Manual S is the ACCA standard for selecting HVAC equipment. Once a Manual J has calculated the heating and cooling loads, Manual S is used to match those loads to real equipment from manufacturer performance data.
The goal is simple but important: choose equipment with the right capacity for the actual loads — not oversized, not undersized.
Oversizing is the most common mistake. A system that's too large will short-cycle, fail to dehumidify, and cost more to operate. A system that's too small won't keep up on the hottest days. Manual S helps avoid both by selecting equipment whose published performance matches the calculated loads.
In Florida, where humidity control depends on equipment running long enough to pull moisture from the air, getting this right is especially important.
Manual S equipment selection is included in our residential HVAC design packages.