Free Tool
HVAC Sizing Calculator (Manual J Lite)
Right-sized HVAC is the
Estimate your HVAC tonnage
0 tons
Frequently Asked Questions
Why is HVAC sizing so important?
An oversized system short-cycles, fails to dehumidify, and wears out faster. An undersized system runs constantly and never reaches setpoint. Right-sizing is the single biggest comfort and efficiency factor.
Is this calculator a real Manual J?
No — a true ACCA Manual J calc accounts for window orientation, infiltration, and duct losses. This estimator is for budgeting and contractor-comparison only. Always ask your contractor for a real Manual J.