What size AC for Detroit Lakes, MN? 2 tons for 2,000 sq ft

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

2 tons central AC or heat pump, about 21,700 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 93% 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 1,105 square feet in this climate. For a single room, size by the room: 10.9 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Detroit Lakes 1 Nne (2.1 mi away). Jul is the hottest month, averaging a high of 79.2°F and a low of 57.5°F, with about 7 days a year at 90°F or more. That gives a design temperature of 83°F against 75°F inside.

What it costs to run

About 448 kWh a year at SEER2 14.3, or roughly $74 at Minnesota's average residential rate of 16.44¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Detroit Lakes

Of the 21,700 BTU/hr, 5,760 comes through walls, roof and windows on a 83°F afternoon (27%), 13,000 is sun on the house (60%), 2,120 is four people and their appliances, and 800 is moisture the coil has to wring out of Detroit Lakes's summer air (4%).

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 20,880 BTU/hr before the moisture allowance.

Other house sizes in Detroit Lakes

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 1,600 BTU/hr; a 350 sq ft living room needs about 3,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 6,500 BTU/hr.

Month by month in Detroit Lakes

Jul alone uses 38% of the year's cooling energy. The unit runs the equivalent of 295 hours a year at full output.

Detroit Lakes against nearby cities

Of 103 Minnesota cities here, Detroit Lakes has the 99th highest cooling load. The range runs from Hibbing at 20,200 BTU/hr to Winona at 29,000.

Where Detroit Lakes's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Detroit Lakes 1 Nne, 2.1 miles from the center of Detroit Lakes at 1,355 ft above sea level. That is close enough that the station's summers are Detroit Lakes's summers.

No other city in this set uses Detroit Lakes 1 Nne, so this sizing is Detroit Lakes's alone.

The sun over Detroit Lakes in late July

At 46.81°N, the noon sun on 21 July stands 63.6° above the horizon over Detroit Lakes 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.

10,033 people live in Detroit Lakes, the 103rd largest of the 103 Minnesota cities sized on this site. Coordinates used: 46.8076, -95.8466.

Detroit Lakes AC sizing questions