Manual S

Metrics and Efficiency Ratings - HVAC Costs pillar

Also known as: equipment selection

ACCA Manual S: equipment selection methodology that translates Manual J loads into specific make/model selections at site-specific design conditions.

Manual S is the third leg of the ACCA design tripod (J for load, D for ducts, S for equipment selection). It validates that a chosen heat pump or AC will actually deliver its rated capacity at Ontario's specific 99% winter and 1% summer design temperatures, which differ from the manufacturer's nameplate test conditions. Critical for cold-climate heat pump sizing because nominal capacity at +8.3C is not the same as field capacity at -15C.

See the full Ontario HVAC and home energy glossary or browse the HVAC Costs pillar.