Sizing Guide
What Size Air Conditioner Do I Need?
As a rough starting point, homes in a hot climate need about one ton of cooling for every 500 to 600 square feet, so a 1,500 square foot home often lands near a 2.5 to 3 ton system. That is only an estimate. The accurate answer comes from a Manual J load calculation, which is the standard our team uses. Here is how sizing works and why it matters in East Texas. Call 903 HVAC at 903-393-1044.
Proper Manual J Sizing on Every Installation
Air conditioners are sized in tons, and one ton equals 12,000 BTUs of cooling per hour. A common rule of thumb in a hot climate is roughly one ton per 500 to 600 square feet of conditioned space. Use it to get in the ballpark, but never buy a system on square footage alone. In humid East Texas, the right size also depends on insulation, windows, sun exposure, and ductwork, which is why a load calculation beats any rule of thumb.
AC Size by Square Footage
The table below gives a rough estimate of the tonnage a home of each size might need in the East Texas climate. Texas heat shifts these numbers, so treat this as a starting point, not a final answer.
| Home Size (Conditioned Sq Ft) | Approximate AC Size (Tons) |
|---|---|
| 600 to 900 sq ft | ~1.5 ton |
| 900 to 1,200 sq ft | ~2 ton |
| 1,200 to 1,500 sq ft | ~2.5 ton |
| 1,500 to 1,800 sq ft | ~3 ton |
| 1,800 to 2,400 sq ft | ~4 ton |
| 2,400 to 3,000 sq ft | ~5 ton |
These figures are a rough estimate for East Texas homes. A two-story home, a house with lots of west-facing glass, or one with poor insulation can need more capacity than the table suggests, while a tightly sealed, well-insulated home may need less.
Why Manual J Beats a Rule of Thumb
A Manual J load calculation is the industry-standard method for sizing a system. Instead of guessing from square footage, it accounts for the factors that actually drive cooling demand in your home:
- Insulation levels in walls, ceilings, and floors.
- Windows and their number, size, direction, and glazing.
- Sun exposure and shade, which matter a lot under the East Texas sun.
- Ceiling height and home layout.
- Ductwork condition and how well air is distributed.
- Local design temperatures and humidity.
Getting the size right matters because both extremes cause problems. An undersized AC runs nonstop and still cannot keep up on the hottest afternoons. An oversized AC short-cycles, turning on and off too quickly to pull humidity out of the air, which leaves the house cool but clammy and wears the equipment faster. In a humid climate, that humidity control is a big part of comfort, so bigger is not better.
Get a Professional Load Calculation in Tyler
Before you replace a system, let our team run the numbers for your specific home rather than copying whatever size was there before, which may have been wrong to begin with. We perform proper sizing on every installation so your new system is matched to your home, not just its footprint. Learn more on our AC installation and replacement page, and when you are budgeting, see our guide on AC installation cost in Texas. If the space you are cooling is an addition, a shop, or a room without ductwork, the sizing works differently, and our guide on what size mini-split you need covers it room by room.
Want the Right Size the First Time?
Get a professional load calculation from a woman-owned, family-run East Texas team with over 40 years of experience.
903-393-1044 Book Your ServiceFrequently Asked Questions
As a rough rule of thumb in a hot climate, plan on about one ton of cooling for every 500 to 600 square feet of conditioned space. That is only a starting estimate. The accurate size comes from a Manual J load calculation that accounts for insulation, windows, sun exposure, and ductwork. We perform that calculation on every installation so your system is sized correctly.
A 2,000 square foot home in East Texas often needs roughly a 3.5 to 4 ton system based on the rule of thumb, but the real answer varies with insulation, window count, ceiling height, and sun exposure. A two-story or poorly insulated home may need more, while a tightly sealed home may need less. A Manual J load calculation gives the precise figure, and we run one before recommending a system.
