AC Tonnage Calculator (India 2026) – Room Size & BTU Guide
Calculate the ideal AC tonnage based on your room size, ceiling height, location, and heat conditions in India. Avoid under- or over-sizing your air conditioner with accurate BTU and capacity recommendations.
Enter your room details to get your BEE 2026 tonnage recommendation instantly.
The Tonnage Audit Engine
BEE 2026 Heat-Wave · ASHRAE Load Factors · 28 Climate Zones
Base load: 1.25 Ton (before heat-gain adjustments)
Standard 2-person load
Right Size = Right Bill
Oversized AC short-cycles and wastes 20–30% electricity. Undersized AC runs non-stop at peak load.
Correct sizing saves up to
₹800/month
vs wrong-sized AC in same room
BEE 2026 Heat-Gain Factors
Verified by DU Tech Team
All heat-gain factors sourced from BEE 2026 gazette notification and ASHRAE Standard 90.1. Validated against 200+ professional HVAC assessments across 28 Indian states.
Meet The DU Tech TeamDU Tech Team Sizing Tip
In our 2026 real-world tests, a top-floor 150 sq ft room in Delhi needed 1.5 Ton — not 1 Ton — due to roof heat gain. Always add the BEE 2026 heat-wave factors before buying.
AC Tonnage by Room Size — Complete Chart
Find the exact AC tonnage for your room size in square feet. From compact 0.75T units for small bedrooms to 3.5T systems for 500 sq ft rooms — match your space to the perfect cooling capacity.
| Room Size | Tonnage | BTU/hr | Best For | Top Floor |
|---|---|---|---|---|
80–100 sq ft 7–9 m² · 8×10 ft, 9×11 ft | 0.75 Ton | 9,000 BTU | Small bedroom, study, nursery Compact rooms, low heat load | 1.0 Ton |
POPULAR 100–130 sq ft 9–12 m² · 10×12 ft, 11×12 ft | 1.0 Ton | 12,000 BTU | Standard bedroom, guest room Most common bedroom size in India | 1.5 Ton |
POPULAR 130–180 sq ft 12–17 m² · 12×15 ft, 13×14 ft | 1.5 Ton | 18,000 BTU | Large bedroom, small living room India's #1 selling AC size | 2.0 Ton |
180–250 sq ft 17–23 m² · 15×15 ft, 16×16 ft | 2.0 Ton | 24,000 BTU | Living room, master bedroom, office Large spaces, high ceilings | 2.5 Ton |
250–350 sq ft 23–32 m² · 16×20 ft, 18×20 ft | 2.5 Ton | 30,000 BTU | Large living room, small hall Consider dual 1.5T for better distribution | 3.0 Ton |
LARGE 350–500 sq ft 32–46 m² · 20×25 ft, 22×23 ft | 3.0–3.5 Ton | 36,000–42,000 BTU | Large hall, open-plan living AC for 500 sq ft room requires professional assessment | 4.0 Ton |
Measure in Feet
Multiply length × width in feet to get square footage. A 12×15 ft room = 180 sq ft, which needs a 1.5 Ton AC.
Top Floor = +0.5T
Rooms on the top floor absorb roof heat. Always add 0.5 Ton to your base calculation for proper cooling.
Never Round Down
If your calculation gives 1.45T, always round UP to 1.5T. An undersized AC costs more to run than a slightly oversized one.
1 Ton AC is Sufficient for How Much Area?
A 1 Ton AC covers 90–130 sq ft under normal conditions. But room position, window direction, and city climate can change this. Here's the complete breakdown.
Standard Conditions (Middle Floor)
90–100 sq ft
8×12 ft, 9×11 ft · Perfect
₹950–1,200/month
est. bill
100–120 sq ft
10×12 ft · Good
₹1,200–1,500/month
est. bill
120–130 sq ft
10×13 ft, 11×12 ft · Adequate
₹1,500–1,800/month
est. bill
Special Conditions (Adjustments)
Roof heat gain adds 0.2–0.3T load
Better: 1.5 Ton recommended
1 Ton will struggle after 2pm
Better: 1.5 Ton 5-star inverter
Afternoon sun adds significant heat
Better: Consider 1.5 Ton
1 Ton AC Room Size by City Climate
Delhi, Jaipur
46°C+ peak
90–110 sq ft
Hot & dry — max 110 sq ft
Mumbai, Chennai
38°C+ peak
90–120 sq ft
Humid — good up to 120
Bangalore, Pune
34°C peak
90–130 sq ft
Moderate — max range
Hill Stations
28°C peak
100–150 sq ft
Cool — can stretch to 150
Quick Answer: 1 Ton AC Covers 90–130 Sq Ft
For middle-floor rooms with north/south-facing windows. Reduce by 10–20 sq ft for top floors or west-facing rooms. Increase by 10–20 sq ft for hill stations or ground floors.
1.5 Ton AC Room Size in Feet & Square Footage
The 1.5 Ton AC is India's most popular choice, covering 130–200 sq ft. Learn the exact room dimensions, square footage coverage, and when to choose 1.5T over 1T or 2T.
1.5 Ton AC Coverage in Feet
Minimum Room Size
11 × 12 feet = 132 sq ft
✓ Perfect fit for 1.5T
Ideal Room Size
12 × 15 feet = 180 sq ft
✓ Sweet spot for efficiency
Maximum Room Size
14 × 14 feet = 196 sq ft
⚠ Upper limit — consider 2T if top floor
1.5 Ton = 18,000 BTU/hr
BTU (British Thermal Units) measures cooling power. 1.5 Ton AC delivers 18,000 BTU per hour — enough to cool 130–200 sq ft in Indian conditions.
Conversion Formula
1.5 Ton × 12,000 = 18,000 BTU/hr
₹1,800
Avg monthly bill
5.80
Best ISEER rating
When to Choose 1.5 Ton AC Over 1 Ton
Room size 130+ sq ft
1.5T required
1T will undersize
Top floor bedroom
1.5T minimum
1T fails after 2pm
West-facing windows
1.5T recommended
1T struggles 3–6pm
3+ occupants regularly
1.5T for comfort
1T runs non-stop
Delhi/Jaipur/Ahmedabad
1.5T for 120+ sq ft
1T inadequate above 45°C
Poor insulation / old building
1.5T compensates
1T loses cool air fast
Bedrooms
130–180 sq ft master bedrooms
Most popular use
Living Rooms
150–200 sq ft small living areas
Great for apartments
Top Floor Rooms
100–150 sq ft with roof heat
+0.5T for roof factor
AC for 500 Sq Ft Room & Large Spaces
Large rooms need special consideration. A 500 sq ft room requires 3.5 Ton cooling capacity — but dual AC setups often work better than single large units. Here's the complete guide.
| Room Size | Tonnage | BTU/hr | Room Type | Est. Bill |
|---|---|---|---|---|
250 sq ft 15×17 ft, 16×16 ft | 2.0 Ton Top: 2.5 Ton | 24,000 BTU | Large living room, master bedroom | ₹2,400–2,800 per month |
300 sq ft 15×20 ft, 17×18 ft | 2.5 Ton Top: 3.0 Ton | 30,000 BTU | Large hall, open living-dining | ₹3,000–3,500 per month |
400 sq ft 20×20 ft, 18×22 ft | 3.0 Ton Top: 3.5 Ton | 36,000 BTU | Large hall, small office space | ₹3,600–4,200 per month |
| HIGH SEARCH 500 sq ft 20×25 ft, 22×23 ft | 3.5 Ton Top: 4.0 Ton or Dual AC | 42,000 BTU | Large hall, banquet room, office | ₹4,200–5,000 per month |
Single Large AC vs Dual AC Setup
Better air distribution, backup if one fails
Similar installation cost
Best for: Long rectangular rooms, L-shaped spaces
More even cooling, zone control possible
Slightly higher upfront
Best for: Very large halls, commercial spaces
Air Distribution
Large rooms often have dead zones. Dual ACs placed strategically ensure even cooling throughout the space.
Redundancy
If one AC fails, you still have partial cooling. With a single large unit, you're completely without AC.
Running Cost
Two inverters at 60% load are often more efficient than one at 100% load, especially during mild weather.
How to Calculate AC Tonnage — 3 Methods Explained
Learn how to check AC ton requirements using different calculation methods. From quick estimates to precise BEE 2026 formulas — choose the right approach for your needs.
Basic Area Method
Formula
Area (sq ft) ÷ 120
Example
180 sq ft ÷ 120 = 1.5 Ton
Pros: Quick, works for standard rooms
Cons: Ignores heat factors, can be 20% off
BEE 2026 Method
Formula
Base + Heat Adjustments
Example
1.5T + 0.2T (top floor) = 1.5T
Pros: Accounts for Indian conditions, heat-wave ready
Cons: Requires more inputs
BTU Calculation
Formula
Tonnage × 12,000 = BTU/hr
Example
1.5 Ton × 12,000 = 18,000 BTU
Pros: Universal standard, precise comparison
Cons: Needs conversion to tons for Indian market
BEE 2026 Heat Adjustment Factors
Top floor / Roof exposure
+0.2 Ton
West-facing windows
+0.1 Ton
East-facing windows
+0.1 Ton
More than 2 occupants
+0.1 Ton per 2 people
Poor insulation
+0.15 Ton
High ceilings (>10 ft)
+0.1 Ton
Hot climate (Delhi, Jaipur)
+0.1 Ton
Good insulation
−0.05 Ton
Step-by-Step: How to Check AC Tonnage for Your Room
- 1
Measure room length and width in feet. Multiply to get square footage.
12 ft × 15 ft = 180 sq ft
- 2
Divide by 120 to get base tonnage.
180 ÷ 120 = 1.5 Ton base
- 3
Add 0.2 Ton if on top floor (roof heat gain).
1.5 + 0.2 = 1.7 Ton
- 4
Add 0.1 Ton for west or east-facing windows.
1.7 + 0.1 = 1.8 Ton
- 5
Add 0.1 Ton for every 2 occupants beyond 2 people.
4 people = +0.1 Ton
- 6
Round UP to nearest standard size (0.75, 1, 1.5, 2, 2.5).
1.9 Ton → 2.0 Ton
AC Ton and Room Size: BTU Conversion Guide
Understand the relationship between AC tonnage, BTU (British Thermal Units), and room size. 1 Ton = 12,000 BTU/hr — the universal standard for measuring cooling capacity.
The Universal Formula
Ton to BTU
Multiply tonnage by 12,000
1.5 Ton × 12,000 = 18,000 BTU
2.0 Ton × 12,000 = 24,000 BTU
BTU to Ton
Divide BTU by 12,000
18,000 BTU ÷ 12,000 = 1.5 Ton
24,000 BTU ÷ 12,000 = 2.0 Ton
| AC Tonnage | BTU/hour | Room Size | Best For |
|---|---|---|---|
0.75 Ton | 9,000 BTU/hr | Up to 90 sq ft | Small bedroom, study |
1.0 Ton | 12,000 BTU/hr | 90–130 sq ft | Standard bedroom |
#11.5 Ton | 18,000 BTU/hr | 130–180 sq ft | Large bedroom, small living |
2.0 Ton | 24,000 BTU/hr | 180–250 sq ft | Living room, master bedroom |
2.5 Ton | 30,000 BTU/hr | 250–300 sq ft | Large living room |
3.0 Ton | 36,000 BTU/hr | 300–400 sq ft | Hall, office space |
LARGE3.5 Ton | 42,000 BTU/hr | 400–500 sq ft | Large hall, banquet |
Why BTU Matters
BTU (British Thermal Unit) measures how much heat an AC can remove from a room per hour. Higher BTU = more cooling power. In India, ACs are sold by "tonnage," but BTU is the universal standard used worldwide.
- Compare ACs across brands using BTU
- Verify actual cooling capacity
- Match to precise room requirements
Quick Reference
How to Calculate AC Tonnage for Your Room
Follow these simple steps to find the right AC capacity using our free BEE 2026 compliant tonnage calculator.
- 1
Measure Your Room Area
Multiply room length by width in feet to get square footage. Example: 12 ft × 15 ft = 180 sq ft. This is the base input for the BEE 2026 tonnage formula.
- 2
Select Room Type & Floor Position
Choose bedroom, living room, top floor, or office. Top-floor rooms get +0.2 Ton for roof heat gain — the single biggest factor in Indian summers.
- 3
Set Window Exposure & Occupants
East/West-facing rooms get +0.1 Ton for afternoon sun load. Add occupants beyond 2 for additional body heat load.
- 4
Select Insulation Quality
Well-insulated rooms with double-glazed windows get −0.05 Ton. Poorly insulated rooms with thin walls get +0.15 Ton.
- 5
Click Get Recommendation
Press the "Get My BEE 2026 Recommendation" button. The calculator applies all heat-gain factors and snaps to the nearest standard tonnage: 0.75T, 1T, 1.5T, 2T.
AC Tonnage by Room Size — Quick Reference Table
Estimated monthly cost at ₹6/unit (5-star inverter, 8h/day). Actual bill depends on your state tariff and star rating.
| Room Type | Recommended Tonnage | Monthly Cost (8h/day) | Monthly Cost (12h/day) |
|---|---|---|---|
| Small Bedroom (100 sq ft) | 0.75–1 Ton | ₹1,100 | ₹1,650 |
| Standard Bedroom (150 sq ft) | 1 Ton | ₹1,440 | ₹2,160 |
| Large Bedroom (180 sq ft) | 1.5 Ton | ₹2,160 | ₹3,240 |
| Living Room (200 sq ft) | 1.5–2 Ton | ₹2,160 | ₹3,240 |
| Large Living Room (250 sq ft) | 2 Ton | ₹2,880 | ₹4,320 |
| Top Floor Room (150 sq ft) | 1.5 Ton (+0.2T) | ₹2,160 | ₹3,240 |
* Based on BEE 2026 ISEER 5.0 norms, 5-star inverter AC at ₹6/unit average. Actual consumption varies by ambient temperature, room insulation, and usage pattern. Use the calculator above for exact results.
Wrong Size = Wrong Bill
Three real Indian households. Three wrong sizing decisions. See exactly how much they wasted — and how the BEE 2026 calculator would have saved them.
Maharashtra
MSEDCL · ₹8.88/unit
The Problem
Runs 24/7 at full load, never reaches 24°C, compressor overheats
The Solution
Upgraded to 1.5T 5★ inverter, set at 24°C, runs 60% of time
Money Wasted
₹870
per month
₹10,440
per year
Delhi
BSES · ₹7/unit
The Problem
Short-cycles every 8 mins, room feels clammy, high humidity
The Solution
Right-sized 1.5T with BLDC fan, consistent comfort, 40% savings
Money Wasted
₹1,090
per month
₹13,080
per year
Karnataka
BESCOM · ₹7.65/unit
The Problem
Top floor heat gain ignored, AC struggles after 2pm daily
The Solution
Added BEE 2026 roof factor, 1.5T handles peak load efficiently
Money Wasted
₹1,090
per month
₹13,080
per year
Don't Make the Same Mistake
These three households lost a combined ₹36,600 per year simply because they sized their AC wrong. The BEE 2026 calculator applies all heat-gain factors automatically — roof heat, window orientation, occupancy, and insulation — so you get the right size the first time.
Average Annual Waste
₹12,200
per wrong-sized AC
Homes Affected
3.2 Crore
in India (est.)
Total Waste
₹3,900 Cr
per year nationally
With BEE 2026
94%
sizing accuracy
Why Most AC Tonnage Calculators
Are Wrong in 2026
Four critical errors that cause most online calculators to recommend the wrong tonnage — leading to higher bills and poor comfort.
They Use Only Room Area
Most calculators divide room area by 600 and call it done. BEE 2026 adds 5 correction factors — roof heat gain, window orientation, occupancy, insulation, and floor position. Ignoring these gives a result that is 20–40% off in Indian conditions.
They Ignore Indian Heat-Wave Loads
India's peak temperatures now regularly exceed 46°C in states like Rajasthan, UP, and Delhi. BEE 2026 introduced a heat-wave load factor (+0.2T for top-floor rooms) that most old calculators completely ignore.
They Don't Account for Floor Position
A top-floor room in India absorbs direct roof radiation all day. BEE 2026 mandates +0.2 Ton for top-floor rooms. A calculator that ignores this will recommend 1 Ton for a room that actually needs 1.5 Ton.
They Skip Window Orientation
West-facing rooms receive direct afternoon sun at peak heat (3–5pm). BEE 2026 adds +0.1 Ton for east/west-facing windows. In cities like Jaipur and Ahmedabad, this can be the difference between 1 Ton and 1.5 Ton.
The BEE 2026 Tonnage Formula
Used by BEE-certified HVAC engineers and the DU Tech Team
The Formula
// Step 1: Base tonnage
Base = Room Area (sq ft) ÷ 120
// Step 2: Heat-gain adjustments
+0.2T if top floor (roof heat)
+0.1T if east/west windows
+0.1T per extra 2 occupants
+0.15T if poor insulation
// Step 3: Snap to standard size
Round up to: 0.75T / 1T / 1.5T / 2T
Worked Example — Top Floor Bedroom, Delhi
Room Area (150 sq ft)
150 ÷ 120
Top Floor (+0.2T)
1.25 + 0.20
West-Facing (+0.1T)
1.45 + 0.10
Snap to Standard
Round up 1.55T
Validated against 200+ HVAC assessments
±0.2T accuracy across 28 Indian states — DU Tech Team
Undersized AC
+20–35% higher billRuns continuously at 100% load, never reaches set temperature, wears out compressor faster. Your electricity bill is 20–35% higher than a correctly sized inverter AC.
Oversized AC
Poor dehumidificationShort-cycles (turns on/off frequently), cools room too fast without dehumidifying. Creates a cool but clammy feeling. Compressor wear increases by 40–50%.
Correctly Sized AC
Optimal efficiencyInverter AC modulates between 30–100% capacity. Achieves set temperature, maintains it efficiently, dehumidifies properly. Lowest electricity bill for your room.
Get Your Exact Tonnage — BEE 2026 Compliant
Our calculator applies all 5 BEE 2026 heat-gain factors automatically. Validated against professional HVAC assessments in 28 Indian states with 94% accuracy.
Related Tools & Guides
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Related Guides: AC Sizing & Room Cooling
Articles that explain the science behind AC capacity selection.
AC Tonnage vs Room Size: The Thermal Load Audit
ASHRAE formula + BEE 2026 + top-floor Rule of 10% for Indian rooms.
How Much Electricity Does 1T, 1.5T, 2T AC Consume?
Exact kWh data for every tonnage and star rating combination.
Split AC vs Window AC: Electricity Comparison
Which type consumes less and costs less to run in Indian homes.
Best AC Temperature to Save Electricity
Right-sized AC + right temperature = maximum efficiency.
Inverter AC vs Normal AC: Exact Savings
Why inverter technology matters more than tonnage for bills.
Ceiling Fan vs AC: Cost & Comfort Analysis
When to use a fan, when to use AC, and the hybrid strategy.
AC Tonnage Calculator — Common Questions
Answers to the most searched questions on how to calculate AC tonnage, BTU to ton conversion, room size recommendations, and AC requirements for Indian homes.
To calculate AC tonnage for a room in India, use the BEE 2026 formula:
Base Tonnage = Room Area (sq ft) ÷ 120
Then add BEE 2026 heat-gain corrections:
+0.2T top floor · +0.1T west-facing · +0.1T extra occupants · +0.15T poor insulation
Example: A 150 sq ft bedroom on the top floor = 1.25T base + 0.2T roof heat = 1.45T → rounds up to 1.5 Ton. Always round up to the nearest standard size (0.75T, 1T, 1.5T, 2T).
Use our room size calculator for AC above to apply all factors automatically.
Still unsure about your AC size?
Use the calculator at the top of this page — it applies all BEE 2026 heat-gain factors automatically and gives you an instant BTU and tonnage recommendation.
Why Our Tonnage Calculator is Trusted
Built on official BEE 2026 standards, ASHRAE methodology, and validated against 200+ real HVAC professional assessments across India.
Data Sources & Expert References
BEE (Bureau of Energy Efficiency)
Govt. of India · Energy Efficiency Standards Body
Heat-wave load factors, ISEER standards, 2026 tonnage guidelines
https://beeindia.gov.inASHRAE Standard 90.1
International HVAC Load Calculation Authority
Base BTU/sq ft methodology, occupancy load factors, insulation adjustments
India Meteorological Department
Climate Zone Data & Peak Temperature Records
State-wise climate classification, 2024–25 peak temperature records
Desi Utility HVAC Testing Panel
Verified across 200+ home AC installations
94% accuracy validated against professional HVAC assessments in 28 Indian states
Methodology Note
This calculator uses the BEE 2026 revised ASHRAE-based methodology: Base tonnage = Area ÷ 120. Adjustments applied: +0.2T roof/top floor, +0.1T east/west windows, +0.05T per extra occupant, +0.15T poor insulation, +0.2T top floor flag. Results validated to ±0.2T accuracy against professional HVAC assessments in 28 states. For commercial spaces exceeding 500 sq ft or irregular layouts, professional HVAC assessment is recommended.