What size AC for Susanville, CA? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 29,200 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 44% 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 2.5 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 822 square feet in this climate. For a single room, size by the room: 14.6 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Susanville 2sw (2.2 mi away). Jul is the hottest month, averaging a high of 88°F and a low of 53.1°F, with about 31 days a year at 90°F or more. That gives a design temperature of 93°F against 75°F inside.

What it costs to run

About 573 kWh a year at SEER2 14.3, or roughly $187 at California's average residential rate of 32.58¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Susanville

Of the 29,200 BTU/hr, 12,960 comes through walls, roof and windows on a 93°F afternoon (44%), 13,000 is sun on the house (45%), 2,120 is four people and their appliances, and 1,100 is moisture the coil has to wring out of Susanville's summer air (4%).

Sun is the biggest share here, more than heat through the walls, so shading west windows and a light roof cut the size you need more than extra insulation would. Sensible heat totals 28,080 BTU/hr before the moisture allowance.

Other house sizes in Susanville

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,200 BTU/hr; a 350 sq ft living room needs about 5,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,800 BTU/hr.

Month by month in Susanville

Jul alone uses 41% of the year's cooling energy. The unit runs the equivalent of 280 hours a year at full output.

Susanville against nearby cities

Of 376 California cities here, Susanville has the 196th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Susanville's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Susanville 2sw, 2.2 miles from the center of Susanville at 4,212 ft above sea level. That is close enough that the station's summers are Susanville's summers.

No other city in this set uses Susanville 2sw, so this sizing is Susanville's alone.

The sun over Susanville in late July

At 40.43°N, the noon sun on 21 July stands 70.0° above the horizon over Susanville and the day runs 14 h 28 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.

12,359 people live in Susanville, the 350th largest of the 376 California cities sized on this site. Coordinates used: 40.4337, -120.6283.

Susanville AC sizing questions