What size AC for Broken Arrow, OK? 4 tons for 2,000 sq ft

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

4 tons central AC or heat pump, about 44,000 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.7 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 4 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 546 square feet in this climate. For a single room, size by the room: 22 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Tulsa Richard L Jones Jr Airport (11.7 mi away). Jul is the hottest month, averaging a high of 94°F and a low of 72.5°F, with about 81 days a year at 90°F or more. That gives a design temperature of 101°F against 75°F inside.

What it costs to run

About 3,372 kWh a year at SEER2 14.3, or roughly $466 at Oklahoma's average residential rate of 13.81¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Broken Arrow

Of the 44,000 BTU/hr, 18,720 comes through walls, roof and windows on a 101°F afternoon (43%), 13,000 is sun on the house (30%), 2,120 is four people and their appliances, and 10,200 is moisture the coil has to wring out of Broken Arrow'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 33,840 BTU/hr before the moisture allowance.

Other house sizes in Broken Arrow

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,300 BTU/hr; a 350 sq ft living room needs about 7,700 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 13,200 BTU/hr.

Month by month in Broken Arrow

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 1,096 hours a year at full output.

Broken Arrow against nearby cities

Of 45 Oklahoma cities here, Broken Arrow has the 4th highest cooling load. The range runs from Miami at 35,600 BTU/hr to Ardmore at 44,900.

Where Broken Arrow's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Tulsa Richard L Jones Jr Airport, 11.7 miles from the center of Broken Arrow at 620 ft above sea level. That is close enough that the station's summers are Broken Arrow's summers.

6 other cities use the same station and get the same climate inputs. The closest to Broken Arrow: Coweta (8 mi away, 19.1 mi from the station), Bixby (8 mi away, 9.2 mi from the station), Jenks (11 mi away, 3.2 mi from the station), Glenpool (14 mi away, 6.5 mi from the station), Sapulpa (19 mi away, 7.9 mi from the station). Broken Arrow is farther from the station than 5 of them.

The sun over Broken Arrow in late July

At 36.04°N, the noon sun on 21 July stands 74.4° above the horizon over Broken Arrow and the day runs 14 h 06 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.

122,756 people live in Broken Arrow, the 4th largest of the 45 Oklahoma cities sized on this site. Coordinates used: 36.0365, -95.7810.

Broken Arrow AC sizing questions