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

What size AC a 2,000 sq ft house in Lumberton 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 Lumberton (1.8 mi away). Aug is the hottest month, averaging a high of 93.4°F and a low of 72.7°F, with about 109 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 4,276 kWh a year at SEER2 14.3, or roughly $686 at Texas's average residential rate of 16.03¢ per kWh. Cooling runs 8 months of the year here.

What drives the load in Lumberton

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 Lumberton'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 Lumberton

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 Lumberton

Aug alone uses 21% of the year's cooling energy. The unit runs the equivalent of 1,390 hours a year at full output.

Lumberton against nearby cities

Of 252 Texas cities here, Lumberton has the 196th highest cooling load. The range runs from Levelland at 37,300 BTU/hr to Laredo at 51,500.

Where Lumberton's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Lumberton, 1.8 miles from the center of Lumberton at 39 ft above sea level. That is close enough that the station's summers are Lumberton's summers.

No other city in this set uses Lumberton, so this sizing is Lumberton's alone.

The sun over Lumberton in late July

At 30.26°N, the noon sun on 21 July stands 80.1° above the horizon over Lumberton and the day runs 13 h 40 min from sunrise to sunset. With the sun that close to overhead, the roof takes most of the heat at midday and the west wall takes the rest after 3 pm. Shorter days give the house a longer night to shed the day's heat.

14,255 people live in Lumberton, the 201st largest of the 252 Texas cities sized on this site. Coordinates used: 30.2557, -94.2079.

Lumberton AC sizing questions