By Anne Fonda
BTUH (or BTUh) stands for British Thermal Units per hour. A British Thermal Unit (BTU), measures how much heat energy it takes to raise or lower one pound of water by one degree Fahrenheit. BTUH measures how much heat a furnace can produce in an hour, or how much heat energy a cooling unit can remove from the air space in one hour.
BTUH is expressed in BTUs when discussing an HVAC unit’s capacity. A typical furnace will have 60,000-100,000 BTUs. The higher the BTUs, the more heating capacity the furnace can deliver.
For cooling systems, including central air conditioning, heat pumps, and multi or mini-split systems, BTUs are commonly expressed in tons. The tons, or tonnage of an AC unit refers to how much heat it can absorb and remove from the air in your home.
The term comes from the 1800s and early 1900s when people (at first only the wealthy) would order a ton of ice to cool food. The ice would be placed in ice boxes or stored in ice houses. Today, an AC unit’s capacity rating is the equivalent tonnage of ice's heat-absorbing ability in 24 hours.
One ton of cooling = 12,000 BTU/h
Understanding all of these terms can help you figure out what size AC unit you need. A trained HVAC professional can provide you with precise HVAC sizing for your home. The table below can give you an ballpark idea, based on the square footage of your home.
| Home size (sq. ft.) | Unit Size (tons) | Unit Size (BTUs) |
| 1000 sq. ft. | 2-ton AC unit/2-ton heat pump/2-ton mini split | 24,000 BTUs |
| 1500 sq. ft. | 3-ton AC unit/3-ton heat pump/3-ton mini split | 36,000 BTUs |
| 2000 sq. ft. | 4-ton AC unit/4-ton heat pump/4-ton mini split | 48,000 BTUs |
| 2500 sq. ft. | 5-ton AC unit/5-ton heat pump/5-ton mini split | 60,000 BTUs |
Cooling units also come in half-ton sizes - for instance, a 2.5-ton AC unit or heat pump would be equivalent to 30,000 BTUs, and a 3.5-ton AC unit would be equivalent to 42,000 BTUs. It’s important to get a system that is sized correctly for your home.
An improperly sized HVAC system can create problems with energy consumption and your overall comfort in your home. Working with an HVAC professional can help ensure that you get the right system for your home. Contact your local American Standard dealer for a quote.
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A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Kimberly Sexton, Senior Systems Engineer
BTU, or British Thermal Units, are how to measure the amount of heat required to raise or lower one pound of water by one degree Fahrenheit, and can help determine the right size system for your home.
Discover what ton means in HVAC for your central AC unit, and why it matters. Depend on American Standard for your cooling needs.
HVAC capacity is the output or production capability of a piece of heating or cooling equipment. Central air conditioning capacity and heating capacity are measured in tons or BTUs.
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