What size AC for Elk Grove, CA? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 35,000 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 20% 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 686 square feet in this climate. For a single room, size by the room: 17.5 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Sacramento Airport Asos (8.8 mi away). Jul is the hottest month, averaging a high of 92.6°F and a low of 59.2°F, with about 76 days a year at 90°F or more. That gives a design temperature of 99°F against 75°F inside.

What it costs to run

About 1,685 kWh a year at SEER2 14.3, or roughly $549 at California's average residential rate of 32.58¢ per kWh. Cooling runs 6 months of the year here.

What drives the load in Elk Grove

Of the 35,000 BTU/hr, 17,280 comes through walls, roof and windows on a 99°F afternoon (49%), 13,000 is sun on the house (37%), 2,120 is four people and their appliances, and 2,600 is moisture the coil has to wring out of Elk Grove's summer air (7%).

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 32,400 BTU/hr before the moisture allowance.

Other house sizes in Elk Grove

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 6,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,500 BTU/hr.

Month by month in Elk Grove

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 689 hours a year at full output.

Elk Grove against nearby cities

Of 376 California cities here, Elk Grove has the 139th highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Elk Grove's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Sacramento Airport Asos, 8.8 miles from the center of Elk Grove at 19 ft above sea level. That is close enough that the station's summers are Elk Grove's summers.

2 other cities use the same station and get the same climate inputs. The closest to Elk Grove: Galt (11 mi away, 19.6 mi from the station), West Sacramento (13 mi away, 4.3 mi from the station). Elk Grove is farther from the station than 1 of them.

The sun over Elk Grove in late July

At 38.41°N, the noon sun on 21 July stands 72.0° above the horizon over Elk Grove and the day runs 14 h 17 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.

182,797 people live in Elk Grove, the 26th largest of the 376 California cities sized on this site. Coordinates used: 38.4146, -121.3850.

Elk Grove AC sizing questions