What size AC for Goldsboro, NC? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 37,800 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.1 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 3.5 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 635 square feet in this climate. For a single room, size by the room: 18.9 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Goldsboro 4 Se (2.4 mi away). Jul is the hottest month, averaging a high of 91°F and a low of 71.7°F, with about 61 days a year at 90°F or more. That gives a design temperature of 97°F against 75°F inside.

What it costs to run

About 3,070 kWh a year at SEER2 14.3, or roughly $459 at North Carolina's average residential rate of 14.94¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Goldsboro

Of the 37,800 BTU/hr, 15,840 comes through walls, roof and windows on a 97°F afternoon (42%), 13,000 is sun on the house (34%), 2,120 is four people and their appliances, and 6,800 is moisture the coil has to wring out of Goldsboro's summer air (18%).

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 30,960 BTU/hr before the moisture allowance.

Other house sizes in Goldsboro

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,800 BTU/hr; a 350 sq ft living room needs about 6,600 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,300 BTU/hr.

Month by month in Goldsboro

Jul alone uses 24% of the year's cooling energy. The unit runs the equivalent of 1,162 hours a year at full output.

Goldsboro against nearby cities

Of 91 North Carolina cities here, Goldsboro has the 20th highest cooling load. The range runs from Boone at 21,700 BTU/hr to Lumberton at 40,200.

Where Goldsboro's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Goldsboro 4 Se, 2.4 miles from the center of Goldsboro at 109 ft above sea level. That is close enough that the station's summers are Goldsboro's summers.

No other city in this set uses Goldsboro 4 Se, so this sizing is Goldsboro's alone.

The sun over Goldsboro in late July

At 35.38°N, the noon sun on 21 July stands 75.0° above the horizon over Goldsboro and the day runs 14 h 02 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.

34,629 people live in Goldsboro, the 31st largest of the 91 North Carolina cities sized on this site. Coordinates used: 35.3782, -77.9719.

Goldsboro AC sizing questions