As others have said, managing this sort of human interaction is part of growing up. And often a module in the Some People Will Always Be Dicks 101. I wouldn't fret, it's a lesson that everyone should learn sooner rather than later.
I was a student in the 1990s, and as it was Liverpool, no one had got around to discovering central heating. Hence those big electric bar heaters, each one requiring the output of a modest soviet-era nuclear plant. Upon turning off, the residual heat had a half life measured in milliseconds. Running a brace of those all evening turned out to be expensive so we got the landlord to provide one of those gas heaters. That used to make us sleepy. The eventual solution was to go to the pub. It was either that or get the Royal Mint to churn out enough 50ps to keep the meter turning. The two houses we stayed in had meters and, in theory, there was pot of fifty pence pieces we all contributed to with some agreed amount each week. The jar was helpfully labelled 'emergency beer fund.' Honestly, it was cheaper to go the pub and buy a couple of pints each than keep those leccy heaters running.
And yes, we had that flatmate, the one who didn't pay his bills. Any bills. He was always about to. Every now and again he'd give us some random sum of money to pay off part of his rent and utility debts. Anyway, the first year he (or rather his parents) settled everything at the end of term. The second year he got worse and ended up owing us a significant amount (for students in the 90s anyway) and we figured as it was the final year, he'd disappear and we'd never see a penny. So, while he was away one weekend (undoubtedly to persuade his long-suffering girlfriend to lend him some cash), we took everything he owned. Which turned out not to be much. So, with the help of our other housemate's slight crazy parents, we hired a van, drove to his house in Cheshire and, by telling his parents that we were helping him move into his girlfriend's for the summer, literally took not just everything he owned, but everything he'd ever owned.
Then we ransomed it back, with proper cut-out-of-newspaper notes and everything. He called the police and, I'm not joking, they came around. And laughed. Brilliant lads, brilliant. Which was great (other than for Jo, as she was definitely not a lad and it was really her idea). Eventually, we met his parents on windswept Southport bench and swapped cash for a van-load of his stuff. He didn't turn up and we, unsurprisingly, never kept in touch.
When I did my PhD and the two other very brief house shares I've been in, it's always been the equal split and everyone has been fine over it. Life is too short to worry about people using hairdryers and stuff and not everyone is a dick.