What Size AC Do I Need? A Guide for Bay County Homeowners

One of the most common mistakes homeowners make when replacing their AC is choosing the wrong size. Many assume bigger is better, but an oversized AC can cause as many problems as an undersized one. Here's what Bay County homeowners need to know about AC sizing.

Why Size Matters

An AC that's too small will struggle to cool your home, run constantly, and drive up energy bills. But an AC that's too large will cool too quickly, shut off before removing humidity, and create a cold, clammy feeling. Proper sizing ensures efficient operation, comfort, and lower energy costs.

AC Size Is Measured in Tons

AC capacity is measured in "tons" — one ton equals 12,000 BTUs (British Thermal Units) of cooling capacity. Common sizes range from 1.5 tons (18,000 BTUs) for small homes to 5 tons (60,000 BTUs) for large homes.

The Rule of Thumb (Not Recommended)

A common rule of thumb suggests 1 ton per 400-600 square feet. So a 2,000-square-foot home might need 3-5 tons. However, this is just a starting point. Many factors affect the actual size needed, and this rule can be off by 50% or more.

What Affects AC Size Requirements?

• Square footage: Larger homes need more capacity
• Ceiling height: High ceilings increase volume to cool
• Windows: Number, size, and orientation affect heat gain
• Insulation: Well-insulated homes need less capacity
• Sun exposure: South and west-facing windows add heat
• Number of occupants: More people generate more heat
• Appliances: Heat-generating appliances increase load
• Climate: Panama City's heat and humidity require more capacity

Why Bigger Isn't Better

An oversized AC cools your home quickly, then shuts off. This creates several problems:

• Poor humidity control: The system doesn't run long enough to remove moisture
• Short cycling: Frequent on/off cycles increase wear and tear
• Higher energy costs: Startup consumes more energy than steady operation
• Uneven temperatures: Some rooms may feel cold while others are warm
• Reduced lifespan: Short cycling wears out components faster

The Professional Solution: Manual J Load Calculation

Professional HVAC contractors use Manual J load calculation software to determine the exact size needed. This process considers:

• Detailed measurements of your home
• Window types and orientations
• Insulation levels in walls, attic, and floors
• Local climate data
• Number of occupants and their habits
• Heat-generating appliances

A Manual J calculation takes 1-2 hours but ensures your new AC is perfectly sized for your home.

Common Sizing Mistakes

Avoid these common errors:

• Matching old system size: Your old system might have been wrong
• Using square footage alone: Ignores many important factors
• Oversizing "to be safe": Creates more problems than it solves
• Not considering home improvements: New windows or insulation change requirements

What About Zoned Systems?

For larger homes or multi-story buildings, a zoned system might be better than one large unit. Zoned systems use dampers to control airflow to different areas, allowing different temperatures in different zones. This can be more efficient and comfortable than a single oversized unit.

Get Professional Sizing

Don't guess at AC size — get it right the first time. At Perfected Air Solutions, we perform detailed Manual J load calculations for every AC installation. This ensures your new system is properly sized for efficiency, comfort, and longevity. Call us at (850) 628-7880 for a free consultation and sizing assessment.