What size AC for Gainesville, TX? 4 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Gainesville needs

4 tons central AC or heat pump, about 44,000 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.7 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 4 tons for an average 2,000 sq ft house here, ask to see the Manual J load calculation behind it before you sign. That works out to one ton per 546 square feet in this climate. For a single room, size by the room: 22 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Gainesville 5 Ene (5.2 mi away). Aug is the hottest month, averaging a high of 94.3°F and a low of 72.3°F, with about 82 days a year at 90°F or more. That gives a design temperature of 101°F against 75°F inside.

What it costs to run

About 3,549 kWh a year at SEER2 14.3, or roughly $569 at Texas's average residential rate of 16.03¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Gainesville

Of the 44,000 BTU/hr, 18,720 comes through walls, roof and windows on a 101°F afternoon (43%), 13,000 is sun on the house (30%), 2,120 is four people and their appliances, and 10,200 is moisture the coil has to wring out of Gainesville's summer air (23%).

Heat through the shell is the biggest share here, so insulation and air sealing cut the size you need more than shading would. Sensible heat totals 33,840 BTU/hr before the moisture allowance.

Other house sizes in Gainesville

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,300 BTU/hr; a 350 sq ft living room needs about 7,700 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 13,200 BTU/hr.

Month by month in Gainesville

Aug alone uses 25% of the year's cooling energy. The unit runs the equivalent of 1,154 hours a year at full output.

Gainesville against nearby cities

Of 252 Texas cities here, Gainesville has the 191st highest cooling load. The range runs from Levelland at 37,300 BTU/hr to Laredo at 51,500.

Where Gainesville's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Gainesville 5 Ene, 5.2 miles from the center of Gainesville at 870 ft above sea level. That is close enough that the station's summers are Gainesville's summers.

No other city in this set uses Gainesville 5 Ene, so this sizing is Gainesville's alone.

The sun over Gainesville in late July

At 33.64°N, the noon sun on 21 July stands 76.8° above the horizon over Gainesville and the day runs 13 h 55 min from sunrise to sunset. A lower noon sun puts more of the day's heat on east and west walls than on the roof, which is why shading west glass pays off here. Shorter days give the house a longer night to shed the day's heat.

18,295 people live in Gainesville, the 164th largest of the 252 Texas cities sized on this site. Coordinates used: 33.6386, -97.1484.

Gainesville AC sizing questions