Dont break the window with bare hands, try to do it with something else
See if you have a flat tool to pry the window open. If that window is locked as well, then you should just forget off to a not so locked house.
Don't break into the house you'll attract them
Now that it's open, peek your head in and see if it's clear.Make your way in, and unlock the front door (but don't open it) so you got a way out.
Check the other doors quietly, hammer at the ready.
Check the rest of the house carefully.Also can zombies detect by scent in this game?
Check that last room, and then maybe you should set up the establishment as a safehouse.
Drink waterLet's make this a safehouse
Etch a map into the surface of the table, copying the layout of the neighborhood you just explored so you can keep track of things.