What size AC for West Memphis, AR? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 41,200 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.4 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 583 square feet in this climate. For a single room, size by the room: 20.6 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at W Memphis Municipal Airport (2.2 mi away). Jul is the hottest month, averaging a high of 91.4°F and a low of 72.2°F, with about 66 days a year at 90°F or more. That gives a design temperature of 98°F against 75°F inside.

What it costs to run

About 3,413 kWh a year at SEER2 14.3, or roughly $469 at Arkansas's average residential rate of 13.74¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in West Memphis

Of the 41,200 BTU/hr, 16,560 comes through walls, roof and windows on a 98°F afternoon (40%), 13,000 is sun on the house (32%), 2,120 is four people and their appliances, and 9,500 is moisture the coil has to wring out of West Memphis's summer air (23%).

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 31,680 BTU/hr before the moisture allowance.

Other house sizes in West Memphis

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,100 BTU/hr; a 350 sq ft living room needs about 7,200 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 12,400 BTU/hr.

Month by month in West Memphis

Jul alone uses 24% of the year's cooling energy. The unit runs the equivalent of 1,185 hours a year at full output.

West Memphis against nearby cities

Of 39 Arkansas cities here, West Memphis has the 8th highest cooling load. The range runs from Harrison at 33,100 BTU/hr to Fort Smith at 44,000.

Where West Memphis's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is W Memphis Municipal Airport, 2.2 miles from the center of West Memphis at 209 ft above sea level. That is close enough that the station's summers are West Memphis's summers.

1 other city uses the same station and get the same climate inputs. The closest to West Memphis: Marion (4 mi away, 4.7 mi from the station). West Memphis sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over West Memphis in late July

At 35.15°N, the noon sun on 21 July stands 75.3° above the horizon over West Memphis and the day runs 14 h 01 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.

23,538 people live in West Memphis, the 23rd largest of the 39 Arkansas cities sized on this site. Coordinates used: 35.1496, -90.1993.

West Memphis AC sizing questions