Total newbie to AC systems. Where should I go for basic overview of issues, terms, ratings, etc? We are looking at putting AC into second floor addition currently under construction. Only window units currently. Should we put AC only in upstairs (bedrooms) or put in first floor as well. We don't use AC all that much, prefer open windows so won't need cadillac system. Neighbor suggested high velocity system. Worth it? Issues, comparisons with traditional? Heat is hot water radiators so no central air option. Basement is open ceiling and room for air handler but also attic space. Chicago suburbs. 1800SF cape cod house. Thanks!