What size AC for Los Banos, CA? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 36,700 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.1 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 3.5 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 654 square feet in this climate. For a single room, size by the room: 18.3 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Merced 23 Wsw (12.3 mi away). Jul is the hottest month, averaging a high of 95.6°F and a low of 53.8°F, with about 98 days a year at 90°F or more. That gives a design temperature of 103°F against 75°F inside.

What it costs to run

About 1,231 kWh a year at SEER2 14.3, or roughly $401 at California's average residential rate of 32.58¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Los Banos

Of the 36,700 BTU/hr, 20,160 comes through walls, roof and windows on a 103°F afternoon (55%), 13,000 is sun on the house (35%), 2,120 is four people and their appliances, and 1,400 is moisture the coil has to wring out of Los Banos's summer air (4%).

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 35,280 BTU/hr before the moisture allowance.

Other house sizes in Los Banos

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,700 BTU/hr; a 350 sq ft living room needs about 6,400 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,000 BTU/hr.

Month by month in Los Banos

Jul alone uses 31% of the year's cooling energy. The unit runs the equivalent of 480 hours a year at full output.

Los Banos against nearby cities

Of 376 California cities here, Los Banos has the 124th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Los Banos's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Merced 23 Wsw, 12.3 miles from the center of Los Banos at 78 ft above sea level. That is close enough that the station's summers are Los Banos's summers.

1 other city uses the same station and get the same climate inputs. The closest to Los Banos: Newman (20 mi away, 9.4 mi from the station). Los Banos is farther from the station than 1 of them.

The sun over Los Banos in late July

At 37.06°N, the noon sun on 21 July stands 73.3° above the horizon over Los Banos and the day runs 14 h 11 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.

48,684 people live in Los Banos, the 185th largest of the 376 California cities sized on this site. Coordinates used: 37.0632, -120.8403.

Los Banos AC sizing questions