Do you want to move into the house in winter with flowers with closed balconies?

It depends on what flowers are on your balcony! If you don't have a cold tolerance, you can move it indoors! If it's hardy, there's no need for it!

After heating, open the door to the balcony regularly, so that the balcony maintains a certain temperature, and after entering the nine, use a suitable plastic bag to cover the flowers at night and remove them during the day, and the general flowers will not have a problem.

Or make a frame and cover it with plastic sheeting to keep the plants safe for the winter. But remember, don't have too much water in the pot to prevent frostbite on the roots. Every time you water in the middle of the day when there is sunshine, spray water as well.

Unless we have tropical plants here, the general flowers are not so afraid of the cold, so they don't need to be moved. But I don't know where you are, if it's a cold area such as the northeast and northwest, you might as well move.

It depends on what kind of flower, some plants can overwinter naturally, generally plants need a certain temperature to safely overwinter, if the balcony is closed, you don't need to move indoors, if it's not closed, you need to move indoors.

If it is a flower that uses a water-soluble fertilizer of Falat amino acids, the cold resistance will be greatly enhanced.

Yes, but it can be properly ventilated, and it will freeze to death if it is too cold.