Did you know that from April 1 to October 30th, inclusive, your rentals must have both window screens and screen doors? Here’s the relevant bit of the sanitary code about doors:
410.552: Screens for Doors The owner shall provide a screen door for all doorways opening directly to the outside from any dwelling unit or rooming unit where the screen door will be permitted to slide to the side or open in an outward direction, provided, that in an owner-occupied unit, the owner need provide screens only for those doorways used for ventilation [further details about mesh size etc. omitted].
That’s pretty clear: you need them for all doorways. The only exception is if you are an owner-occupy. Then you need to check yourself against the minimum standard for ventilation. In habitable rooms (not dedicated hallways), owner-occupiers need to either mechanically vent the room or provide a screen window or door. You must have at least some ventilation in each room. Non-owner occupiers need screen doors, period.
Here’s the part that says when they are required:
410.553: Installation of Screens The owner shall provide and install screens as required in 105 CMR 410.551 and 410.552 so that they shall be in place during the period between April first to October 30th, both inclusive, in each year.
Read more at 105 CMR 410.
How to Install a Screen Door
According to Home Depot’s article, How to Install a Storm Door, this project requires intermediate skill and roughly one-third of a day. An experienced hanger can probably do the job in under 90 minutes. It all depends on whether there was a door fitted before, whether you have an old house with surprises in store, and whether you have a second pair of hands. Some retailers like Home Depot and Lowe’s offer installation. When in doubt, call a pro! It’s a depreciable business expense (check with your accountant).
If you already have screens on your door but they’re torn, you can replace all the broken screens in less than an hour with cheap supplies from your local hardware store. Watch this detailed YouTube video on How to Replace a Window Screen to see how it’s done.