A storm door can be installed by one person. Most storm doors are made from lightweight aluminum and can be bought with pre-installed mounting rails that allow for easy, single-person installation in under an hour.
To install a storm door with one person, first measure the doorway's width at the bottom, middle and top. Then, put the door in place by screwing the rails to the casing face. Take care not to over tighten screws so the door stays in its square. Next, install the storm door's brackets and closer with screws. Make any necessary adjustments to the door sweep.