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

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

4 tons central AC or heat pump, about 45,700 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.8 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 525 square feet in this climate. For a single room, size by the room: 22.8 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Porterville (0.8 mi away). Jul is the hottest month, averaging a high of 98.4°F and a low of 68.4°F, with about 122 days a year at 90°F or more. That gives a design temperature of 106°F against 75°F inside.

What it costs to run

About 3,297 kWh a year at SEER2 14.3, or roughly $1,074 at California's average residential rate of 32.58¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Porterville

Of the 45,700 BTU/hr, 22,320 comes through walls, roof and windows on a 106°F afternoon (49%), 13,000 is sun on the house (28%), 2,120 is four people and their appliances, and 8,200 is moisture the coil has to wring out of Porterville'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 37,440 BTU/hr before the moisture allowance.

Other house sizes in Porterville

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,400 BTU/hr; a 350 sq ft living room needs about 8,000 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 13,700 BTU/hr.

Month by month in Porterville

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 1,032 hours a year at full output.

Porterville against nearby cities

Of 376 California cities here, Porterville has the 20th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Porterville's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Porterville, 0.8 miles from the center of Porterville at 393 ft above sea level. That is close enough that the station's summers are Porterville's summers.

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

The sun over Porterville in late July

At 36.06°N, the noon sun on 21 July stands 74.3° above the horizon over Porterville 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.

63,517 people live in Porterville, the 141st largest of the 376 California cities sized on this site. Coordinates used: 36.0635, -119.0336.

Porterville AC sizing questions