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AC SIZE · 1,700 SQ FT (158 M²)

What Size AC for 1,700 Sq Ft?

A 1,700 sq ft home in a warm climate needs about 43,700 BTU/h (3.6 tons), so a 3.5 ton AC. Allow 3 ton in a mild climate and 5 ton in a hot one. In very hot, lightly insulated homes in Pakistan or India, it is about 11 tons in total, or 8 split units of 1.5 ton.

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Space
ft²
ft
Conditions
Cooling load, thousand BTU/hCooling load, thousand BTU/hFloor area × climate42.5kAfter ceiling and sun42.5kPeople over two+1.2kTotal, 3.5 ton43.7kmyconstructioncalculator.com
Diagram updates as you type.

Results

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Recommended AC size
3.5ton
Cooling load43,700 BTU/h
Cooling load in kW12.81 kW
Exact tonnage3.64 tons
Area per ton466.8 ft² per ton
Or 1.5 ton units3 units

This is a rule-of-thumb size for choosing a unit. For a central system or a new house, ask for a room-by-room heat-gain calculation (ACCA Manual J or similar).

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Working
  1. Base load = 1,700 ft² × 25 BTU/h per ft² = 42,500 BTU/h
  2. Ceiling 8 ft or lower: no height adjustment
  3. Sun: × 1; people over two: + 1,200 BTU/h; kitchen: + 0 BTU/h
  4. Cooling load = 43,700 BTU/h ÷ 12,000 = 3.64 tons (12.81 kW)
  5. Size: smallest standard unit covering 95% of the load (3.46 t) = 3.5 ton
Results are estimates for planning and material ordering only. They are not a substitute for structural design or approval by a qualified engineer. Read the full disclaimer.
AC Size for 1,700 Sq Ft by Climate
ClimateCooling loadkWAC size
Mild (UK, northern Europe)35,200 BTU/h10.33 ton
Warm (most of the US)43,700 BTU/h12.83.5 ton
Hot (US South, tropics)52,200 BTU/h15.35 ton
Very hot (Pakistan, India, Gulf)137,200 BTU/h40.211 tons in total
For 4 people, an 8 ft ceiling and average sun. The size is the smallest standard unit that covers 95% of the load; above 5 tons the total is shared between several units.
What Changes the Size (Warm Climate)
SituationCooling loadAC size
4 people, 8 ft ceiling, average sun43,700 BTU/h3.5 ton
Heavily shaded (−10%)39,450 BTU/h3.5 ton
Very sunny or top floor (+10%)47,950 BTU/h4 ton
10 ft ceiling49,013 BTU/h4 ton
Includes the kitchen (+4,000 BTU/h)47,700 BTU/h4 ton
6 people44,900 BTU/h4 ton
How It Is Worked Out
  1. Base load = 1,700 sq ft × 25 BTU/h per sq ft (warm climate) = 42,500 BTU/h
  2. People over two: (4 − 2) × 600 = 1,200 BTU/h
  3. Cooling load = 43,700 BTU/h ÷ 12,000 = 3.64 tons (12.81 kW)
  4. 95% of 3.64 = 3.46 tons → 3.5 ton
Change any figure in the calculator above to match your home. The method is explained on the AC Tonnage Calculator page.
Other Floor Areas
Frequently Asked Questions
How many tons of AC do I need for 1,700 sq ft?
3.5 ton in a warm climate, for 4 people and an 8 ft ceiling. Allow 3 ton in a mild climate and 5 ton in a hot one. In a very hot climate with little insulation, it is about 11 tons in total, or 8 split units of 1.5 ton.
How many BTU do I need for 1,700 sq ft?
About 35,200 BTU/h in a mild climate, 43,700 in a warm one and 52,200 in a hot one. Very hot, lightly insulated homes need about 137,200 BTU/h.
Is a 3 ton AC enough for 1,700 sq ft?
In a mild climate, yes. In a warm climate it covers about 82% of the 43,700 BTU/h load, so it runs flat out on hot days and a 3.5 ton unit is the better fit.
How many 1.5 ton ACs for 1,700 sq ft in Pakistan or India?
About 8 split units of 1.5 ton, one or more per room, for 40 to 48°C summers and little insulation (about 1 ton per 150 sq ft). Size each room on its own with the calculator above.