AC Sizing Guide — What Size AC Do I Need? | LC Heating & Air

What Do Tons and BTU Mean?

1 ton = 12,000 BTU/hour of cooling capacity. Common residential sizes:

1.5 tons (18,000 BTU): Small apartments, 600–900 sq ft
2 tons (24,000 BTU): Small homes, 900–1,200 sq ft
3 tons (36,000 BTU): Average homes, 1,200–1,800 sq ft
4 tons (48,000 BTU): Larger homes, 1,800–2,400 sq ft
5 tons (60,000 BTU): Large homes, 2,400–3,000 sq ft

Why Oversizing Is Worse Than Undersizing

Many contractors install oversized equipment to avoid callbacks. This is a mistake:

Short-cycling: An oversized AC cools the air quickly but shuts off before removing humidity, leaving you cold and clammy.
Higher energy bills: Starting and stopping uses more electricity than running steadily.
Shorter lifespan: Frequent cycling wears out the compressor faster.
Uneven temperatures: Some rooms get cold while others stay warm.

A properly sized system runs in longer, steadier cycles — cooling more evenly and efficiently.

LA-Specific Sizing Factors

Los Angeles Climate Zone 9 considerations:

Dry heat: Lower humidity means less latent cooling load — you may need slightly less tonnage than humid climates like Houston or Miami.
Sun exposure: West-facing walls and large windows can add 10–20% to your cooling load.
Older homes: Pre-1970 LA homes often have minimal insulation, increasing the load by 15–30%.
Ductwork: Leaky ducts in a hot attic can waste 20–40% of cooling capacity.

AC Size Guide for Los Angeles

Home Size	Tons	BTU/h	Typical Models
600–1,000 sq ft	1.5–2	18K–24K	Mini split or small split
1,000–1,500 sq ft	2.5–3	30K–36K	GSXS6S3010 / DCA16S30
1,500–2,000 sq ft	3–3.5	36K–42K	GSXS6S3610 / DCA16S36
2,000–2,500 sq ft	3.5–4	42K–48K	GSXS6S4810 / DCA16S48
2,500–3,000 sq ft	4–5	48K–60K	GSXS6S6010 / DCA16S60

Frequently Asked Questions

What size AC do I need for 2000 sq ft?

A 2,000 sq ft home in Los Angeles typically needs a 3.5–4 ton (42,000–48,000 BTU) air conditioner. Get a Manual J calculation for an exact answer based on your home's specific characteristics.

What happens if my AC is too big?

An oversized AC short-cycles — turning on and off frequently. This wastes energy, wears out the compressor, creates uneven temperatures, and fails to properly dehumidify your home.

What is a Manual J calculation?

Manual J is the industry-standard method for calculating heating and cooling loads. It factors in square footage, insulation, windows, orientation, climate zone, and occupancy to determine the exact tonnage your home needs.