What size AC for Fargo, ND? 2 tons for 2,000 sq ft

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

2 tons central AC or heat pump, about 24,900 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 69% 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 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 965 square feet in this climate. For a single room, size by the room: 12.4 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Fargo Hector International Airport (4.2 mi away). Jul is the hottest month, averaging a high of 82.1°F and a low of 59.4°F, with about 11 days a year at 90°F or more. That gives a design temperature of 86°F against 75°F inside.

What it costs to run

About 708 kWh a year at SEER2 14.3, or roughly $88 at North Dakota's average residential rate of 12.46¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Fargo

Of the 24,900 BTU/hr, 7,920 comes through walls, roof and windows on a 86°F afternoon (32%), 13,000 is sun on the house (52%), 2,120 is four people and their appliances, and 1,800 is moisture the coil has to wring out of Fargo's summer air (7%).

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 23,040 BTU/hr before the moisture allowance.

Other house sizes in Fargo

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 1,900 BTU/hr; a 350 sq ft living room needs about 4,300 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,400 BTU/hr.

Month by month in Fargo

Jul alone uses 36% of the year's cooling energy. The unit runs the equivalent of 407 hours a year at full output.

Fargo against nearby cities

Of 9 North Dakota cities here, Fargo has the 6th highest cooling load. The range runs from Grand Forks at 23,200 BTU/hr to Minot at 26,400.

Where Fargo's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Fargo Hector International Airport, 4.2 miles from the center of Fargo at 895 ft above sea level. That is close enough that the station's summers are Fargo's summers.

2 other cities use the same station and get the same climate inputs. The closest to Fargo: West Fargo (4 mi away, 6.4 mi from the station), Moorhead (4 mi away, 5.2 mi from the station). Fargo sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Fargo in late July

At 46.86°N, the noon sun on 21 July stands 63.5° above the horizon over Fargo and the day runs 15 h 07 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.

136,285 people live in Fargo, the largest of the 9 North Dakota cities sized on this site. Coordinates used: 46.8647, -96.8291.

Fargo AC sizing questions