Need to size the air conditioning for a classroom? Classrooms pack a lot of people into a modest space, so occupant body heat dominates the load — the base factor is about 24 BTU/sq ft, but the number of students pushes it up quickly. A well-cooled classroom measurably improves concentration and attendance. The calculator below is pre-set to a classroom at 600 sq ft — a classroom that size typically needs about a 1.5 Ton AC (17,424 BTU/hr, 5.1 kW) in a moderate climate. Enter your own area for an instant answer.
🧊 Find the Right AC Size for Your Room — in Tons & BTU
Convert room size (sq ft or m²) to the exact AC tonnage you need — 0.5, 1, 1.5, 2 Ton and up. ACCA Manual-J inspired, in tons, BTU/hr and kW, for the US, UK, Europe, India, UAE, Saudi Arabia & Australia.
🌍 Prefer metric? Switch units here
🏠1. Space Type
📐2. Floor Area & Ceiling
Range: 50 – 10,000 sq ft
Range: 7 – 20 ft
Range: 0 – 50 people
🌍3. Country / Climate
The base factor assumes a 30 °C / 86 °F design day. Change the chip above to match your region.
🧱4. Insulation
☀️5. Sun Exposure
🪟6. Windows / Glazing
➕Advanced loads (kitchen, appliances, exhaust) — optional
Wattage × 3.4 = BTU/hr. e.g. 500 W ≈ 1,700 BTU/hr
For office IT, gym gear, lab equipment
Classroom AC Size by Floor Area
Typical AC tonnage for a classroom with an 8-foot ceiling and average conditions. Heavy equipment, high occupancy, or a hot climate will push these up — adjust those in the calculator:
| Classroom Size | Recommended AC | Approx. BTU/hr |
|---|---|---|
| 400 sq ft | 1 Ton | 11,616 BTU/hr |
| 600 sq ft | 1.5 Ton | 17,424 BTU/hr |
| 800 sq ft | 2 Ton | 23,232 BTU/hr |
| 1,000 sq ft | 2.5 Ton | 29,040 BTU/hr |
Sizing AC for a Classroom — What to Consider
Size for a full class using the occupants field (each person adds ~600 BTU/hr above the base). Quiet operation matters so the AC doesn’t disrupt teaching, and fresh-air ventilation should be planned alongside cooling. The calculator applies the classroom heat-gain factor automatically; use the advanced fields (occupants, equipment, appliances, ventilation) to match your exact space, and remember an oversized unit short-cycles and dehumidifies poorly — right-sizing gives better comfort and lower running cost.
Frequently Asked Questions
What size AC do I need for a classroom? A 600 sq ft classroom typically needs about a 1.5 Ton AC (17,424 BTU/hr) in a moderate climate; scale up or down with your floor area per the chart above.
What size AC does a classroom need? About 24 BTU/sq ft plus a full class of students. A 600 sq ft classroom for ~30 students typically needs around 1.5–2 tons once occupancy is added.
How many BTU per square foot for a classroom? Roughly 24 BTU/sq ft as a starting factor, before adjusting for climate, ceiling height, occupancy, and equipment heat.
To see where cooling capacity comes from, read the refrigeration cycle explained.
Estimates vary by contractor. Compare free quotes from licensed local pros before you commit. Request a quote →
High-efficiency systems may qualify for utility rebates and federal or state incentives. Find current programs at ENERGY STAR & DSIRE.
Figures are reviewed by the Refcon HVAC engineering team using U.S. DOE, ENERGY STAR & ACCA Manual J data. Estimates only — confirm with a licensed pro.