What size AC for West Chester, PA? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 26,400 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 59% 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 908 square feet in this climate. For a single room, size by the room: 13.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Avondale 2 N (11.8 mi away). Jul is the hottest month, averaging a high of 83.6°F and a low of 63.7°F, with about 8 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 1,015 kWh a year at SEER2 14.3, or roughly $214 at Pennsylvania's average residential rate of 21.13¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in West Chester

Of the 26,400 BTU/hr, 9,360 comes through walls, roof and windows on a 88°F afternoon (35%), 13,000 is sun on the house (49%), 2,120 is four people and their appliances, and 2,000 is moisture the coil has to wring out of West Chester's summer air (8%).

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 West Chester

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 4,600 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,900 BTU/hr.

Month by month in West Chester

Jul alone uses 35% of the year's cooling energy. The unit runs the equivalent of 549 hours a year at full output.

West Chester against nearby cities

Of 68 Pennsylvania cities here, West Chester has the 52nd highest cooling load. The range runs from St. Marys at 21,700 BTU/hr to Philadelphia at 34,300.

Where West Chester's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Avondale 2 N, 11.8 miles from the center of West Chester at 400 ft above sea level. That is close enough that the station's summers are West Chester's summers.

1 other city uses the same station and get the same climate inputs. The closest to West Chester: Coatesville (11 mi away, 8.9 mi from the station). West Chester is farther from the station than 1 of them.

The sun over West Chester in late July

At 39.96°N, the noon sun on 21 July stands 70.4° above the horizon over West Chester and the day runs 14 h 25 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.

22,758 people live in West Chester, the 25th largest of the 68 Pennsylvania cities sized on this site. Coordinates used: 39.9599, -75.6054.

West Chester AC sizing questions