Air Conditioning Types

AC sizing is measured in tons (1 ton = 12,000 BTU/hr). Rough estimate: 1 ton per 400-600 sq ft, but this varies by climate, insulation, windows, and more. An undersized unit runs constantly; an oversized unit short-cycles and doesn't dehumidify well. Always get a professional Manual J load calculation for accurate sizing.

In 2026, the federal minimum is 14-15 SEER2 depending on region. For most homeowners, 16-18 SEER2 offers the best value. In hot climates with heavy AC use, 19+ SEER2 can pay for itself in energy savings. The highest ratings (22+) are for those prioritizing maximum efficiency or qualifying for utility rebates.

Central AC is better if you have existing ductwork and want whole-home cooling with invisible indoor units. Mini-splits are better for homes without ducts, room additions, or if you want zone control. Mini-splits are typically more efficient but cost more when cooling an entire home with multiple zones.

Central AC systems typically last 15-20 years, mini-splits 20 years, window units 10 years. Lifespan depends on quality, installation, maintenance, and usage. Well-maintained systems in moderate climates last longer. If your AC is 10-15 years old and needs major repairs, replacement is often more cost-effective.