What size AC for Boone, NC? 2 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Boone 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 Boone 1 Se (1.1 mi away). Jul is the hottest month, averaging a high of 79°F and a low of 57.7°F, with about 0 days 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 377 kWh a year at SEER2 14.3, or roughly $56 at North Carolina's average residential rate of 14.94¢ per kWh. Cooling runs 3 months of the year here.

What drives the load in Boone

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 Boone'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 Boone

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 Boone

Jul alone uses 40% of the year's cooling energy. The unit runs the equivalent of 248 hours a year at full output.

Boone against nearby cities

Of 91 North Carolina cities here, Boone has the lowest cooling load. The range runs from Boone at 21,700 BTU/hr to Lumberton at 40,200.

Where Boone's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Boone 1 Se, 1.1 miles from the center of Boone at 3,100 ft above sea level. That is close enough that the station's summers are Boone's summers.

No other city in this set uses Boone 1 Se, so this sizing is Boone's alone.

The sun over Boone in late July

At 36.21°N, the noon sun on 21 July stands 74.2° above the horizon over Boone and the day runs 14 h 06 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.

20,080 people live in Boone, the 51st largest of the 91 North Carolina cities sized on this site. Coordinates used: 36.2138, -81.6652.

Boone AC sizing questions