What size AC & furnace for 3,000 sq ft?

Short answer

A 3,000 sq ft space needs roughly 60,000 BTU (5 tons) of cooling and about a 126,000 BTU furnace in a temperate, average-insulation home. Size up for hot climates, poor insulation, high ceilings, or lots of sun.

Cooling needed

60,000 BTU

Tonnage

5 ton

Furnace (heating)

126,000 BTU

Unit type

Central AC / ducted system

Cooling and heating 3,000 sq ft

For cooling, 3,000 sq ft at roughly 20 BTU per square foot works out to about 60,000 BTU (5 ton) in a temperate, average-insulation home. For heating, a furnace is sized by climate zone — around 126,000 BTU in a temperate climate, and more in a cold one (50–60 BTU/sq-ft up north).

These are whole-space estimates. Poor insulation, high ceilings, lots of glass, or an extreme climate all raise both numbers — run your home through the calculator to adjust them.

Size your exact home

Size 3,000 sq ft

Recommended central ac / ducted

Real, widely available units in the 36,000 BTU (3 tons) and up class. Independent picks — we're not affiliated with any manufacturer or retailer and earn nothing from these links. Always match the unit's BTU to the size above.

Best overall

Carrier · Trane · Lennox

2–5 ton condensers

Central AC · pro install · Premium efficiency & dealer networks

The premium tier for whole-home central AC — highest efficiency options and the largest professional dealer/service networks. Priced and installed per quote.

Get quotes from local dealers

Best value

Goodman

2–5 ton condensers

Central AC · pro install · Value-leader central condensers

The value leader in central AC — solid, widely serviced equipment at a lower installed cost than the premium brands.

Get quotes from local dealers

At this capacity you want a ducted central system — it must be sized with a Manual J load calculation and installed by a licensed HVAC contractor. There is no DIY buy-and-plug option, so get quotes from local dealers rather than buying online.

All home sizes BTU by room size

Frequently asked questions

How many BTU to cool 3,000 sq ft?

About 60,000 BTU (5 tons) of cooling for 3,000 sq ft in a temperate, average-insulation home — more in a hot climate or with poor insulation.

What size furnace for a 3,000 sq ft home?

Roughly a 126,000 BTU furnace in a temperate climate. Cold climates need 50–60 BTU/sq-ft, so the same home can need a larger furnace further north.

How many tons of AC for 3,000 sq ft?

5 tons (60,000 BTU), since one ton equals 12,000 BTU. Confirm with a Manual J load calculation before a professional install.