What size AC for Coalinga, CA? 4 tons for 2,000 sq ft

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

4 tons central AC or heat pump, about 48,300 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 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 497 square feet in this climate. For a single room, size by the room: 24.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Coalinga (1.2 mi away). Jul is the hottest month, averaging a high of 100.8°F and a low of 68.8°F, with about 131 days a year at 90°F or more. That gives a design temperature of 109°F against 75°F inside.

What it costs to run

About 3,544 kWh a year at SEER2 14.3, or roughly $1,155 at California's average residential rate of 32.58¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Coalinga

Of the 48,300 BTU/hr, 24,480 comes through walls, roof and windows on a 109°F afternoon (51%), 13,000 is sun on the house (27%), 2,120 is four people and their appliances, and 8,700 is moisture the coil has to wring out of Coalinga'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 39,600 BTU/hr before the moisture allowance.

Other house sizes in Coalinga

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,600 BTU/hr; a 350 sq ft living room needs about 8,500 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 14,500 BTU/hr.

Month by month in Coalinga

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 1,049 hours a year at full output.

Coalinga against nearby cities

Of 376 California cities here, Coalinga has the 17th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Coalinga's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Coalinga, 1.2 miles from the center of Coalinga at 670 ft above sea level. That is close enough that the station's summers are Coalinga's summers.

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

The sun over Coalinga in late July

At 36.13°N, the noon sun on 21 July stands 74.3° above the horizon over Coalinga 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.

16,722 people live in Coalinga, the 318th largest of the 376 California cities sized on this site. Coordinates used: 36.1330, -120.3390.

Coalinga AC sizing questions