What Size Air Conditioner Do I Need?

Whether you’re building a new home or updating your existing heating and cooling system, there is one question you’re guaranteed to ponder: what size air conditioner do I need? Buying the ideal air conditioning size is a balancing act. Too large, and you could encounter poor humidity control and exorbitant energy expenses. Too small, and the unit might not be able to reach comfortable temperatures on scorching hot days. Proper air conditioner sizing is required to enjoy an efficient, cost-effective and comfortable cooling experience.

The Importance of Sizing Your Air Conditioner Correctly

Ensuring your air conditioner can generate the right cooling capacity is a matter of comfort and keeping your energy bills low. Here’s why you shouldn’t just guess the appropriate air conditioning system size:

  • Humidity control: An oversized unit cools too fast, preventing humidity removal and rendering your home clammy. A properly sized air conditioner will manage indoor humidity levels more efficiently.
  • Even temperatures: A properly sized air conditioner disseminates cool air evenly and minimizes unpleasant temperature fluctuations between cycles.
  • Peak day performance: An undersized system will struggle to get your home to the target temperature on hot summer afternoons, so you need a unit big enough to keep up with cooling demand.
  • Proper cycling: Air conditioners start up and turn back off with sufficient run time during each cycle. Units that are too large cycle too quickly, causing unnecessary wear and tear. On the other hand, an undersized system runs continually, which may cause it to get too hot.
  • Manageable utility bills: Cycling troubles caused by choosing the wrong size of air conditioner result in higher utility bills. However, a unit that is the recommended size will operate as designed and keep your utility bills in check.

Understanding Air Conditioner Size

Cooling capacity is calculated in British thermal units (BTUs). A BTU is a standard unit of energy that indicates the amount of heat an air conditioner can remove in one hour. A large percentage of room air conditioners range from 5,000 to 18,000 BTUs. Because central air conditioners are more powerful, they’re usually measured in tons. A one-ton system is comparable to 12,000 BTUs. Generally, central AC systems range from 1 to 5 tons.

Sizing a Room Air Conditioner

When examining window or portable air conditioners, sizing primarily depends on the room’s square footage. Measure the room—length x width—and match it to the appropriate BTUs:

  • A room measuring 150 to 350 square feet will probably require a 5,000 to 8,000 BTU air conditioner.
  • A room that is around 350 and 550 square feet could need an 8,000 to 12,000 BTU unit.
  • A large room or open area of 550 to 1,000 square feet may necessitate a 12,000 to 18,000 BTU unit.

These general recommendations don’t take into account factors like interior heat gain or how much sun streams in through the windows of the room. For a more exact calculation, seek expert advice from Service Experts Heating, Air Conditioning & Plumbing.

Sizing a Central Air Conditioner

Choosing the right size of central air conditioner begins with the home’s square footage, but accurate sizing demands a more in-depth look. HVAC professionals rely on load calculations explained in Manual J to determine a home’s specific cooling requirements. Here are the considerations that technicians will examine:

  • Square footage: How big your home is substantially affects its AC requirements, with more sizeable homes generally requiring more cooling capacity.
  • Local climate: Where you live impacts your cooling requirements as well. Parts of the country with sweltering hot, humid summers normally demand a higher cooling capacity than cooler, drier areas.
  • Interior heat gain: The heat produced inside your home is made by people, lights, electronics and appliances. More internal heat increases your home’s cooling needs.
  • Insulation levels: The amount of insulation in your walls, attic and floors affects how much heat gets into your home. Well-insulated homes keep cool air more efficiently, decreasing the cooling load.
  • Air infiltration rate: This describes how much outside air enters through leaks or cracks in the exterior of your home. Homes with a significant air infiltration requires more cooling to counter the warm, humid outdoor air that seeps through the walls and into your home.
  • Home orientation and window layout: The direction your home faces determines its sun exposure, which in turn can change the required cooling load. A single-family residence with sprawling south-facing windows absorbs more heat and requires a larger air conditioner than a north-facing condo.

Other Factors to Consider When Buying an AC

Besides knowing what size air conditioner you need, consider these additional factors when installing a new air conditioner:

  • Brand: Not all ACs are created equal. It’s vital to buy a trusted brand for reliability and longevity.
  • Efficiency rating: The seasonal energy efficiency ratio (SEER) shows the amount of heat an air conditioner can take out per unit of electricity it consumes. Higher SEER ratings signify greater efficiency, minimizing your utility bills.
  • Maintenance requirements: Regular maintenance keeps your system working correctly. Most air conditioner makers encourage yearly tune-ups to find and fix small problems before they turn into expensive repairs.

Get Expert Help Sizing Your Air Conditioner From Service Experts Heating, Air Conditioning & Plumbing

Choosing the best air conditioner size can be daunting. The Experts at Service Experts Heating, Air Conditioning & Plumbing are here to support you throughout the process. We provide custom cooling remedies to optimize home comfort, efficiency and energy savings.

From establishing your exact cooling needs to helping you browse different brands and efficiency ratings, we’re at your side at every step. For help selecting the perfect air conditioner for your home in the U.S., call 866-397-3787 today to schedule your appointment with Service Experts Heating, Air Conditioning & Plumbing.

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