What size AC for Jackson, WY? 2 tons for 2,000 sq ft

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

2 tons central AC or heat pump, about 21,700 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 93% 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 1,105 square feet in this climate. For a single room, size by the room: 10.9 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Moose 1 Nne (13.5 mi away). Jul is the hottest month, averaging a high of 79.2°F and a low of 42.8°F, with about 1 day a year at 90°F or more. That gives a design temperature of 83°F against 75°F inside.

What it costs to run

About 20 kWh a year at SEER2 14.3, or roughly $3 at Wyoming's average residential rate of 14.01¢ per kWh. Cooling runs 0 months of the year here.

What drives the load in Jackson

Of the 21,700 BTU/hr, 5,760 comes through walls, roof and windows on a 83°F afternoon (27%), 13,000 is sun on the house (60%), 2,120 is four people and their appliances, and 800 is moisture the coil has to wring out of Jackson'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 20,880 BTU/hr before the moisture allowance.

Other house sizes in Jackson

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 1,600 BTU/hr; a 350 sq ft living room needs about 3,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 6,500 BTU/hr.

Month by month in Jackson

Jul alone uses 65% of the year's cooling energy. The unit runs the equivalent of 13 hours a year at full output.

Jackson against nearby cities

Of 11 Wyoming cities here, Jackson has the lowest cooling load. The range runs from Jackson at 21,700 BTU/hr to Casper at 30,000.

Where Jackson's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Moose 1 Nne, 13.5 miles from the center of Jackson at 6,466 ft above sea level. That is close enough that the station's summers are Jackson's summers.

No other city in this set uses Moose 1 Nne, so this sizing is Jackson's alone.

The sun over Jackson in late July

At 43.47°N, the noon sun on 21 July stands 66.9° above the horizon over Jackson and the day runs 14 h 45 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. Long days mean the house keeps gaining heat into the evening, well after the outdoor peak.

10,680 people live in Jackson, the 10th largest of the 11 Wyoming cities sized on this site. Coordinates used: 43.4719, -110.7753.

Jackson AC sizing questions