I have one upstairs bedroom that is consistently cooler than the other two
bedrooms. The two warmer rooms are over the garage. A friend of mine
mentioned that this might be fixed by balancing the a/c. I have zoned a/c so
any changes shouldn't affect the downstairs rooms.

I asked my a/c guy about balancing and he asked if I had the cfm ratings for
each room; apparently this is on the blue prints for the house which I don't
have. I am pretty handy and I was wondering if the balancing could be done
without the cfm room ratings. How do you go about balancing the a/c?

Thanks in advance for any suggestions.

Mark