What size AC for Danville, VA? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 33,100 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 27% 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 3 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 725 square feet in this climate. For a single room, size by the room: 16.6 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Danville Regional Airport (4.1 mi away). Jul is the hottest month, averaging a high of 88.8°F and a low of 67°F, with about 42 days a year at 90°F or more. That gives a design temperature of 94°F against 75°F inside.

What it costs to run

About 1,921 kWh a year at SEER2 14.3, or roughly $326 at Virginia's average residential rate of 16.95¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Danville

Of the 33,100 BTU/hr, 13,680 comes through walls, roof and windows on a 94°F afternoon (41%), 13,000 is sun on the house (39%), 2,120 is four people and their appliances, and 4,300 is moisture the coil has to wring out of Danville'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 28,800 BTU/hr before the moisture allowance.

Other house sizes in Danville

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,500 BTU/hr; a 350 sq ft living room needs about 5,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,000 BTU/hr.

Month by month in Danville

Jul alone uses 29% of the year's cooling energy. The unit runs the equivalent of 829 hours a year at full output.

Danville against nearby cities

Of 39 Virginia cities here, Danville has the 16th highest cooling load. The range runs from Christiansburg at 24,900 BTU/hr to Chesapeake at 42,100.

Where Danville's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Danville Regional Airport, 4.1 miles from the center of Danville at 552 ft above sea level. That is close enough that the station's summers are Danville's summers.

No other city in this set uses Danville Regional Airport, so this sizing is Danville's alone.

The sun over Danville in late July

At 36.58°N, the noon sun on 21 July stands 73.8° above the horizon over Danville and the day runs 14 h 08 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.

41,993 people live in Danville, the 17th largest of the 39 Virginia cities sized on this site. Coordinates used: 36.5833, -79.4081.

Danville AC sizing questions