7500 watts is about 25amps of 240 running at 80%., dont really want to push it much harder than that.
25 amps will get you the boiler, fridge, a couple tvs, some lights, coffee pot, a sump pump, a small/medium size window AC and a few other things.
Keep a few things in mind. The fuel tanks on most generators are sized to run for 8 hours at 50% load. Running it at 80% will increase fuel consumption accordingly. The fuel tank on a 7500watt generator will normally hold 6 to 7 gallons.
That being said, with a 7500 watt generator, you should expect to use a minimum of 5 gallons per 24hr day if you are conservative with it. If you want to run it around the clock figure on around 20 gallons per 24hr day.
I have a 18,500 watt generator, it uses around 2 gallons per hour when running hard. The most i have pushed it is up to 43 amps per leg which is around 10,500kw. I was cooking on the electric stove and washing and drying laundry, tv was on and so were most of the lights.
My plan for the future is to pick up a Honda EU3000. It will run almost 21 hours at 1/4 load on 3.5 gallons of gas. It will run just over 7 hours running hard.
The plan is to install them both and primarily run the Honda to conserve gas but have some level of comfort. Then an hour or two in the AM and PM start up the big boy and do laundy, dishwasher, etc.
The moral of the story is to be sure and balance fuel consumption against your actual 'needs' before you purchase a generator.