What size AC for Payson, AZ? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 35,000 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 20% 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 3 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 686 square feet in this climate. For a single room, size by the room: 17.5 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Payson (1.7 mi away). Jul is the hottest month, averaging a high of 92.5°F and a low of 59.5°F, with about 65 days a year at 90°F or more. That gives a design temperature of 99°F against 75°F inside.

What it costs to run

About 1,310 kWh a year at SEER2 14.3, or roughly $201 at Arizona's average residential rate of 15.36¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Payson

Of the 35,000 BTU/hr, 17,280 comes through walls, roof and windows on a 99°F afternoon (49%), 13,000 is sun on the house (37%), 2,120 is four people and their appliances, and 2,600 is moisture the coil has to wring out of Payson's summer air (7%).

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 32,400 BTU/hr before the moisture allowance.

Other house sizes in Payson

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,600 BTU/hr; a 350 sq ft living room needs about 6,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,500 BTU/hr.

Month by month in Payson

Jul alone uses 34% of the year's cooling energy. The unit runs the equivalent of 535 hours a year at full output.

Payson against nearby cities

Of 44 Arizona cities here, Payson has the 39th highest cooling load. The range runs from Flagstaff at 24,000 BTU/hr to Bullhead City at 60,800.

Where Payson's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Payson, 1.7 miles from the center of Payson at 4,850 ft above sea level. That is close enough that the station's summers are Payson's summers.

No other city in this set uses Payson, so this sizing is Payson's alone.

The sun over Payson in late July

At 34.24°N, the noon sun on 21 July stands 76.2° above the horizon over Payson and the day runs 13 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. Shorter days give the house a longer night to shed the day's heat.

16,762 people live in Payson, the 36th largest of the 44 Arizona cities sized on this site. Coordinates used: 34.2438, -111.3190.

Payson AC sizing questions