BTU Calculator (2024)

BTU Calculator (1)

What Size Air Conditioner Do I Need?

Let’s be honest, size matters. Especially when choosing the correct BTU size for an air conditioner you need installed in your new home or office. Choose too small a unit, you could end up with a room that’s not cool enough, or with an air conditioning unit that overheats soon enough. On the other hand, too large a unit for the space will not remove the necessary moisture from the room, making it feel clammy and uncomfortable. Here’s how to calculate BTU to find the perfect AC unit for your needs.

What is a BTU?

A BTU or British Thermal Unit is a measurement of how much energy is required to raise the temperature of one pound of water by one degree. That might not sound useful when it comes to aircons in your home or business but the underlying calculation is very important to staying comfortable.

Each ac unit or heater is rated to produce a certain number of BTUs.There are many factors that go into calculating BTUs, so we have put together a set of tools to help with air conditioner sizing.

Air Conditioner BTU Calculator Chart

The chart below is a great starting point for sizing your AC. These BTU calculator is based on a standard room with 8-foot ceilings, two windows and one door. If the room has more windows, doors or higher ceilings, adjust the BTUs upward.

Other factors in determining the BTU calculator result, would be the room’s purpose. Kitchens normally have more heat thanks to stoves and ovens, and rooms with computers and other electronics give off extra heat. Therefore, these rooms would require bumping the air conditioner size up.

What else should I look for when buying a room air conditioner?

Remember that bigger is not always better! Buying an air conditioner that is too large does not provide better cooling. An oversized air conditioner is actually less effective — and wastes energy at the same time. Make sure your unit is properly sized by using the BTU Calculator provided.

Properly Sized Room Air Conditioners

Room air conditioner sizing is all about matching the room size to the air conditioner size. A unit that is too big will be less effective and offer reduced air conditioner efficiency. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room, before it has a chance to remove the humidity.

The result will be a room that’s not very comfortable to spend time in That cool moist air will make the room feel damp and clammy. The most energy efficient air conditioner is sized to the square footage of the space to be cooled. Getting the right size means getting the comfort and the energy efficiency right.

BTU Calculator (2024)

FAQs

How do I figure out how many BTUs I need? ›

(desired temperature change) x (cubic feet of space) x . 133 = BTUs needed per hour.

How do you calculate BTU for a room? ›

Room Heat Calculator
  1. Take the measurements of your room in feet or metres. The multiply the Length of the room x the Width of the room x the Height of the room.
  2. The multiply this figure by a factor of 6 for BTU's or by 0.0606 for kW.
  3. The result is now the mimimum heat output required to heat this room.
Aug 31, 2018

How many BTU do I need for a 20x20 room? ›

To determine how many BTU you need to cool a 20 x 20 room, multiply the room's length by the width, then calculate 20 BTU for every square foot. Four hundred square feet x 20 = 8,000 BTU.

How many BTU per square foot calculator? ›

Size and Ceiling Height
Area To Be Cooled (square feet)Capacity Needed (BTUs per hour)
400 to 45010,000
450 to 55012,000
550 to 70014,000
700 to 1,00018,000
10 more rows

How many BTU do I need to heat 1500 square feet? ›

1,500-square-foot home would take between 45,000 and 90,000 BTUs. 1,800-square-foot home would take between 55,000 and 110,000 BTUs. 2,100-square-foot home would take between 65,000 and 125,000 BTUs. 2,400-square-foot homes would take between 75,000 and 145,000 BTUs.

How many BTUs for 2000 sq ft? ›

2000 square feet. X .40 heating factor (from the chart above) 80,000 Btu actual output.

How many BTUs for 500 sq ft? ›

Window Air Conditioning Chart
100 Sq. Ft.5,000 BTU
300 Sq. Ft.9,000 BTU
400 Sq. Ft.10,500 BTU
500 Sq. Ft.11,500 BTU
800 Sq. Ft.17,000 BTU
2 more rows
Oct 12, 2022

Is 5000 BTU enough for a bedroom? ›

Ideally, the room you place it in should be around 150 to 200 square feet. You'll therefore most benefit from a 5,000 BTU air conditioner in a room that is 10×10, 12×12, or 14×14 feet in size. Thus, it's generally suited for a single living room or bedroom.

How big of a room will 12000 BTU heat? ›

12,000 BTU – ~550 sq. ft to ~800 sq. ft. 15,000 BTU – ~750 sq.

Is $12,000 BTU enough for a bedroom? ›

As a guide, consider 5,000-BTU models for rooms 150 square feet or smaller, 8,000 BTUs for medium-size rooms (340 square feet), and 12,000 to 14,000-BTU models for rooms with square footage from 550 to 800. Having the correct power is imperative.

How many BTUs for 400 sq ft? ›

APPROXIMATE BTU OUTPUT NEEDED BY SQUARE FOOTAGE
APPROX. SQ.FT.RECOMMENDED INSULATION
Up to 40018,000 BTU
Up to 60027,000 BTU
Up to 80036,000 BTU
Up to 100045,000 BTU
17 more rows

What size room will 18,000 BTU cool? ›

550 to 1,000 square feet

How many BTUs for a 30x30 garage? ›

operate at 20 BTUs to 30 BTUs per square footage. However, these being ballpark estimates, you should confirm accurate cubic feet of cold air in your region and multiply that by the desired warmth in temperature.

What is the rule of thumb for BTU per square foot? ›

The DOE generally recommends 20 BTUs per square foot of living space. That is based on size alone. Therefore, a simple formula for calculating BTUs is to multiply the total square footage of your home by 20. But you may need more BTUs per sq.

Is 12000 BTU enough for 400 sq ft? ›

350 – 400 sq. feet: 9,000 BTUs. 400 – 450 sq. feet: 10,000 BTUs. 450 – 550 sq. feet: 12,000 BTUs. 550 – 700 sq. feet: 14,000 BTUs.

How many BTU do I need to heat a 12x12 room? ›

A 6,000 BTU mini split system will be able to handle a 12 x 12 room. Once you go over a 260 square foot room, you're going to need to go up to a 9,000 BTU mini split system. A 6,000 BTU mini split can usually handle up to 6,500 BTUs.

How many square feet will 12,000 BTU heat? ›

12,000 BTU – ~550 sq. ft to ~800 sq. ft. 15,000 BTU – ~750 sq.

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