What size AC for La Cañada Flintridge, CA? 3 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in La Cañada Flintridge needs

3 tons central AC or heat pump, about 33,900 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 24% 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 3 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 707 square feet in this climate. For a single room, size by the room: 17 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Burbank Glendale Pasadena Airport (9.5 mi away). Aug is the hottest month, averaging a high of 88.9°F and a low of 64.9°F, with about 54 days a year at 90°F or more. That gives a design temperature of 95°F against 75°F inside.

What it costs to run

About 2,058 kWh a year at SEER2 14.3, or roughly $670 at California's average residential rate of 32.58¢ per kWh. Cooling runs 6 months of the year here.

What drives the load in La Cañada Flintridge

Of the 33,900 BTU/hr, 14,400 comes through walls, roof and windows on a 95°F afternoon (42%), 13,000 is sun on the house (38%), 2,120 is four people and their appliances, and 4,400 is moisture the coil has to wring out of La Cañada Flintridge'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 29,520 BTU/hr before the moisture allowance.

Other house sizes in La Cañada Flintridge

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,600 BTU/hr; a 350 sq ft living room needs about 6,000 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,200 BTU/hr.

Month by month in La Cañada Flintridge

Aug alone uses 25% of the year's cooling energy. The unit runs the equivalent of 867 hours a year at full output.

La Cañada Flintridge against nearby cities

Of 376 California cities here, La Cañada Flintridge has the 147th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where La Cañada Flintridge's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Burbank Glendale Pasadena Airport, 9.5 miles from the center of La Cañada Flintridge at 731 ft above sea level. That is close enough that the station's summers are La Cañada Flintridge's summers.

2 other cities use the same station and get the same climate inputs. The closest to La Cañada Flintridge: Glendale (3 mi away, 7 mi from the station), Burbank (7 mi away, 2.3 mi from the station). La Cañada Flintridge is farther from the station than 2 of them.

The sun over La Cañada Flintridge in late July

At 34.21°N, the noon sun on 21 July stands 76.2° above the horizon over La Cañada Flintridge and the day runs 13 h 57 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.

19,621 people live in La Cañada Flintridge, the 300th largest of the 376 California cities sized on this site. Coordinates used: 34.2097, -118.2001.

La Cañada Flintridge AC sizing questions