The house that we bought a year and a half ago was built in the 1930s, I dont remember the exact year. Anyway, there is knob and tube wiring visible in what used to be the garage (was converted into an entryway/laundry room) and visible in the attic. None of the outlets, except for those in the kitchen have three prongs, so I am assuming they are not grounded. The outlets in the laundry room will flip the breaker if I run both the vacuum and the washer or dryer at the same time. I guess my first question is, Is this a safety hazard or could the visible knob and tube have been replaced but just left on the walls/ceiling? Also, would it be worth replacing the electrical system in the house, as I assume it will cost around 10 to 20 thousand dollars to replace it. Would we ever see our investment returned in resale value, or should we just get it replaced and forget about the return on it? Please help! I don't want to be in a house that could be dangerous to us!