New Possible Owner

Hi! I've been thinking about getting 2 chinchillas for awhile now but have some concerns. One is the temperature problem. We do have air conditioning but I know my parents won't let us run it all summer long. So my only thought is the basement which is cool and has a dehumidifier but is an unfinished basement with only 1 window cement floors and rock walls (I live in an old farm house). I just want to make sure they would be comfortable down there and with not a lot of light would they mind that? If they would be okay down there in the summer that would be awesome but In the winter (here's my next question) I would want them in the spare bedroom next to mine so I'm closer to them. But would changing their location from summer to other months make them stressed out? They would still be in the same cage though. Any info would be awesome, thanks!
One more thing if anyone knows. I have an 8 year old Boston terrier who has never had another animal in her home would that make her stressed? I would keep them separate all times but don't want my dog uncomfortable in her own home.