Glossary
Sizing & airflow
Tonnage
An air conditioner or heat pump's cooling capacity. One 'ton' equals 12,000 BTU per hour, a reference to the melting power of a literal ton of ice per day. Residential systems typically run 1.5 to 5 tons.
Why it matters for your home
Bigger is not better. An oversized AC cools the air fast, then shuts off before dehumidifying, the classic clammy St. Louis house in July. The right tonnage comes from a Manual J calculation on your home; replacing 'like for like' just repeats whatever sizing decision (or guess) was made decades ago.
Related terms
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