What size AC for Maricopa, AZ? 5 tons for 2,000 sq ft

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

5 tons central AC or heat pump, about 59,000 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, which falls short here. On a design day the unit runs flat out and the house still drifts above 75°F by late afternoon.

If a contractor quotes you more than 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 407 square feet in this climate. For a single room, size by the room: 29.5 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Maricopa 4 N (5.3 mi away). Jul is the hottest month, averaging a high of 108.9°F and a low of 77.8°F, with about 183 days a year at 90°F or more. That gives a design temperature of 117°F against 75°F inside.

What it costs to run

About 6,199 kWh a year at SEER2 14.3, or roughly $952 at Arizona's average residential rate of 15.36¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Maricopa

Of the 59,000 BTU/hr, 30,240 comes through walls, roof and windows on a 117°F afternoon (51%), 13,000 is sun on the house (22%), 2,120 is four people and their appliances, and 13,600 is moisture the coil has to wring out of Maricopa'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 45,360 BTU/hr before the moisture allowance.

Other house sizes in Maricopa

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 4,400 BTU/hr; a 350 sq ft living room needs about 10,300 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 17,700 BTU/hr.

Month by month in Maricopa

Jul alone uses 22% of the year's cooling energy. The unit runs the equivalent of 1,503 hours a year at full output.

Maricopa against nearby cities

Of 44 Arizona cities here, Maricopa has the 2nd highest cooling load. The range runs from Flagstaff at 24,000 BTU/hr to Bullhead City at 60,800.

Where Maricopa's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Maricopa 4 N, 5.3 miles from the center of Maricopa at 1,160 ft above sea level. That is close enough that the station's summers are Maricopa's summers.

No other city in this set uses Maricopa 4 N, so this sizing is Maricopa's alone.

The sun over Maricopa in late July

At 33.04°N, the noon sun on 21 July stands 77.4° above the horizon over Maricopa and the day runs 13 h 52 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.

76,654 people live in Maricopa, the 17th largest of the 44 Arizona cities sized on this site. Coordinates used: 33.0419, -111.9993.

Maricopa AC sizing questions