What size AC for Las Vegas, NM? 2 tons for 2,000 sq ft

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

2 tons central AC or heat pump, about 25,500 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 65% 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 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 943 square feet in this climate. For a single room, size by the room: 12.7 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Las Vegas Municipal Airport (5.6 mi away). Jul is the hottest month, averaging a high of 83.5°F and a low of 54.1°F, with about 13 days a year at 90°F or more. That gives a design temperature of 88°F against 75°F inside.

What it costs to run

About 399 kWh a year at SEER2 14.3, or roughly $61 at New Mexico's average residential rate of 15.34¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Las Vegas

Of the 25,500 BTU/hr, 9,360 comes through walls, roof and windows on a 88°F afternoon (37%), 13,000 is sun on the house (51%), 2,120 is four people and their appliances, and 1,000 is moisture the coil has to wring out of Las Vegas's summer air (4%).

Sun is the biggest share here, more than heat through the walls, so shading west windows and a light roof cut the size you need more than extra insulation would. Sensible heat totals 24,480 BTU/hr before the moisture allowance.

Other house sizes in Las Vegas

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 1,900 BTU/hr; a 350 sq ft living room needs about 4,400 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,600 BTU/hr.

Month by month in Las Vegas

Jul alone uses 40% of the year's cooling energy. The unit runs the equivalent of 224 hours a year at full output.

Las Vegas against nearby cities

Of 19 New Mexico cities here, Las Vegas has the lowest cooling load. The range runs from Las Vegas at 25,500 BTU/hr to Sunland Park at 44,800.

Where Las Vegas's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Las Vegas Municipal Airport, 5.6 miles from the center of Las Vegas at 6,870 ft above sea level. That is close enough that the station's summers are Las Vegas's summers.

No other city in this set uses Las Vegas Municipal Airport, so this sizing is Las Vegas's alone.

The sun over Las Vegas in late July

At 35.60°N, the noon sun on 21 July stands 74.8° above the horizon over Las Vegas and the day runs 14 h 04 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.

12,711 people live in Las Vegas, the 15th largest of the 19 New Mexico cities sized on this site. Coordinates used: 35.6048, -105.2170.

Las Vegas AC sizing questions