What size AC for Elk River, MN? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 26,400 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 59% 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 908 square feet in this climate. For a single room, size by the room: 13.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Elk River (2.1 mi away). Jul is the hottest month, averaging a high of 83.4°F and a low of 60.9°F, with about 11 days a year at 90°F or more. That gives a design temperature of 88°F against 75°F inside.

What it costs to run

About 743 kWh a year at SEER2 14.3, or roughly $122 at Minnesota's average residential rate of 16.44¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Elk River

Of the 26,400 BTU/hr, 9,360 comes through walls, roof and windows on a 88°F afternoon (35%), 13,000 is sun on the house (49%), 2,120 is four people and their appliances, and 2,000 is moisture the coil has to wring out of Elk River'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 24,480 BTU/hr before the moisture allowance.

Other house sizes in Elk River

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,000 BTU/hr; a 350 sq ft living room needs about 4,600 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,900 BTU/hr.

Month by month in Elk River

Jul alone uses 40% of the year's cooling energy. The unit runs the equivalent of 402 hours a year at full output.

Elk River against nearby cities

Of 103 Minnesota cities here, Elk River has the 50th highest cooling load. The range runs from Hibbing at 20,200 BTU/hr to Winona at 29,000.

Where Elk River's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Elk River, 2.1 miles from the center of Elk River at 880 ft above sea level. That is close enough that the station's summers are Elk River's summers.

1 other city uses the same station and get the same climate inputs. The closest to Elk River: Otsego (5 mi away, 3.3 mi from the station). Elk River sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Elk River in late July

At 45.33°N, the noon sun on 21 July stands 65.1° above the horizon over Elk River and the day runs 14 h 57 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.

27,606 people live in Elk River, the 38th largest of the 103 Minnesota cities sized on this site. Coordinates used: 45.3322, -93.5665.

Elk River AC sizing questions