PG&E is now cutting off the residential power upfront, to avoid fires and associated liability).

I’ve experienced 4-5 outages last year, a couple were local, a couple were widespread. One lasted 2 days.

Fortunately I do have a small 3.2kWh battery backup power, so I can keep the refrigerator from defrosting. I do think that this is sufficient to power the air furnace as well, but I haven’t tried.

The residential internet outages also are pretty frequent, but we don’t notice these as much as power outages.