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

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

4 tons central AC or heat pump, about 51,800 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 463 square feet in this climate. For a single room, size by the room: 25.9 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at China Lake Naf (4.3 mi away). Jul is the hottest month, averaging a high of 104.6°F and a low of 70.4°F, with about 141 days a year at 90°F or more. That gives a design temperature of 113°F against 75°F inside.

What it costs to run

About 3,862 kWh a year at SEER2 14.3, or roughly $1,258 at California's average residential rate of 32.58¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Ridgecrest

Of the 51,800 BTU/hr, 27,360 comes through walls, roof and windows on a 113°F afternoon (53%), 13,000 is sun on the house (25%), 2,120 is four people and their appliances, and 9,300 is moisture the coil has to wring out of Ridgecrest'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 42,480 BTU/hr before the moisture allowance.

Other house sizes in Ridgecrest

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,900 BTU/hr; a 350 sq ft living room needs about 9,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 15,500 BTU/hr.

Month by month in Ridgecrest

Jul alone uses 27% of the year's cooling energy. The unit runs the equivalent of 1,066 hours a year at full output.

Ridgecrest against nearby cities

Of 376 California cities here, Ridgecrest has the 16th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Ridgecrest's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is China Lake Naf, 4.3 miles from the center of Ridgecrest at 2,231 ft above sea level. That is close enough that the station's summers are Ridgecrest's summers.

No other city in this set uses China Lake Naf, so this sizing is Ridgecrest's alone.

The sun over Ridgecrest in late July

At 35.63°N, the noon sun on 21 July stands 74.8° above the horizon over Ridgecrest and the day runs 14 h 04 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.

28,373 people live in Ridgecrest, the 251st largest of the 376 California cities sized on this site. Coordinates used: 35.6285, -117.6640.

Ridgecrest AC sizing questions