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      What size window air conditioner do I need?

      Enter your room. The answer uses the ENERGY STAR sizing guide and links straight to the most efficient units in that size.

      You need about 7,000 BTUSee 5,000-6,000 BTU models →
      Your room
      Recommended size
      7,000 BTU
      Buy this size class
      5,000-6,000 BTU

      Most efficient in that size: Midea MAW06S1KWT-A (16.0 CEER)

      ENERGY STAR guide: the table value for the floor area, 10% less for a heavily shaded room, 10% more for a very sunny one, 600 BTU per person beyond two and 4,000 BTU for a kitchen. Rooms over 2,500 sq ft need more than one unit or a central system.

      Window AC size chart

      Room sizeCapacityModels
      100-150 sq ft5,000 BTU5,000-6,000 BTU
      150-250 sq ft6,000 BTU5,000-6,000 BTU
      250-300 sq ft7,000 BTU5,000-6,000 BTU
      300-350 sq ft8,000 BTU8,000 BTU
      350-400 sq ft9,000 BTU10,000 BTU
      400-450 sq ft10,000 BTU10,000 BTU
      450-550 sq ft12,000 BTU12,000 BTU
      550-700 sq ft14,000 BTU14,000-15,000 BTU
      700-1,000 sq ft18,000 BTU18,000 BTU
      1,000-1,200 sq ft21,000 BTU24,000 BTU and up
      1,200-1,400 sq ft23,000 BTU24,000 BTU and up
      1,400-1,500 sq ft24,000 BTU24,000 BTU and up
      1,500-2,000 sq ft30,000 BTU24,000 BTU and up
      2,000-2,500 sq ft34,000 BTU24,000 BTU and up

      Source: ENERGY STAR room air conditioner sizing guide. Normal sun, two people.

      Common questions

      Questions7
      What size window air conditioner for 200 sq ft?
      About 6,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 5400 BTU if the room is heavily shaded and 6600 BTU if it is very sunny.
      What size window air conditioner for 300 sq ft?
      About 7,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 6300 BTU if the room is heavily shaded and 7700 BTU if it is very sunny.
      What size window air conditioner for 400 sq ft?
      About 9,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 8100 BTU if the room is heavily shaded and 9900 BTU if it is very sunny.
      What size window air conditioner for 500 sq ft?
      About 12,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 10800 BTU if the room is heavily shaded and 13200 BTU if it is very sunny.
      What size window air conditioner for 700 sq ft?
      About 14,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 12600 BTU if the room is heavily shaded and 15400 BTU if it is very sunny.
      What size window air conditioner for 1,000 sq ft?
      About 18,000 BTU with normal sun and two people, following the ENERGY STAR sizing guide. Use about 16200 BTU if the room is heavily shaded and 19800 BTU if it is very sunny.
      What happens if a window air conditioner is too big?
      It cools the air quickly and shuts off before it has removed much moisture, so the room feels cold and clammy, and frequent cycling wastes energy. Inverter units handle a slightly oversized room better, but the right size still works best.

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