~24,000 BTU / 2.0 ton
Cooling Load
24,000
BTU/hr
2.0 ton AC recommended
Typical Range
2.0–2.5
ton
Equivalent
24.0k
BTU/hr
Equipment Recommendation
Central AC or multi-zone mini-split
How we calculated this
= 24,000 BTU
Rule-of-thumb estimate. For code-compliant sizing, consult a licensed HVAC contractor.
Reference
Quick AC Size Reference Table
Standard estimates for moderate climate, 8 ft ceilings, average insulation. Adjust up 25–30% for hot climates and 10–15% for unusual conditions.
| Home Size (sq ft) | Cooling BTU/hr | Tonnage | Typical Use |
|---|---|---|---|
| 600–900 | 12,000–18,000 | 1–1½ ton | Small home / large condo |
| 900–1,200 | 18,000–24,000 | 1½–2 ton | Condo / small home |
| 1,200–1,500 | 24,000–30,000 | 2–2½ ton | Average home |
| 1,500–2,000 | 30,000–40,000 | 2½–3½ ton | Mid-sized home |
| 2,000–2,500 | 40,000–50,000 | 3½–4 ton | Large home |
| 2,500–3,000 | 50,000–60,000 | 4–5 ton | Very large home |
Learn
Understanding AC Sizing
How many BTUs per square foot?
The whole-home rule of thumb is 20 BTU per square foot in a moderate climate, which puts a 1,500 sq ft home around 30,000 BTU/hr and into 2.5-ton territory.
Tonnage
One ton of cooling equals 12,000 BTU/hr. The name is literal: a ton of ice melting over 24 hours removes exactly that much heat. Contractors quote in tons, spec sheets list both.
Why climate zone matters
A Phoenix summer asks far more of an AC than a Minneapolis one. Outdoor design temperature, cooling season length, solar intensity: all of it moves together. Hot and humid climates get 30% added, hot and dry ones 25%, while cold climates come down 30% and very cold ones 40%.
Humidity is why the two hot options differ. In Houston the AC spends real capacity pulling moisture out of the air; in Phoenix it doesn't, so the same square footage needs a little less.
When to size up
Add capacity for west-facing sunrooms, top-floor units baking under the roof, vaulted or 9-foot-plus ceilings, and poorly insulated spaces. Each runs about 10–15% over the baseline, and each has its own checkbox in the tool. Basements and heavily shaded rooms go the other way and need less.
Oversizing vs. undersizing
Undersize and the AC runs all day without ever catching up on the hottest afternoons. Oversize and it's worse: the unit hits the thermostat setting quickly, shuts down, and repeats, never running long enough to dehumidify. You get a cold room that still feels damp, and the stop-start duty shortens the compressor's life. Size to the recommendation, not one above it.
FAQ
Common Questions About AC Sizing
How do I calculate what size AC I need?
Start at 20 BTU per square foot of conditioned space, then adjust for climate and anything unusual about the space. A 1,500 sq ft home in a moderate climate lands around 30,000 BTU/hr, which is a 2.5-ton AC. The tool runs that math as you type and hands you a tonnage range to shop within.
How many BTUs per square foot for air conditioning?
For whole-home central AC, plan on 20 BTU per sq ft in moderate climates, 25 to 26 in hot ones, and 12 to 14 in cold ones. Room window units run higher (around 25 BTU/sq ft) because they have to account for window and wall losses on their own. For a single room, use the BTU Calculator.
What does AC tonnage mean?
It's cooling capacity, not weight. One ton equals 12,000 BTU/hr of heat removal: the figure comes from how much heat a ton of ice absorbs as it melts over 24 hours. A 3-ton AC removes 36,000 BTU/hr. Residential central systems typically run from 1.5 to 5 tons.
Is it better to oversize or undersize an AC?
Neither. Undersize it and the system can't reach setpoint on the hottest days. Oversize it and you get short-cycling: the AC blasts cold air, hits setpoint fast, and shuts off before it's pulled any humidity out. The room feels clammy, the compressor's extra cycles wear it down sooner, and the bills go up. If you have to round, round down.
Does a basement need less cooling capacity?
Yes. A basement is below grade, so it exchanges heat with cool soil instead of hot outdoor air, and it takes no direct solar gain. We apply a ×0.90 factor to conditioned basement space. Heavily shaded rooms under mature tree cover get the same treatment.
Related Tools
BTU Calculator
Room-level BTU sizing with windows, walls, insulation, and occupants.
↳ 15×15 room · sunny · 2 windows → ~7,500 BTU
HVAC Load Calculator
Whole-home sizing using simplified Manual J methodology.
↳ 2,000 sq ft · moderate → 3–3.5 tons
Furnace Size Calculator
Heating BTU and AFUE efficiency recommendation by climate.
↳ 1,800 sq ft · cold climate → ~80,000 BTU