Bard 20WA1
Bard 18WH6
Unit depthUnit depthSupply AirReturn AirSupply AirReturn Air20"8"20"12"19.875"7.875"19.875"11.875"32.25"32.375"69.375"69.375"13.5"14.625"1.375"1.625"20.5"20.5"27.5"27.5"Supply AirReturn AirSupply AirReturn Air
OPENING MATCH

Your openings match up but double check the cabinet surroundings. Over time equipment coils have gotten larger for better efficiency and cabinet dimensions have changed.

Match Bard 20WA1 Bard 18WH6 Difference
Unit width32.25"32.375"+0.125"
Unit height69.375"69.375"0"
Supply Air20" x 8"19.875" x 7.875"-0.125" x -0.125"
Return Air20" x 12"19.875" x 11.875"-0.125" x -0.125"
Distance from the top to Supply1.375"1.625"+0.25"
Distance between Supply and Return20.5"20.5"0"
Distance from Return to bottom27.5"27.5"0"
Mismatch Bard 20WA1 Bard 18WH6 Difference
Unit depth13.5"14.625"+1.125"
Unit weight315 lbs305 lbs-10 lbs