We use essential local storage for app functionality, optional analytics (Google Analytics), and error monitoring with session replay (Sentry). No traditional cookies. Privacy Policy
Estimate the cooling capacity required for a space. Enter a ZIP or state to set the climate factor automatically from the IECC zone, then combine with insulation and occupant load.
Estimate the cooling capacity required for a space. Enter a ZIP or state to set the climate factor automatically from the IECC zone, then combine with insulation and occupant load.
Switch to Advanced to tune the hidden parameters.
This calculator applies general code rules that vary by jurisdiction and code edition. Confirm the code edition adopted in your area and verify with the authority having jurisdiction (AHJ) before installation. Use at your own risk. Read full terms.
A rough rule is 20–25 BTU/hr per square foot, so a 1,000 sq ft home lands around 20,000–24,000 BTU/hr, or about 1.5–2 tons. Hot climates, lots of west-facing glass, or poor insulation push it higher. This is a starting estimate only — an oversized AC short-cycles and will not dehumidify, so confirm with a Manual J load calculation.
Yes. An oversized AC cools the air quickly but shuts off before it removes enough humidity, leaving the house cold and clammy and short-cycling the compressor (which shortens its life and wastes energy). Right-sizing from a Manual J load calc — not from square-footage rules of thumb — gives longer run times and far better comfort and dehumidification.
A 2-ton (24,000 BTU/hr) unit typically cools roughly 900–1,300 sq ft in a moderate climate with average insulation. The range is wide because ceiling height, window area, sun exposure, and air-sealing all shift the load — use it as a sanity check against a Manual J result, not as the basis for selecting equipment.