What size AC do you need?
Get a quick tonnage estimate for your New Braunfels home below, then see the square-footage rule it's based on — and why the right answer ultimately comes from a load calculation, not a rule of thumb.
Estimate the AC size your home needs
A quick rule-of-thumb starting point for New Braunfels homes. The real number comes from a load calculation — this tells you the ballpark to expect.
Industry rule of thumb — about 25 BTU per square foot, adjusted for your ceiling, sun, and occupants. A starting estimate, not an ANSI/ACCA Manual J load calculation, which a licensed pro runs using your insulation, windows, orientation, and local design temperature.
How this is estimated, and why a Manual J matters
We start at roughly 25 BTU per square foot, add 10% for high ceilings, adjust ±10% for sun or shade, and add 600 BTU for each person beyond two — then divide by 12,000 to get tons (1 ton = 12,000 BTU/hr). It lines up with the common "about 500 square feet per ton" rule.
This is deliberately a ballpark. A proper Manual J load calculation — the ANSI-recognized standard — accounts for your home's insulation, window area and orientation, air infiltration, and New Braunfels' design temperatures, which the square-footage rule can't see. Oversizing is a real risk: a system that's too big short-cycles, dehumidifies poorly, and wears out early, so the U.S. Department of Energy calls for a load calculation rather than guesswork.
How many tons of AC per square foot?
The common starting point is about one ton How much cooling a system delivers (1 ton ≈ 12,000 BTU/hour). Bigger home, more tons — but bigger is not always better. Full definition of cooling per 500–600 square feet, or roughly 25 BTU per square foot. This table shows where typical New Braunfels home sizes land before adjustments for ceilings, sun, and insulation.
| Home size | Approx. tonnage | Cooling capacity |
|---|---|---|
| 1,000 sq ft | 2 tons | 24,000–25,000 BTU/hr |
| 1,200 sq ft | 2.5 tons | 30,000 BTU/hr |
| 1,500 sq ft | 3 tons | 36,000–37,500 BTU/hr |
| 2,000 sq ft | 4 tons | 48,000–50,000 BTU/hr |
| 2,500 sq ft | 5 tons | 60,000–62,500 BTU/hr |
| 3,000 sq ft | 6 tons | 72,000–75,000 BTU/hr |
A rule-of-thumb starting point only — newer, well-insulated homes often need less, older or sun-exposed homes more. Tonnage is also the biggest single driver of install price, so once you have an estimate, see how it maps to replacement cost in New Braunfels.
Why a Manual J load calculation beats the rule of thumb
A Manual J load calculation The room-by-room math (industry standard: ACCA Manual J) that sizes your system correctly instead of guessing. Full definition — the ANSI/ACCA standard — sizes your system from the things square footage can't capture: insulation, window area and orientation, air leakage, and New Braunfels' design temperatures. A contractor who runs one (rather than just matching your old unit) is sizing it properly. Oversizing isn't a safe default — it short-cycles, dehumidifies poorly, and shortens equipment life.