What size AC for South Sioux City, NE? 2.5 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in South Sioux City needs

2.5 tons central AC or heat pump, about 28,000 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 50% more than this climate needs. An oversized unit cools the air fast, shuts off before it pulls moisture out, and leaves the house cold and clammy.

If a contractor quotes you more than 2.5 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 857 square feet in this climate. For a single room, size by the room: 14 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Sioux City Airport (5.2 mi away). Jul is the hottest month, averaging a high of 85°F and a low of 63.4°F, with about 25 days a year at 90°F or more. That gives a design temperature of 90°F against 75°F inside.

What it costs to run

About 1,130 kWh a year at SEER2 14.3, or roughly $146 at Nebraska's average residential rate of 12.92¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in South Sioux City

Of the 28,000 BTU/hr, 10,800 comes through walls, roof and windows on a 90°F afternoon (39%), 13,000 is sun on the house (46%), 2,120 is four people and their appliances, and 2,100 is moisture the coil has to wring out of South Sioux City's summer air (8%).

Sun is the biggest share here, more than heat through the walls, so shading west windows and a light roof cut the size you need more than extra insulation would. Sensible heat totals 25,920 BTU/hr before the moisture allowance.

Other house sizes in South Sioux City

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,100 BTU/hr; a 350 sq ft living room needs about 4,900 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,400 BTU/hr.

Month by month in South Sioux City

Jul alone uses 33% of the year's cooling energy. The unit runs the equivalent of 577 hours a year at full output.

South Sioux City against nearby cities

Of 16 Nebraska cities here, South Sioux City has the lowest cooling load. The range runs from South Sioux City at 28,000 BTU/hr to Bellevue at 34,300.

Where South Sioux City's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Sioux City Airport, across the line in Iowa, 5.2 miles from the center of South Sioux City at 1,092 ft above sea level. That is close enough that the station's summers are South Sioux City's summers.

1 other city uses the same station and get the same climate inputs. The closest to South Sioux City: Sioux City (3 mi away, 7.2 mi from the station). South Sioux City sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over South Sioux City in late July

At 42.46°N, the noon sun on 21 July stands 67.9° above the horizon over South Sioux City and the day runs 14 h 39 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. Long days mean the house keeps gaining heat into the evening, well after the outdoor peak.

13,910 people live in South Sioux City, the 14th largest of the 16 Nebraska cities sized on this site. Coordinates used: 42.4621, -96.4130.

South Sioux City AC sizing questions