What size AC for Fernley, NV? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 40,600 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.4 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 592 square feet in this climate. For a single room, size by the room: 20.3 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Lahontan Dam (9.4 mi away). Jul is the hottest month, averaging a high of 96.4°F and a low of 65.6°F, with about 82 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 2,027 kWh a year at SEER2 14.3, or roughly $271 at Nevada's average residential rate of 13.36¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Fernley

Of the 40,600 BTU/hr, 20,160 comes through walls, roof and windows on a 103°F afternoon (50%), 13,000 is sun on the house (32%), 2,120 is four people and their appliances, and 5,300 is moisture the coil has to wring out of Fernley'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 35,280 BTU/hr before the moisture allowance.

Other house sizes in Fernley

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,000 BTU/hr; a 350 sq ft living room needs about 7,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 12,200 BTU/hr.

Month by month in Fernley

Jul alone uses 34% of the year's cooling energy. The unit runs the equivalent of 714 hours a year at full output.

Fernley against nearby cities

Of 10 Nevada cities here, Fernley has the 6th highest cooling load. The range runs from Carson at 30,700 BTU/hr to Henderson at 55,200.

Where Fernley's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Lahontan Dam, 9.4 miles from the center of Fernley at 4,167 ft above sea level. That is close enough that the station's summers are Fernley's summers.

No other city in this set uses Lahontan Dam, so this sizing is Fernley's alone.

The sun over Fernley in late July

At 39.56°N, the noon sun on 21 July stands 70.8° above the horizon over Fernley and the day runs 14 h 23 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.

25,508 people live in Fernley, the 7th largest of the 10 Nevada cities sized on this site. Coordinates used: 39.5648, -119.1894.

Fernley AC sizing questions