Hello, I am being proactive about replacing one of our AC units due to the fact that it is R22 and I know it will be an issue in the coming years. I'm fairly certain our current unit is original to the house (1978). The house is dual zone, and the one I need to replace is for the upstairs. We have had no issues with the current unit's performance, but I have had to put about a pound of Freon into it every few years. The handler is in our attic, so I'd rather get this done in fall or spring and not when it breaks down mid summer, when it's too hot in there for someone to safely work. I have received a couple quotes, and my questions are this: 1.) Any main differences of quality between Carrier and American Standard? Does one strongly stand out besides the other. 2.) We were quoted for Seer 13. I know from what we currently have, there will be fair savings. We don't have any intention of moving, is it worth paying more for a higher Seer? Our electric bill in the summer is ~$100-$150. 3.) Seeing as this is the first time I'm replacing an AC unit, anything else I should be taking into consideration? Any insight is much appreciated - thank you!