About ThermoMath

ThermoMath is a free collection of HVAC calculators for homeowners, contractors, and students. Every calculation runs in your browser — no account, no login, no data sent anywhere.

The tools cover the most common sizing and estimation tasks: cooling and heating load, AC and furnace sizing, duct sizing, airflow, SEER savings, and running cost.

Sizing calculators use industry rule-of-thumb formulas. Airflow and energy calculations follow standard methodology. All results are estimates suitable for planning and budgeting, not a substitute for a Manual J load calculation or a licensed professional.

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