I got into alot of houses with single zone systems with multiple floors and about 90% of the time I get complaints that the upstairs is always much warmer than downstairs. If they have them I usually set volume dampers (if they're not broken) but in many cases customers don't have them. More and more I've been telling customers to block off the lower portion of the return air grilles on the main floor in an attempt to increase return static pressure and cause the upstairs return to draw more stratified air. Is this a good suggestion or am I being a complete idiot? Thanks