Definition
A unit of cooling capacity equal to 12,000 BTU/hour. A typical home needs 2–5 tons, sized by a load calculation — not a rule of thumb.
Why this matters for your home
A ton of cooling equals 12,000 BTU/hr — the term dates back to the cooling power of melting a ton of ice in a day. Residential systems typically range from two to five tons depending on the home.
The right tonnage comes from a Manual J load calculation, not a square-foot shortcut. An oversized unit cools the air fast but shuts off before removing humidity, leaving a home that feels cold and clammy — so we size to the load rather than rounding up.