This is probably fairly mundane, but I'm really stumped as to whether I'm in the wrong here. A bit of background, first: I'm a second year university student living in a five bedroom house with four other flatmates, and we all get along reasonably well with each other. I have the ground floor bedroom, which is the largest, but also the coldest, due to it being at the front of the house with large bay windows. The past few months have usually been colder than usual, so I'll take it upon myself to turn the boiler on for some heating in my room if it ever gets too chilly. 

However, a few weeks ago, one of my flatmates (let's call him Elvis) confronted me after I made a passing comment about what I usually set the boiler dial at. He said that I was being selfish for turning the boiler on, and that I was the sole cause of this heating issue. I suggested that he just turned his radiator off in his room if he was too hot (every room has its own radiator that can be turned on or off independently), but he told me that he already does, and that heat was rising from the bottom floor to the top floor. We eventually came to the compromise that we would keep all of the radiators off, except mine, to minimise the temperature elsewhere in the house.

(Another flatmate told me that it's annoying to turn off the radiators individually, because then they take even longer to warm up when he wants the heating on. I said that it was selfish that he'd rather have his heating come on faster when he wants than let me have my radiator turned on independently, but that's another matter.)

However, even since we compromised, he'll still turn the boiler off whenever he's nearby. We've not spoken to each other about this, but we'll often end up in anonymous boiler proxy wars. I don't turn the heating on all of the time, but I will whenever my room does get particularly cold, and he'll consistently come to turn it off. Last night it was two degrees Celsius outside, and he came downstairs to turn it off each time that I turned it on (this happened about several times).

I've never seen Elvis wearing something other than shorts, even throughout all of winter, so he's definitely a naturally warm person - I understand that if he's getting too hot in his room, it must be as frustrating to him as it is when I'm too cold. However, I really struggle to understand how turning the boiler off will make any difference when his radiator (and most others in the house) is turned off; the flatmate in the room directly above mine has said that he has no issues with being too hot, so I don't think it's an issue with heat rising from my room specifically. And it's not like I'm trying to keep the house at insane temperatures - the boiler has a dial with ten notches on it, and I never turn it past the third mark. Even when it's ten or eleven degrees outside, I feel as though it's warranted to keep some heating on.

So, I want to know, am I the asshole here? What should I do?