What size AC for Carson, NV? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 30,700 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 37% 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 2.5 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 782 square feet in this climate. For a single room, size by the room: 15.4 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Carson City (2.2 mi away). Jul is the hottest month, averaging a high of 89.5°F and a low of 54.8°F, with about 40 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 676 kWh a year at SEER2 14.3, or roughly $90 at Nevada's average residential rate of 13.36¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Carson

Of the 30,700 BTU/hr, 14,400 comes through walls, roof and windows on a 95°F afternoon (47%), 13,000 is sun on the house (42%), 2,120 is four people and their appliances, and 1,200 is moisture the coil has to wring out of Carson'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 29,520 BTU/hr before the moisture allowance.

Other house sizes in Carson

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,300 BTU/hr; a 350 sq ft living room needs about 5,400 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 9,200 BTU/hr.

Month by month in Carson

Jul alone uses 42% of the year's cooling energy. The unit runs the equivalent of 315 hours a year at full output.

Carson against nearby cities

Of 10 Nevada cities here, Carson has the lowest cooling load. The range runs from Carson at 30,700 BTU/hr to Henderson at 55,200.

Where Carson's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Carson City, 2.2 miles from the center of Carson at 4,761 ft above sea level. That is close enough that the station's summers are Carson's summers.

No other city in this set uses Carson City, so this sizing is Carson's alone.

The sun over Carson in late July

At 39.15°N, the noon sun on 21 July stands 71.2° above the horizon over Carson 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.

58,148 people live in Carson, the 6th largest of the 10 Nevada cities sized on this site. Coordinates used: 39.1531, -119.7474.

Carson AC sizing questions