Room size → BTU, tonnage & unit type
Short answer
A 1,500 sq ft space needs roughly 30,000 BTU (2.5 tons) of cooling and about a 63,000 BTU furnace in a temperate, average-insulation home. Size up for hot climates, poor insulation, high ceilings, or lots of sun.
Cooling needed
30,000 BTU
Tonnage
2.5 ton
Furnace (heating)
63,000 BTU
Unit type
Central AC / ducted system
For cooling, 1,500 sq ft at roughly 20 BTU per square foot works out to about 30,000 BTU (2.5 ton) in a temperate, average-insulation home. For heating, a furnace is sized by climate zone — around 63,000 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.
Real, widely available units in the 24,000 – 36,000 BTU 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
2–5 zones · up to ~48k BTU
Multi-zone mini-split · DIY · Quick-connect · self-install warranty
Cool several rooms from one outdoor unit, each with its own thermostat, using the same DIY quick-connect line sets — the easiest multi-zone to self-install.
Find on AmazonBest value
2–4 zones
Multi-zone mini-split · Lower cost per zone
A cost-effective multi-head system when you want independent control of several rooms and don’t need DIY line sets.
Find on AmazonBudget pick
2–4 zones
Multi-zone mini-split · heat pump · Cools + heats every zone
Multi-zone heat-pump comfort at a value price, from the same line as our single-zone best-overall pick.
Find on AmazonOne outdoor condenser feeds two or more indoor heads — right when you’re cooling several rooms rather than one big space.
About 30,000 BTU (2.5 tons) of cooling for 1,500 sq ft in a temperate, average-insulation home — more in a hot climate or with poor insulation.
Roughly a 63,000 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.
2.5 tons (30,000 BTU), since one ton equals 12,000 BTU. Confirm with a Manual J load calculation before a professional install.