BTU, tonnage and HVAC terms without a sizing shortcut

Convert heat-flow units and understand common terms while leaving home equipment sizing to a reviewed calculation.

BTU per hour describes a rate of heat flow. One refrigeration ton equals 12,000 BTU per hour in the NIST conversion reference. A conversion changes units; it does not calculate the heating or cooling load of a home.

SEER2 and HSPF2 describe seasonal cooling and heating efficiency under specified tests. AFUE describes fuel-heating efficiency. Compare equivalent test metrics and exact system combinations rather than treating a brand or one outdoor unit as a complete match.

AHRI references identify tested combinations; a reference is not a home suitability approval. Use the converter for a documented capacity, then keep the original source and units. Floor area, vent counts and a label alone cannot establish the capacity your project needs. Your assessment should lead to a reviewed load calculation and technical match.

Sources you can check

• NIST SI conversion factorsNational Institute of Standards and Technology · checked 2026-09-28
• Heat pump efficiency metric definitionsENERGY STAR · checked 2026-09-28
• Furnaces and AFUEENERGY STAR · checked 2026-09-28
• AHRI certified indoor / outdoor matched systemsAir-Conditioning, Heating, and Refrigeration Institute · checked 2026-09-28

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Keep the equipment labels and supporting documents in one home passport, or explore costs using your own quotes. This public website is a browser-local planning preview; no live AI diagnosis, installation booking, order or notification is performed.