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

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

4 tons central AC or heat pump, about 43,900 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 Chickasha Experiment Station (1.9 mi away). Jul is the hottest month, averaging a high of 96.7°F and a low of 71°F, with about 94 days a year at 90°F or more. That gives a design temperature of 104°F against 75°F inside.

What it costs to run

About 3,317 kWh a year at SEER2 14.3, or roughly $458 at Oklahoma's average residential rate of 13.81¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Chickasha

Of the 43,900 BTU/hr, 20,880 comes through walls, roof and windows on a 104°F afternoon (48%), 13,000 is sun on the house (30%), 2,120 is four people and their appliances, and 7,900 is moisture the coil has to wring out of Chickasha's summer air (18%).

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 36,000 BTU/hr before the moisture allowance.

Other house sizes in Chickasha

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 Chickasha

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 1,080 hours a year at full output.

Chickasha against nearby cities

Of 45 Oklahoma cities here, Chickasha has the 16th highest cooling load. The range runs from Miami at 35,600 BTU/hr to Ardmore at 44,900.

Where Chickasha's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Chickasha Experiment Station, 1.9 miles from the center of Chickasha at 1,085 ft above sea level. That is close enough that the station's summers are Chickasha's summers.

No other city in this set uses Chickasha Experiment Station, so this sizing is Chickasha's alone.

The sun over Chickasha in late July

At 35.04°N, the noon sun on 21 July stands 75.4° above the horizon over Chickasha 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.

17,014 people live in Chickasha, the 32nd largest of the 45 Oklahoma cities sized on this site. Coordinates used: 35.0405, -97.9472.

Chickasha AC sizing questions