Yes. You get the radiant heat and the insert is not sucking warm air out of your house like a fireplace does. That’ll do to keep YOU from freezing if you stay in the room that contains the insert. But if its cold and the outage lasts a while and your house is decent sized, your pipes that are not near the radiant heat can freeze and you have a mess when it warms up. The fan puts a LOT more heat into the house than just the radiant heat.
So try buying a marine battery or two and keep them charged. That’ll run the insert fan for a few hours per battery (on my insert at least). For longer blackouts, get a device to hook onto your car battery and convert the DC to household electricity and an extension cord (keep your gas tanks fairly full). That lets you run your fan off of gasoline power even when the power is out and your batterys have gone. If you are judicious, you can make a tank last a few days. (And make sure you have windup electrical light. It is almost impossible to get the car and battery stuff hooked up without light. Power always seems to fail at night. Flashlight batteries always seem to fail at the wrong time and then you are searching for batteries in the dark.)
Of course, recharge the battery when the power comes back on.
“So try buying a marine battery or two and keep them charged.”
Good idea.
We’ve had power outages for up to three days in the dead of winter, and our pipes never freeze. Maybe because my husband insulated the pipes.
Grandpa used to trickle a bit of water from one of the faucets, and that worked for him.