The old fireplaces actually heat much much better than new ones. The new ones are designed for safety, they a small, high off the floor and very deep, and do not heat much at all. They are designed to send the heat up the chimney to protect the house. They are just decorations. Older fireplaces - the fire is at floor level, the firebox is shallow and the opening usually quite large and many have a smoke shelf built in that holds heat. The chimney is also built up through the middle of the house, so the heat going out the chimney is not wasted.
We sometimes keep fires burning in our two fireplaces for weeks at a time and it heats 70% of the downstairs ranging form 80 degrees into the low 70s or high 60s. The second floor is heated to about high 50s/low 60s from the chimney passing through. There is some danger of course, but the house has not burned down in the past 180 years, not likely to change that today.
It was funny to see the little pile of sticks after reading the other post. Not making fun of you, just at perceptions of people who have never burned wood for heat. We do not heat with the fireplaces all winter, just on and off as we feel like it. Still, we got through 1-3 cords of firewood each year. If you cut up those sticks, you might have 1/10 of a cord. However those limbs are too small to be of much use in a fireplace. They are too small and will burn very fast (generating lots of heat, but you will be constantly feeding more in. You are not gong to throw four of those into a fire and get 3/4 of the way through a night before someone has to add more. You would be lucky to get 15 -20 minutes. Hardwoods like oak, ash and maple burn more slowly, but if they were that small, they would not be dense enough to slow the burn time much.
I will attach a picture of a cord of wood for reference. People I know who heat with wood entirely put away 7-8 cords for the winter.