Is there any way to allow having a cleaning lady work in my house if I’m there alone? What if the window shades or door are open?
It is an issue of Yichud. However, if your wife can come home at any moment, referred to as Yotze V’nichnas, then it is OK.
Likewise, according to many Poskim, if others have the key and can come in unexpectedly it is also OK. However, both of these Heteirim have certain limitations – see in the link below.
Another solution would be to have the door to the street (or to the hallway in a building) open so that others can enter unexpectedly. This applies if it is normal for people to do so.
However, in the latter solution, it only helps if you sit in the room closest to the door.
ראה מנחת איש פרק כ.
See here as well: