This is an outlet that costs a lot of money, and saves you and your expensive hairdryer from burning up real crispy. Essentially it is a hair trigger fuse in your electrical circuit that cuts the power to whatever is plugged into it or anything downline from it. It must be installed at the beginning of the circuit for it to protect outlets besides the one it is installed in. In your case, I would still hire an electrician, so that he can make sure you get the maximum protection from this option. If you don't install the GFI outlet correctly, you will not protect any outlet but that one. The outlets will still not be "grounded" and should be marked as such. Better than nothing, and cheaper than rewiring the whole stinkin house.