What size AC for Morgantown, WV? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 27,200 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 54% 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 2.5 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 882 square feet in this climate. For a single room, size by the room: 13.6 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Morgantown Municipal Airport (1.6 mi away). Jul is the hottest month, averaging a high of 84.4°F and a low of 63.8°F, with about 13 days a year at 90°F or more. That gives a design temperature of 89°F against 75°F inside.

What it costs to run

About 1,214 kWh a year at SEER2 14.3, or roughly $189 at West Virginia's average residential rate of 15.58¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Morgantown

Of the 27,200 BTU/hr, 10,080 comes through walls, roof and windows on a 89°F afternoon (37%), 13,000 is sun on the house (48%), 2,120 is four people and their appliances, and 2,000 is moisture the coil has to wring out of Morgantown's summer air (7%).

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 25,200 BTU/hr before the moisture allowance.

Other house sizes in Morgantown

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,000 BTU/hr; a 350 sq ft living room needs about 4,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,200 BTU/hr.

Month by month in Morgantown

Jul alone uses 30% of the year's cooling energy. The unit runs the equivalent of 638 hours a year at full output.

Morgantown against nearby cities

Of 13 West Virginia cities here, Morgantown has the 10th highest cooling load. The range runs from Beckley at 24,100 BTU/hr to Parkersburg at 31,500.

Where Morgantown's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Morgantown Municipal Airport, 1.6 miles from the center of Morgantown at 1,226 ft above sea level. That is close enough that the station's summers are Morgantown's summers.

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

The sun over Morgantown in late July

At 39.64°N, the noon sun on 21 July stands 70.8° above the horizon over Morgantown and the day runs 14 h 24 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.

30,490 people live in Morgantown, the 3rd largest of the 13 West Virginia cities sized on this site. Coordinates used: 39.6375, -79.9469.

Morgantown AC sizing questions