A little background info follows first for my question: Have a 80 year old house, had electric updated in 1980, circuit breakers, more power brought into house, outdoor outlets and power outlets in laundry, kitchen area. We have an antique combo tandem/parallel
obsolete outlet,which is single plug. I now notice the other outlets in the living room are T-slot outlets (update of the tandem parallel outlet) these can still be purchased for replacement only thru Leviton, model#5000-1. They are not grounded, don't know if box is grounded....so I assume these obsolete tandem parallel outlets were at some point updated to the T- slot outlets. There are additional T- slot and 2 and 3 prong regular outlets in the rest of the house. I am assuming those T-slot outlets were updated from the obsolete tandem/parallel outlets, my ****** research said the T-slot outlet is the more modern update of the tandem/parallel outlet. I spent a lot of time ****** identifying these obsolete plugs and along the way picked up this info.
I have lived here for 35 years and have used the outlets with no problem.
Here is my question:
I want to install a 12,000btu window a/c using the obsolete parallel tandem outlet ( only outlet near widow where a/c will be). Since I have researched and discovered it is obsolete should I replace it with a T-slot outlet or gfci outlet, or a 2 or 3 prong regular plug? I am assuming since the outlet is obsolete it should be changed, And with the electrical load of the a/c I want to be safe.
Would it be better to have a direct line to the circuit breaker box installed? It's own dedicated circuit, line?
How expensive would it be to have this done?
Thank you for any help.