How to calculate BTU per square foot

Calculate cooling capacity: which air conditioning system is suitable for which room size?

How many watts or BTU / h? We explain to you what cooling capacity your air conditioning system must provide so that you can buy the right cooling device straight away.

  1. What does BTU mean for an air conditioning system?
  2. What cooling capacity does an air conditioning system need?
  3. People and computers affect the cooling performance
  4. Calculate cooling capacity in watts and BTU
  5. Five tips for cooler rooms

Not only since the last heat in the Sahara did you know that you need a mobile air conditioning system. But what cooling capacity should it provide in order to cool down your apartment or individual rooms? With air conditioning you will usually find two pieces of information: wattage and BTU value. We break down these terms for you.

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What does BTU mean for an air conditioning system?

BTU is the abbreviation for British Thermal Unit. It describes the thermal energy it takes to heat a pound of water by one degree Fahrenheit. The cooling capacity of air conditioning systems is given in full in BTU / h. 1,000 BTU / h corresponds to 293.71 watts. So you can deduce the BTU value - and vice versa - from the wattage.

What cooling capacity does an air conditioning system need?

In order to calculate the cooling capacity for a room, you should know how big it is. Performs the following calculation:

Room area in square meters times 60 (good insulation, little sun) to 100 (little insulated, lots of sun).

This gives you the cooling capacity in watts that your air conditioning system should have.

People and computers affect the cooling performance

Good to know: If there are people in the room that you want to cool, the air conditioning system needs a higher cooling capacity. Adds 200 watts per person. Televisions, computers and other electrical devices also mean that the air conditioning system has to work harder. Here, the information on the individual heat sources gives you information about how you calculate them. The climate calculator from helps you to determine the correct wattage.

Calculate cooling capacity in watts and BTU

An example: You live in a well-insulated apartment with high levels of sunlight and need air conditioning for your living room. This has a room area of ​​25 square meters.

So you calculate: 25 x 80 - your mobile air conditioner should have 2,000 watts.

If you want to convert the value into BTU / h, proceed as follows:

Divide 2,000 by 293.71, then multiply it by 1,000. So you need a cooling capacity of around 6,800 BTU / h.

Five tips for cooler rooms

  1. Did you know that proper ventilation can save you air conditioning? Provides a real draft in the apartment in the late evening or early morning hours.
  2. Darken your house or apartment during the day. Shutters, blinds or special curtains keep the sun's rays and thus the heat outside.
  3. Avoid thick carpets in the warm season. They can really store heat - which makes them cozy home accessories on cold days.
  4. Turns devices off completely. The stand-by mode not only consumes electricity, it also ensures that heat is generated.
  5. Use light colors, preferably white or soft beige and gray tones. In this way, the heat is less stored, especially in sunny rooms.

You can find more tips here: