AC Unit Lewisville, Texas

How Do I Know If My A/C Unit Is Big Enough?


Choosing the right sized air conditioner is crucial to achieving optimal temperatures, humidity levels and energy consumption. It is less expensive to purchase one unit that provides the right amount of cooling rather than multiple smaller units or one excessively large air conditioner. Fortunately, most people find it fairly easy to perform the necessary measurements and determine the appropriate size.

Steps To Choose The Right Size AC:

1. If you plan to cool a single room or part of a building, measure the desired area’s width and length with a measuring tape. Some rooms have complex shapes; you may need to split the area into multiple segments and measure them separately.

2. After writing down the measurements, use a calculator to discover how many square feet you need to cool. You will only have to multiply the width of the desired area by its length. Special formulas are necessary to determine the square footage of curved or triangular segments.

3. If you decide to install central A/C equipment, find the square footage of the entire building. This may prove difficult; try to find out if someone has already calculated it. Some homeowners obtain this information from county auditors, old real estate listings or documents about property taxes. Remember not to count the attic, basement or closets.

4. Use these guidelines to find the appropriate BTU/hour rating. You need approximately 6,000 BTUs to cool an area under 300 square feet, 10,000 BTUs for 301 to 549 sqft., 16,000 BTUs for 550 to 999 sqft., 22,000 BTUs for 1,000 to 1,199 sqft., 30,000 BTUs for 1,500 to 1,999 sqft. and 34,000 BTUs for 2000 to 2,499 square feet.

5. If necessary, adjust the BTU rating. Increase it by 4,000 if you need to cool a kitchen. Multiply the number by 1.1 if there is usually full sunlight or 0.9 if a building always stays in the shade. When there are normally three or more people in a room, compensate for body heat by adding 600 BTUs for every extra person.

The final step is to purchase a central or room air conditioner with the right BTU output rating.

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