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How To Size A New AC

Whether your current AC has broken down or you’re moving into a new home, choosing the right size AC system is crucial. A unit that’s too large can drive up energy costs and reduce efficiency, while a unit that’s too small will struggle to cool your home, resulting in discomfort and higher bills. So how do you find the right size?

At Baldwin Cooling, Heating, Plumbing & Electrical, we’re here to guide you through each step. Here’s how to determine the ideal AC size for your home.


Step 1: Choosing the Right Air Conditioning Type

Before calculating AC size, decide on the type of system that best fits your home’s needs. There are two main options:

  • Traditional Central AC: Ideal for homes with existing ductwork. Central air systems offer powerful, whole-home cooling.
  • Ductless AC (Mini-Split): A great option for homes without ductwork or for those needing targeted cooling in specific rooms. Ductless units are compact, efficient, and easy to install.

Once you’ve chosen the system type, you can begin calculating the correct size.


Step 2: Calculating the Right AC Size

Sizing for a Ductless System

  1. Measure the length and width of the room you want to cool.
  2. Multiply the length by the width to find the square footage.
  3. Multiply the square footage by 25 BTUs to get the minimum BTU requirement.

For example, if your room is 10 feet by 15 feet (150 square feet), you’ll need a unit that provides at least 3,750 BTUs (150 x 25). Ductless systems are labeled by BTU capacity, making it easy to find the right unit.

Sizing for a Traditional Central System

Central air conditioners are measured in tons, where one ton equals 12,000 BTUs. The following formula can help you determine the tonnage needed:

(House square footage x 25 BTUs) / 12,000−0.5=AC size in tons\text{(House square footage x 25 BTUs) / 12,000} – 0.5 = \text{AC size in tons}

For example, a 2,000-square-foot home would need an AC unit around 3.5 tons.


Step 3: Consider Additional Factors

While square footage is essential, other factors can affect the size AC unit you need:

  • Number of Windows: More windows can increase heat gain, impacting cooling needs.
  • Insulation: Proper insulation reduces cooling load by retaining cool air.
  • Climate Zone: Warmer climates may require higher BTU output.
  • Ceiling Height: Taller ceilings mean more space to cool.
  • Ductwork: Poorly sealed ducts can reduce cooling efficiency.

A professional technician can help evaluate these factors to ensure you choose the perfect system size.


Reliable AC Replacement in Daphne

Sizing and installing an AC unit can be complicated, but Baldwin Cooling, Heating, Plumbing & Electrical makes it easy. For over 65 years, we’ve provided expert HVAC services to the Daphne area, ensuring each home stays cool and comfortable.

If you’re ready for a new AC or have questions about sizing, contact us today, and our team will handle everything from measurements to installation. We’re here to keep Daphne cool, one perfectly sized unit at a time.

Why Choose Us?

We stand by our 100% customer satisfaction guarantee

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What Our Customers Are Saying

Couldn’t Ask for Better Folks!

Ryan, Jacob and Sam the electrician were very knowledgeable, hard working and professional. They installed our Generac and were very polite and efficient. Couldn’t ask for better folks!

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Great job on installing new AC! The guys were very polite and professional. The work was completed in one day. We are very pleased with the work completed and competitive pricing!

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Excellent install of a generator by Jake & Ryan. They went over and above, working late waiting for the utility inspector to come out for final inspection. Couldn’t be happier…these guys are the best.

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