What size AC for Santa Clarita, CA? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 38,100 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.2 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 630 square feet in this climate. For a single room, size by the room: 19 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Van Nuys Airport (14.1 mi away). Aug is the hottest month, averaging a high of 93.1°F and a low of 64.9°F, with about 77 days a year at 90°F or more. That gives a design temperature of 100°F against 75°F inside.

What it costs to run

About 2,553 kWh a year at SEER2 14.3, or roughly $832 at California's average residential rate of 32.58¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Santa Clarita

Of the 38,100 BTU/hr, 18,000 comes through walls, roof and windows on a 100°F afternoon (47%), 13,000 is sun on the house (34%), 2,120 is four people and their appliances, and 5,000 is moisture the coil has to wring out of Santa Clarita's summer air (13%).

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 33,120 BTU/hr before the moisture allowance.

Other house sizes in Santa Clarita

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,900 BTU/hr; a 350 sq ft living room needs about 6,700 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,400 BTU/hr.

Month by month in Santa Clarita

Aug alone uses 24% of the year's cooling energy. The unit runs the equivalent of 958 hours a year at full output.

Santa Clarita against nearby cities

Of 376 California cities here, Santa Clarita has the 85th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Santa Clarita's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Van Nuys Airport, 14.1 miles from the center of Santa Clarita at 785 ft above sea level. That is close enough that the station's summers are Santa Clarita's summers.

4 other cities use the same station and get the same climate inputs. The closest to Santa Clarita: San Fernando (10 mi away, 6.2 mi from the station), Simi Valley (18 mi away, 15.2 mi from the station), Calabasas (22 mi away, 11.4 mi from the station), Agoura Hills (24 mi away, 16.2 mi from the station). Santa Clarita is farther from the station than 2 of them.

The sun over Santa Clarita in late July

At 34.42°N, the noon sun on 21 July stands 76.0° above the horizon over Santa Clarita and the day runs 13 h 58 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.

229,159 people live in Santa Clarita, the 16th largest of the 376 California cities sized on this site. Coordinates used: 34.4165, -118.5007.

Santa Clarita AC sizing questions