How do you safely produce indoor heat during power outage?

generally, you don't. what you do is put more clothes on.

Using candles for light is ok -- but more burning of anything inside the house is very dangerous -- carbon monoxide builds up and its lethal.

Propane heaters, generators, and anything else that burns fossil fuels MUST be kept outside.

If it becomes so severe you can't stay ... evacuate to a shelter. do NOT burn stuff to keep warm.

[Exception: properly designed and installed wood stoves and fireplaces can be used with the damper OPEN to exhaust fumes. Yes, this lets heat escape. Yes, it also saves your life from carbon monoxide poisoning.]

an emergency generator to run the things you need to stay on.

Do you have gas service? If so, buy an old style space heater.

I have an outdoor wood-fired boiler and a backup generator for the circulators and the oil furnaces. Many of my neighbors have wood- or pellet-fired parlor stoves indoors, although the pellet stove may need a battery backup option. We also have a gas-powered fireplace in one room that uses no electricity.

Three dog night.

Camping supply stores have Coleman powered or Propane powered heaters for use in camping. I have a wood stove that I love using in the winter, even when the power is on. Good luck.

You could buy a propane in tent camping heater. Run your oven if its a gas unit. Buy a wood stove on a hearth.

Use a gas log fireplace. If you have an electric range turn on the oven. If you have a gas furnace, it is possible to burn gas and let the warm air rise without having a blower fan. Talk to your service man about that.