My parents bought a house that was owned by the "Card" family. They were hoarders, especially of animals, any animal, and they kept them ALL in the house, and never let them out. Bathrooms and closets were turned into animal housing. The purchase occurred approximately 1 year prior to my birth.
Mrs. Card was an alcoholic, and ended up drinking herself to death in the house. When an autopsy was performed, her blood alcohol level was .38. The rest of the Cards moved afterward. Needless to say, my parents got the house for a significant discount.
I never really noticed any activity growing up, but my bedroom was on the first floor. The move to the basement was when the weird stuff started to happen. Up until my 16th year, the basement, which was basically a three-bedroom apartment, had always been rented out because my parents could use the extra income to feed myself and my 3 brothers.
As soon as one of my brothers and I moved down there, we noticed strange occurrences, but nothing major. Light bulbs would only last for a month, batteries would be dead after opening the package brand new. It wasn't until I had a computer that the REALLY active period began.
I had the computer in my room. It was directly to the left of my bed. It was plugged into a surge bar, along with a reading lamp, a printer and a clock radio. I was on the computer quite a lot, but I always turned it off before I went to bed. I started to notice that when I would wake up, my computer was on. I told myself at first that "I must just have forgotten to turn it off last night..." This event happened once a week at first, then it became a nightly occurrence. Eventually, I specifically unplugged the surge bar from the wall before I went to sleep. This tactic worked for about a week.
One night I was sound asleep when I was awoken by the sound of a loud bang. I sat up in bed, obviously wondering what was going on. One second later my computer, reading light, printer and clock radio all came on at the same time. Then I saw a glowing orb about the size of a golf ball float over my bed about chest height (if standing) and go through my bedroom door. At that point my bedroom (overhead) light came on. My bedroom was a bit strange because the light switch was located just outside the door.
I said the Lord's Prayer and went back to sleep. I have since moved away and never experienced anything similar to that in my life.
It is quite possible that an entity was just passing through and was never attached to that house and its past. Although, considering the history you relate, the past lower level energies in that house may have attracted such an entity. If there were also younger people living there, as well as yourself, all of you may well have and unknowingly contributed to the phenomena, and unwanted electrical, energy consumption.
The orb also may not be related, but a separate entity and experience. It is quite possible that a live human being can also drain electrical appliances, batteries and so forth.
Well, at least you are now out and on your own, hopefully with a low electrical utility bill and unaffected light fixtures, computer and appliances.--Abby