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

What size AC a 2,000 sq ft house in Marysville 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: 19.1 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Marysville Airport (asos) (3.5 mi away). Jul is the hottest month, averaging a high of 96.2°F and a low of 60.7°F, with about 99 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 1,956 kWh a year at SEER2 14.3, or roughly $637 at California's average residential rate of 32.58¢ per kWh. Cooling runs 6 months of the year here.

What drives the load in Marysville

Of the 38,100 BTU/hr, 20,160 comes through walls, roof and windows on a 103°F afternoon (53%), 13,000 is sun on the house (34%), 2,120 is four people and their appliances, and 2,800 is moisture the coil has to wring out of Marysville'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 35,280 BTU/hr before the moisture allowance.

Other house sizes in Marysville

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 11,500 BTU/hr.

Month by month in Marysville

Jul alone uses 28% of the year's cooling energy. The unit runs the equivalent of 734 hours a year at full output.

Marysville against nearby cities

Of 376 California cities here, Marysville has the 92nd highest cooling load. The range runs from Corte Madera at 15,700 BTU/hr to Palm Desert at 59,000.

Where Marysville's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Marysville Airport (asos), 3.5 miles from the center of Marysville at 62 ft above sea level. That is close enough that the station's summers are Marysville's summers.

1 other city uses the same station and get the same climate inputs. The closest to Marysville: Yuba City (3 mi away, 4.3 mi from the station). Marysville sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Marysville in late July

At 39.15°N, the noon sun on 21 July stands 71.2° above the horizon over Marysville and the day runs 14 h 21 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.

12,714 people live in Marysville, the 344th largest of the 376 California cities sized on this site. Coordinates used: 39.1515, -121.5834.

Marysville AC sizing questions